Develop Reference

How to assign an integer value to an imageView in Android Studio?

I am creating a feedback app where a user has to click one of the 5 imageViews (1-5 rating) based on his/her experience. My primary aim is to extract the integer value of this rating from the imageView click and push it to a SQLite database.
I am trying to use setTag() and getTag() but to no avail. Any help would be much appreciated. Thanks in advance.
activity_main.xml -
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="#+id/textViewName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="99dp"
android:layout_marginLeft="99dp"
android:layout_marginTop="64dp"
android:layout_marginEnd="172dp"
android:layout_marginRight="172dp"
android:layout_marginBottom="151dp"
android:text="Name"
android:textSize="22sp"
app:layout_constraintBottom_toTopOf="#+id/imageView1"
app:layout_constraintEnd_toStartOf="#+id/editTextPersonName"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="#+id/editTextPersonName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="172dp"
android:layout_marginLeft="172dp"
android:layout_marginTop="54dp"
android:ems="10"
android:hint="Full Name"
android:inputType="textPersonName"
app:layout_constraintStart_toEndOf="#+id/textViewName"
app:layout_constraintTop_toTopOf="parent" />
<ImageView
android:id="#+id/imageView1"
android:layout_width="92dp"
android:layout_height="103dp"
android:layout_marginStart="35dp"
android:layout_marginLeft="35dp"
android:layout_marginTop="151dp"
android:layout_marginEnd="47dp"
android:layout_marginRight="47dp"
android:tag="1"
app:layout_constraintEnd_toStartOf="#+id/imageView2"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textViewName"
tools:srcCompat="#tools:sample/avatars" />
<ImageView
android:id="#+id/imageView4"
android:layout_width="92dp"
android:layout_height="103dp"
android:layout_marginStart="60dp"
android:layout_marginLeft="60dp"
android:layout_marginBottom="64dp"
android:tag="4"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toEndOf="#+id/imageView3"
tools:srcCompat="#tools:sample/avatars" />
<ImageView
android:id="#+id/imageView5"
android:layout_width="92dp"
android:layout_height="103dp"
android:layout_marginStart="46dp"
android:layout_marginLeft="46dp"
android:layout_marginEnd="40dp"
android:layout_marginRight="40dp"
android:layout_marginBottom="64dp"
android:tag="5"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.833"
app:layout_constraintStart_toEndOf="#+id/imageView4"
tools:srcCompat="#tools:sample/avatars" />
<ImageView
android:id="#+id/imageView2"
android:layout_width="92dp"
android:layout_height="103dp"
android:layout_marginStart="48dp"
android:layout_marginLeft="48dp"
android:layout_marginBottom="63dp"
android:tag="2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toEndOf="#+id/imageView1"
tools:srcCompat="#tools:sample/avatars" />
<ImageView
android:id="#+id/imageView3"
android:layout_width="92dp"
android:layout_height="103dp"
android:layout_marginStart="53dp"
android:layout_marginLeft="53dp"
android:layout_marginTop="80dp"
android:layout_marginEnd="49dp"
android:layout_marginRight="49dp"
android:tag="3"
app:layout_constraintEnd_toStartOf="#+id/imageView4"
app:layout_constraintStart_toEndOf="#+id/imageView2"
app:layout_constraintTop_toBottomOf="#+id/textView"
tools:srcCompat="#tools:sample/avatars" />
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="333dp"
android:layout_marginLeft="333dp"
android:layout_marginTop="41dp"
android:layout_marginEnd="340dp"
android:layout_marginRight="340dp"
android:layout_marginBottom="75dp"
android:text="Were you satisfied with our hygiene standards?"
android:textSize="18sp"
app:layout_constraintBottom_toTopOf="#+id/imageView3"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/editTextPersonName" />
</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity.java -
public class MainActivity extends AppCompatActivity {
EditText name;
ImageView oneStar;
ImageView twoStar;
ImageView threeStar;
ImageView fourStar;
ImageView fiveStar;
Intent intent;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
name = (EditText) findViewById(R.id.editTextPersonName);
oneStar = (ImageView) findViewById(R.id.imageView1);
oneStar.setTag(1);
oneStar.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
String username = name.getText().toString()+"\n";
Toast.makeText(MainActivity.this, (Integer) oneStar.getTag(), Toast.LENGTH_SHORT).show();
}
});
}
}

Try to replace oneStar.getTag() with view.getTag()

If you want to get the tag, and display it as a Toast message, the instead of casting it into an Integer object convert it to String using .toString method.

Second parameter of Toast.makeText is interger, but you can't pass any integer. It must be the resource Id of a string (R.string.your_string). Remove "(Integer)" and it should solve your problem.
I don't know exactly what are your requirements and in case you missed it, there is a build in rating barin Android. You can check the tutorial here

it is less code and less error prone if you just add this to ImageView: android:onClick="imageViewClick", and create a handler in MainActivity like this:
public void imageViewClick(View view) {
String username = name.getText().toString()+"\n";
Toast.makeText(MainActivity.this, (Integer)view.getTag(),Toast.LENGTH_SHORT).show();
}

How to set a textView to visible after an onClick event and Activity change?

I have three passages in my scrollview that need to each become visible after an onclick event on one of three buttons.
I have currently set them to all invisible. And since I cannot get it to work, I am only trying it out with one of the passages.
Because of this I created a private textview constant for only the first passage. But after I pass the intent to switch the activity, I also try to turn the view on that package to visible.
I have included my MainActivity.java and the xml file I used to set invisible.
package com.example.threebuttons;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private TextView passage1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
passage1 = findViewById(R.id.passage_1);
}
public void launchPassageOne(View view) {
passage1.setVisibility(view.VISIBLE);
Intent intent = new Intent(this, PassageActivity.class);
startActivity(intent) ;
}
public void launchPassageTwo(View view) {
Intent intent = new Intent(this, PassageActivity.class);
startActivity(intent) ;
}
public void launchPassageThree(View view) {
Intent intent = new Intent(this, PassageActivity.class);
startActivity(intent) ;
}
}
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".PassageActivity">
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<EditText
android:id="#+id/passage_1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:gravity="start|top"
android:inputType="textMultiLine"
android:text="#string/passage1"
android:visibility="invisible"/>
<EditText
android:id="#+id/passage_2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:gravity="start|top"
android:inputType="textMultiLine"
android:text="#string/passage2"
android:visibility="invisible"/>
<EditText
android:id="#+id/passage_3"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:gravity="start|top"
android:inputType="textMultiLine"
android:text="#string/passage3"
android:visibility="invisible"/>
</LinearLayout>
</ScrollView>
</androidx.constraintlayout.widget.ConstraintLayout>
My program just crashes. And I cannot find any error messages.
How can I make the packages visible whenever I want the activity to change?
There are three passages that I want to each become visible for the respective button, then turn invisible if the back button is pressed.

It seams the three views are in the started activity. And so you can't change their visibility because they haven't been created.
Add this before you start the activity
intent.putExtra("passageNum", 1)
Then call startActivity(intent)
In PassageAactivity onCreate do the following :
If (getIntent().hasExtra("passageNum") && getIntent().getExtras().getInt("passageNum") == 1)
passage1.setVisibility(View.VISIBLE)
And so on for the other views

passage1.setVisibility(View.VISIBLE)
read more about views and how to modify their behavior here :
https://developer.android.com/reference/android/view/View

Use View.VISIBLE, capital V, it's a integer constant from the View class. Remove the View argument from the method launchPassageOne:
public void launchPassageOne() {
passage1.setVisibility(View.VISIBLE);
Intent intent = new Intent(this, PassageActivity.class);
startActivity(intent) ;
}

Image click hereWhatever I understood with your code I got that you are not initializing your methods in On create, whatever defined outside the On create will not be used until or unless called from inside On create method.
Designed some code may help you understanding in a better way.
In below code, I made text views scrollable, but you can only scroll if text is too long to fill the entire textview.
MainActivity.java
package com.example.threebuttons;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.text.method.ScrollingMovementMethod;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
EditText edit1;
EditText edit2;
EditText edit3;
Button btn1;
Button btn2;
Button btn3;
Button btnV;
Button btnI;
TextView t1;
TextView t2;
TextView t3;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// defining id for edit texts
edit1=findViewById(R.id.passage_1);
edit2=findViewById(R.id.passage_2);
edit3=findViewById(R.id.passage_3);
// defining id for buttons
btn1=findViewById(R.id.button_1);
btn2=findViewById(R.id.button_2);
btn3=findViewById(R.id.button_3);
btnV=findViewById(R.id.btnvisi);
btnI=findViewById(R.id.btninvisi);
// defining id for text views
t1=findViewById(R.id.textview1);
t2=findViewById(R.id.textview2);
t3=findViewById(R.id.textview3);
// making text views scrollable
t1.setMovementMethod(new ScrollingMovementMethod());
t2.setMovementMethod(new ScrollingMovementMethod());
t3.setMovementMethod(new ScrollingMovementMethod());
btn1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
t1.setText(edit1.getText().toString());
}
});
btn2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
t2.setText(edit2.getText().toString());
}
});
btn3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
t3.setText(edit3.getText().toString());
}
});
btnV.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//Making passages Visible
t1.setVisibility(View.VISIBLE);
t2.setVisibility(View.VISIBLE);
t3.setVisibility(View.VISIBLE);
}
});
btnI.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
t1.setVisibility(View.INVISIBLE);
t2.setVisibility(View.INVISIBLE);
t3.setVisibility(View.INVISIBLE);
}
});
}
}
Set activitymain.xml as below
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#2196F3"
tools:context=".MainActivity">
<EditText
android:id="#+id/passage_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:ems="10"
android:hint="passage 1"
android:inputType="textPersonName"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.043"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.016" />
<EditText
android:id="#+id/passage_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:ems="10"
android:hint="Passage 2"
android:inputType="textPersonName"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.043"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.102" />
<EditText
android:id="#+id/passage_3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:ems="10"
android:hint="Passage 3"
android:inputType="textPersonName"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.043"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.194" />
<Button
android:id="#+id/button_1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:text="Button"
app:layout_constraintBottom_toTopOf="#+id/passage_2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/passage_1"
app:layout_constraintTop_toTopOf="#+id/passage_1" />
<Button
android:id="#+id/button_2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:text="Button"
app:layout_constraintBottom_toTopOf="#+id/passage_3"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/passage_2"
app:layout_constraintTop_toTopOf="#+id/passage_2" />
<Button
android:id="#+id/button_3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:text="Button"
app:layout_constraintBottom_toBottomOf="#+id/passage_3"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="#+id/passage_3"
app:layout_constraintTop_toTopOf="#+id/passage_3" />
<TextView
android:id="#+id/textview1"
android:layout_width="319dp"
android:layout_height="74dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:background="#3F51B5"
android:hint="Passage 1"
android:scrollbars="vertical"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.486"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.446"
tools:visibility="invisible" />
<TextView
android:id="#+id/textview2"
android:layout_width="319dp"
android:layout_height="74dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:background="#3F51B5"
android:hint="Passage 2"
android:scrollbars="vertical"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.672"
tools:visibility="invisible" />
<TextView
android:id="#+id/textview3"
android:layout_width="319dp"
android:layout_height="74dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:background="#3F51B5"
android:hint="Passage 3"
android:scrollbars="vertical"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.486"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.895"
tools:visibility="invisible" />
<Button
android:id="#+id/btnvisi"
android:layout_width="175dp"
android:layout_height="44dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:text="Passage Visible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.036"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.299" />
<Button
android:id="#+id/btninvisi"
android:layout_width="174dp"
android:layout_height="47dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
android:text="passage invisible"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.886"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.3" />
</androidx.constraintlayout.widget.ConstraintLayout>
I hope it makes you understand in a better way,
Thanks

Button not responding when clicked

I am new to Android Programming and I wanted to make a simple app where the user would enter there name and after they click the button, it would say Hello (name of person). Also the button will change to thanks for clicking me after it is clicked. I have looked through the code but I am having a hard time finding the error. I have the code down below. I will also add the xml under the code.
code
public class MainActivity extends AppCompatActivity {
private EditText yourName;
private TextView outputName;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
yourName = (EditText)findViewById(R.id.inputText);
outputName = (TextView)findViewById(R.id.outputText);
}
public void printHello (View view){
Button button =(Button) view;
((Button)view).setText("Thanks for Clicking Me!");
yourName =(EditText)findViewById(R.id.inputText);
outputName =(TextView)findViewById(R.id.outputText);
outputName.setText("Hello, "+ yourName.getText());
outputName.setVisibility(View.VISIBLE);
}
}
Here is the xml also
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="328dp"
android:text="Talk to Me"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.078" />
<TextView
android:id="#+id/Label1"
android:layout_width="0dp"
android:layout_height="31dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="32dp"
android:text=" Please Enter Your Name"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
<TextView
android:id="#+id/outputText"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="88dp"
android:text="TextView"
android:visibility="invisible"
app:layout_constraintBottom_toTopOf="#+id/button"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/inputText"
app:layout_constraintVertical_bias="0.0" />
<EditText
android:id="#+id/inputText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="72dp"
android:ems="10"
android:inputType="textPersonName"
android:text="Name"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.503"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/Label1" />
</android.support.constraint.ConstraintLayout>

You need to have an android:onClick="printHello" inside of the button XML to link the button to the function inside of the Java class. Then any time the button is clicked, it calls printHello and does what you need to.

IllegalStateException: Could not execute method for android:onClick when trying to migrate to another page?

I've been working on an app (which i took over from another student's final year project on my lecturer's recommendation) due to university internship requirements and am having issues with migrating from the main menu screen to the login screen.
(Only the login page has issues, going from the application's main menu to the register page has no issues whatsoever, hence i assume the problem might be either in the xml files or the LoginActivity.java, but have no idea how.)
logcat errors are listed as such:
TAL EXCEPTION: main
Process: com.finchvpn.androidcloudpark, PID: 1579
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:389)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:384)
at android.view.View.performClick(View.java:4438) 
at android.view.View$PerformClick.run(View.java:18422) 
at android.os.Handler.handleCallback(Handler.java:733) 
at android.os.Handler.dispatchMessage(Handler.java:95) 
at android.os.Looper.loop(Looper.java:136) 
at android.app.ActivityThread.main(ActivityThread.java:5001) 
at java.lang.reflect.Method.invokeNative(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:515) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601) 
at dalvik.system.NativeStart.main(Native Method) 
Caused by: java.lang.NullPointerException
at com.finchvpn.androidcloudpark.MainActivity.loginButtonClick(MainActivity.java:74)
Below are related xml files:
Main menu xml file:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/asd2">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar3"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#drawable/side_nav_bar"
app:popupTheme="#style/PopupOverlay" />
<TextView
android:id="#+id/toolbar_title"
android:layout_width="239dp"
android:layout_height="73dp"
android:layout_gravity="center"
android:layout_marginBottom="8dp"
android:text="CloudPark.my"
android:textColor="#color/md_white_1000"
android:textSize="14pt"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.11"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.014" />
<ImageButton
android:id="#+id/loginButtonPic"
android:layout_width="132dp"
android:layout_height="120dp"
android:layout_gravity="end"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_weight="1"
android:background="#null"
android:onClick="loginButtonClick"
android:scaleType="fitCenter"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.19"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.559"
app:srcCompat="#drawable/loginnew2"
tools:ignore="ContentDescription" />
<ImageButton
android:id="#+id/RegisterButtonPic"
android:layout_width="132dp"
android:layout_height="120dp"
android:layout_gravity="end"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:layout_weight="1"
android:background="#null"
android:onClick="registerButtonClick"
android:scaleType="fitCenter"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.813"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.559"
app:srcCompat="#drawable/registernew1"
tools:ignore="ContentDescription" />
<TextView
android:id="#+id/textView2"
android:layout_width="279dp"
android:layout_height="63dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="CloudPark, the next generation parking app."
android:textColor="#color/md_white_1000"
android:textSize="10pt"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.505"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.181" />
</android.support.constraint.ConstraintLayout>
Login xml file:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#drawable/asd2">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar3"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="#drawable/side_nav_bar"
app:popupTheme="#style/PopupOverlay" />
<TextView
android:id="#+id/toolbar_title"
android:layout_width="307dp"
android:layout_height="91dp"
android:layout_gravity="center"
android:layout_marginBottom="8dp"
android:layout_marginTop="8dp"
android:text="Login"
android:textColor="#color/md_white_1000"
android:textSize="14pt"
android:textStyle="bold"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.506"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0" />
<TextView
android:id="#+id/textView2"
android:layout_width="281dp"
android:layout_height="50dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Enter your credentials to access CloudPark."
android:textColor="#color/md_white_1000"
android:textSize="10pt"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.505"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.181" />
<EditText
android:id="#+id/textUsername"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginTop="8dp"
android:ems="10"
android:hint="Username"
android:inputType="textEmailAddress"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.503"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.352" />
<EditText
android:id="#+id/textPassword"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:ems="10"
android:hint="Password"
android:inputType="textPassword"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.503"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.443" />
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginTop="8dp"
android:background="#0026FF"
android:onClick="loginButtonClick"
android:text="Login to CloudPark"
android:textColor="#FFFF"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.687" />
<android.support.constraint.Guideline
android:id="#+id/guideline"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
app:layout_constraintGuide_begin="20dp" />
</android.support.constraint.ConstraintLayout>
LoginActivity.java
public class LoginActivity extends AppCompatActivity {
private EditText textUsername;
private EditText txtPassword;
private static RestClient restClient = new RestClient();
private SharedPreferences.Editor sharedPreferencesEditor;
#SuppressLint("CommitPrefEdits")
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
try {
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
Objects.requireNonNull(getSupportActionBar()).setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowHomeEnabled(true);
} catch (Exception e) {
}
textUsername = findViewById(R.id.textUsername);
txtPassword = findViewById(R.id.textPassword);
SharedPreferences sharedPreferences = getSharedPreferences("UserInfo", 0);
sharedPreferencesEditor = sharedPreferences.edit();
textUsername.setText(sharedPreferences.getString("textUsername", ""));
txtPassword.setText(sharedPreferences.getString("txtPassword", ""));
}
public static RestClient getRestClient() {
return restClient;
}
public void loginButtonClick(View v) {
if (!textUsername.getText().toString().equals("") && !txtPassword.getText().toString().equals("")) {
apiPostLogin(Constants.ANDROID_KEY + ":" + textUsername.getText().toString() + ":" + txtPassword.getText().toString());
sharedPreferencesEditor.putString("textUsername", textUsername.getText().toString());
sharedPreferencesEditor.putString("txtPassword", txtPassword.getText().toString());
sharedPreferencesEditor.commit();
} else {
Toast.makeText(LoginActivity.this, "NULL", Toast.LENGTH_LONG).show();
}
}
private void apiPostLogin(String data) {
final ProgressDialog progress = new ProgressDialog(this);
progress.setTitle("Logging in");
progress.setMessage("Please wait ...");
progress.setCancelable(false); // disable dismiss by tapping outside of the dialog
progress.show();
Call<ResponseBody> call = getRestClient().getLoginService().postLogin(data);
call.enqueue(new Callback<ResponseBody>() {
#Override
public void onResponse(Call<ResponseBody> call, Response<ResponseBody> response) {
if (response.isSuccessful() && response.body() != null) {
try {
String data = response.body().string();
JSONObject jsonObject = new JSONObject(data);
Constants.uid = Integer.parseInt(jsonObject.getString("id"));
Constants.username = jsonObject.getString("username");
Constants.email = jsonObject.getString("email");
Constants.credit = jsonObject.getString("credit");
Constants.qr_code = jsonObject.getString("qr_code");
Constants.created_at = jsonObject.getString("created_at");
Constants.updated_at = jsonObject.getString("updated_at");
Toast.makeText(LoginActivity.this, "apiPostLogin onResponse <<<< \r\n\r\n" + jsonObject.toString(), Toast.LENGTH_LONG).show();
Intent returnIntent = new Intent();
setResult(Activity.RESULT_CANCELED, returnIntent);
finish();
} catch (IOException | JSONException e) {
e.printStackTrace();
}
}
progress.dismiss();
}
#Override
public void onFailure(Call<ResponseBody> call, Throwable t) {
Toast.makeText(LoginActivity.this, "Incorrect username/password, please try again." + t.getMessage(), Toast.LENGTH_LONG).show();
progress.dismiss();
}
});
}
}

I suspect the problem is related with the clash of android:onClick="loginButtonClick" in main menu xml and login xml.
You should not depend on android:onClick attribute for handling View click. It is because when using android:onClick you can't be sure that your method handling the onClick will work. There is no exact mechanism to ensure your code is connected to the View. Another problem is, android:onClick won't work for Fragment. So, I consider using android:onClick as bad practice.
To solve the problem, use setOnClickListener on your View. Coupled with findViewById, your code will more robust because you will always see an error if you are giving an incorrect id for findViewById. To make your code more robust and avoid clashing the id, you need to use a decscriptive name id for the view. Use naming convention like this:
layout name + _ + What the view for + _ + type of view
For example, for your login xml you can use something like this:
....
<Button
android:id="#+id/login_cloudpark_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginTop="8dp"
android:background="#0026FF"
android:text="Login to CloudPark"
android:textColor="#FFFF"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.687" />
<android.support.constraint.Guideline
android:id="#+id/login_begin_gdl"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
app:layout_constraintGuide_begin="20dp" />
...
then use it with findViewById:
public class LoginActivity extends AppCompatActivity {
...
private Button mBtnLogin;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
...
mBtnLogin = findViewById(R.id.login_cloudpark_btn);
}
}
after that, add clickListener to mBtnLogin:
mbtnLogin.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// place your clicking handle code here.
}
});
By doing the above, you will separate the View in xml and your logic cleanly.

Resources$NotFoundException: String resource ID [duplicate]

This question already has answers here:
android.content.res.Resources$NotFoundException: String resource ID #0x0
(8 answers)
Closed 5 years ago.
I try to show in MainActivity from another class by getter a value.
1st I make object and insert to him value from editText.
App crash with android.content.res.Resources$NotFoundException: String resource ID #0x28 What is wrong here ?
Check code:
public class MainActivity extends AppCompatActivity {
EditText editText, editText2;
Button button, button2;
TextView tV;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = findViewById(R.id.button);
button2 = findViewById(R.id.button2);
editText = findViewById(R.id.editText);
editText2 = findViewById(R.id.editText2);
tV = findViewById(R.id.textView);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
int a = Integer.valueOf(editText.getText().toString());
Calculations calc = new Calculations(a){
};
tV.setText(calc.getResult());
}
});
}
2nd Class
public class Calculations {
public int getResult() {
return result;
}
public int result;
public Calculations(int a){
result = a * 10;
}
public Calculations(int a, int b){
result = a * b;
}
}
Here is my layout, maybe this will help
Here is my layout, maybe this will help
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="ge.ger.training.MainActivity">
<EditText
android:id="#+id/editText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:ems="10"
android:inputType="textPersonName"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.222"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.22" />
<EditText
android:id="#+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:ems="10"
android:inputType="textPersonName"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.222"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.351" />
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Transfer value 1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.121"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.498" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Transfer value 1 and 2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.12"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.668" />
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:text="Result"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.109"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.838" />
</android.support.constraint.ConstraintLayout>

Replace your line with below in onClickListener
Calculations calc=new Calculations(a);
tV.setText(String.valueOf(calc.getResult()));