Android Button findViewByID returns null

Android Button findViewByID returns null - java

I had three button on my main form. I added a third. When I try to assign the button using findViewById a null is returned.
This is my main.xml
<?xml version="1.0" encoding="utf-8"?>
<TableLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent" android:weightSum="1" android:clickable="false">
<TextView android:layout_width="wrap_content"
style="#style/TitleText"
android:text="#string/app_name"
android:background="#drawable/black_gradient">
</TextView>
<Button android:id="#+id/btnvalidatemark"
android:background="#drawable/grad_btn_green"
style="#style/ButtonText" android:text="#string/validate_mark_button">
</Button>
<Button android:id="#+id/btncheckregistry"
android:background="#drawable/grad_btn_yellow"
style="#style/ButtonText" android:text="#string/check_registry_button">
</Button>
<Button android:id="#+id/btnregcreds"
android:background="#drawable/grad_btn_red"
style="#style/ButtonText" android:text="#string/registry_config_button">
</Button>
</TableLayout>
This is my Activity code:
package uid.android.uidchecker;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.util.Log;
public class UIDCheckerActivity
extends Activity
{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
Button validatebutton = (Button) findViewById(R.id.btnvalidatemark);
Button checkbutton = (Button) findViewById(R.id.btncheckregistry);
Button setcredbutton = (Button) findViewById(R.id.btnregcreds);
validatebutton.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Intent i = new Intent(UIDCheckerActivity.this, SelectFileActivity.class);
i.putExtra("func", "validatemark");
startActivity(i);
}
});
checkbutton.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
//Intent i = new Intent(UIDCheckerActivity.this, validatemark.class);
Intent i = new Intent(UIDCheckerActivity.this, SelectFileActivity.class);
i.putExtra("func", "checkregisrty");
startActivity(i);
}
});
setcredbutton.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Intent i = new Intent(UIDCheckerActivity.this, RegistryCredsActivity.class);
startActivity(i);
}
});
}
}

Related

How to get Hint and Text of a button In android studio

I am using this code to get the id of the button which is clicked and then use the id to get the text and hint of the same button
I don't know why but maybe this code this crashing the app after I use getID() method.
I am using Relative Layout.
The Java code
package com.example.firstapp;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import androidx.constraintlayout.widget.ConstraintLayout;
import android.annotation.SuppressLint;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity{
public AlertDialog.Builder dialogBuilder;
public AlertDialog dialog;
public EditText Name,Password;
public Button Save,Cancel,temp,ok,x;
public String file_location = "Passwords.txt";
public String name_x,pass_y;
public LinearLayout mylayout = null;
public RelativeLayout rl = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void View_Password(Button x){
ok = (Button) findViewById(R.id.button6);
ok.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
dialog.dismiss();
}
});
};
public void NewPassword(){
dialogBuilder = new AlertDialog.Builder(this);
final View NewPassSaveView = getLayoutInflater().inflate(R.layout.newpasspopup, null);
Name = (EditText) NewPassSaveView.findViewById(R.id.editTextTextPersonName);
Password = (EditText) NewPassSaveView.findViewById(R.id.editTextTextPersonName2);
Save = (Button) NewPassSaveView.findViewById(R.id.button4);
Cancel = (Button) NewPassSaveView.findViewById(R.id.button);
dialogBuilder.setView(NewPassSaveView);
dialog = dialogBuilder.create();
dialog.show();
Save.setOnClickListener(new View.OnClickListener() {
#SuppressLint("ResourceType")
#Override
public void onClick(View view) {
if (TextUtils.isEmpty(Name.getText().toString())) {
Name.setError("This Field is compulsory");
return;
} else if (TextUtils.isEmpty(Password.getText().toString())) {
Password.setError("This Field is compulsory");
return;
}
rl = (RelativeLayout) findViewById(R.id.layout2);
Toast.makeText(getApplicationContext(), "Password Saving...", Toast.LENGTH_SHORT).show();
Toast.makeText(getApplicationContext(), "Password Saved", Toast.LENGTH_SHORT).show();
Button temp = new Button(MainActivity.this);
temp.setLayoutParams(new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.MATCH_PARENT,
RelativeLayout.LayoutParams.WRAP_CONTENT
));
rl.addView(temp);
temp.setText(Name.getText().toString());
temp.setHint(Password.getText().toString());
temp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
int btn_id = v.getId();
btn2string(btn_id);
}
});
dialog.dismiss();
}
});
Cancel.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
dialog.dismiss();
}
});
}
public void AddNew(View view) {
NewPassword();
}
public void btn2string(int x){
Button btn = findViewById(x);
name_x = btn.getText().toString();
pass_y = btn.getHint().toString();
See_Password(name_x,pass_y);
}
public void See_Password(String name,String pass){
Toast.makeText(getApplicationContext(), "Name: "+name+"\n"+"Password: "+pass, Toast.LENGTH_SHORT).show();
}
}
//The 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:id="#+id/heading"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<TextView
android:id="#+id/textView4"
android:layout_width="319dp"
android:layout_height="50dp"
android:text="Password Manager"
android:textSize="34sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.051" />
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="28dp"
android:layout_marginRight="28dp"
android:onClick="AddNew"
android:text="Add new"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView4"
app:layout_constraintVertical_bias="0.973" />
<RelativeLayout
android:id="#+id/layout2"
android:layout_width="366dp"
android:layout_height="541dp"
android:layout_marginTop="28dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.488"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView4"
app:layout_constraintVertical_bias="0.0"/>
</androidx.constraintlayout.widget.ConstraintLayout>
Please tell if there is any other way to do this or tell the mistakes in the above code so that I can get the hint and text of that button which is clicked...
Thank You.

Inside,
NewPassword()
method just change the following code.
public void NewPassword(){
......
save.setOnClickListener(...){
........
temp.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v){
int btn_id = v.getId(); // remove this line.
btn2String(temp); //directly pass temp i.e. Button you created.
}
});
dialog.dismiss();
}
});
..........
}
And, pass Button type as a parameter in btn2String() method. as below:
public void btn2String(Button x){
Button btn = findViewById(x); // remove this line of code.
name_x = x.getText().toString();
pass_y = x.getHint().toString();
See_Password(name_x, pass_y);
}

Passing data between activities for a voting app

I am new to android programming and have ran into a problem. I am trying to create a voting app where when a user opens up the application and the MainActivity is shown, from here they press a button to go into the second Screen (Screen2) which shows images of people and their names as buttons. When a persons name (in a button on Screen2) is pressed , a text field shows the number of times the button is pressed in an another activity (Screen4) . The problem here is that when i try to show this (Screen4), the app crashes. I am quite new to this so if you didn't understand my issue or need more information please let me know. Any help is appreciated. Thank you.
EDIT : After some help I used Intent to try send the data across but now when when the button in screen2 is pressed the app refreshes and then takes me back to the mainActivity and when this process is tried again the app crashes.
This is the new Screen2 :
package com.example.myapplication1;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class Screen2 extends AppCompatActivity {
TextView showValue;
int counter = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_screen2);
showValue = findViewById(R.id.VoteCountAnnie);//VoteCountAnnie is the On click for the Textview in a different activity.
}
public void AnCount(View v) {
//increase the count
counter++;
showValue.setText(Integer.toString(counter));
}
public void ButtonToGoToTheOtherActivity(View v) {
Intent intent = new Intent(this, Screen4.class);
intent.putExtra("valueOfCounter", counter); //the code for sending data to the other activity.
startActivity(intent);
}
}
This is the XML for screen 2 :
<?xml version="1.0" encoding="utf-8"?>
<ScrollView 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">
<androidx.constraintlayout.widget.ConstraintLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
tools:context=".Screen2">
<Button
android:id="#+id/AnnieBtn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="32dp"
android:layout_marginLeft="32dp"
android:text="#string/annie_liou"
android:onClick="AnCount"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/imageView5"
/>
This is my Screen4:
package com.example.myapplication1;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class Screen4 extends AppCompatActivity {
private Button Button3;
int counter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_screen4);
Button3 = (Button) findViewById(R.id.Button3);
Button3.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) { openActivity4();
}
}
);
counter = getIntent().getIntExtra("valueOfCounter", 0); // 0 is default value
}
public void openActivity4() {
Intent intent = new Intent(Screen4.this, MainActivity.class);
startActivity(intent);
}
}
Here is the XML for screen4:
<?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:id="#+id/MainScreen"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".Screen4">
<TextView
android:id="#+id/textView5"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="193dp"
android:layout_marginLeft="193dp"
android:layout_marginEnd="109dp"
android:layout_marginRight="109dp"
android:layout_marginBottom="660dp"
android:text="This is 4th screen"
android:textSize="32sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.664"
app:layout_constraintStart_toStartOf="parent" />
<Button
android:id="#+id/Button3" // return to main screen
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="532dp"
android:text="Return"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView5" />
<TextView
android:id="#+id/VoteCountAnnie" // textview where i want the increment to show
android:layout_width="121dp"
android:gravity="center"
android:layout_height="52dp"
android:layout_marginStart="116dp"
android:layout_marginLeft="116dp"
android:layout_marginTop="82dp"
android:layout_marginEnd="174dp"
android:layout_marginRight="174dp"
android:text="0"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="#+id/textView5" />
</androidx.constraintlayout.widget.ConstraintLayout>
This is my main Activity Screen (not used for the clicking but if there is something wrong in this that could affect the other Screens please let me know) :
package com.example.myapplication1;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
private Button button;
private Button button2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
openActivity2();
}
});
button2 = (Button) findViewById(R.id.button2);
button2.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
openActivity3();
}
}
);
}
public void openActivity2() {
Intent intent = new Intent(this, Screen2.class);
startActivity(intent);
}
public void openActivity3() {
Intent intent = new Intent(this, Screen3.class);
startActivity(intent);
}
}
Here is the XML for screen 4:

This works same using intent .
Main Class :
package com.example.cameraone;
import android.content.Intent;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
public static String EXTRA_VOTE_KEY = "com.example.cameraone.EXTRA_VOTE_KEY";
private Button counter,show;
private int count = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if(savedInstanceState != null){
count = savedInstanceState.getInt(EXTRA_VOTE_KEY);
}
counter = findViewById(R.id.bt_counter);
show = findViewById(R.id.bt_show);
counter.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
count++;
}
});
show.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
go();
}
});
/* Intent intent = new Intent(this,DisplayCount.class);
//intent.putExtras(intent);
startActivity(intent,bundle);*/
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(EXTRA_VOTE_KEY,count);
}
public void go(){
Intent intent = new Intent(this,DisplayCount.class);
intent.putExtra(EXTRA_VOTE_KEY,count);
startActivity(intent);
}
}
Activity of Main Class :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
tools:context=".MainActivity">
<Button
android:id="#+id/bt_counter"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:text="PressMe"
/>
<Button
android:id="#+id/bt_show"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/bt_counter"
android:text="Done"
/>
</RelativeLayout
Display Class :
package com.example.cameraone;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.widget.Button;
import android.widget.TextView;
import org.w3c.dom.Text;
public class DisplayCount extends AppCompatActivity{
private TextView textView;
private int count;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.display_count_activity);
textView = findViewById(R.id.tv_vote_count);
Intent intent = getIntent();
count = intent.getIntExtra(MainActivity.EXTRA_VOTE_KEY,0);
textView.setText(Integer.toString(count));
}
}
Activity of display class :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="center">
<TextView
android:id="#+id/tv_vote_count"
android:layout_width="wrap_content"
android:inputType="number"
android:layout_height="wrap_content"
android:textStyle="bold"
android:maxLength="10"/>
</RelativeLayout>
Manifest :
include following in your manifest file :
<activity android: name =".DisplayCount"></activity>

add following to manifest :
// Main Activity //
- List item
package com.example.cameraone;
import android.content.Intent;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends AppCompatActivity {
public static String EXTRA_VOTE_KEY = "com.example.cameraone.EXTRA_VOTE_KEY";
private Button counter,show;
private int count = 0;
#Override
protected void onCreate(#Nullable final Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
counter = findViewById(R.id.bt_counter);
show = findViewById(R.id.bt_show);
counter.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
count++;
}
});
show.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
go();
}
});
}
public void go(){
DisplayCount.setVoteCount(count);
Intent intent = new Intent(this, DisplayCount.class);
startActivity(intent);
}
#Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putInt(EXTRA_VOTE_KEY,count);
}
}
/** Class to display: **/
- List item
package com.example.cameraone;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.widget.Button;
import android.widget.TextView;
import org.w3c.dom.Text;
public class DisplayCount extends AppCompatActivity{
private TextView textView ;
private static int count ;
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.display_count_activity);
textView = findViewById(R.id.tv_vote_count);
textView.setText(Integer.toString(count));`enter code here`
}
public static void setVoteCount(int c){
count = c;
}
}
/***** Activity files *****/
- List item
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="center">
<TextView
android:id="#+id/tv_vote_count"
android:layout_width="wrap_content"
android:inputType="number"
android:layout_height="wrap_content"
android:textStyle="bold"
android:maxLength="10"/>
</RelativeLayout>
/**** Activity That display's ****/
-List item
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
tools:context=".MainActivity">
<Button
android:id="#+id/bt_counter"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:text="PressMe"
/>
<Button
android:id="#+id/bt_show"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/bt_counter"
android:text="Done"
/>
</RelativeLayout>

As Mike M. said you are using id of a textview which is in a different activity. In android we cannot access ids of views in a different activity. We can only access ids of view in the same activity in which we are.
So that is for the error you are getting.
For accessing Data from another activity you can pass the data like this:
public class Screen2 extends AppCompatActivity {
int counter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_screen1);
showValue = (TextView) findViewById(R.id.VoteCountAnnie);//VoteCountAnnie is the Id for the Textview in a different activity.
}
public void AnnieCountInc (View view) {
//increase the count
counter++;
showValue.setText(Integer.toString(counter));
}
//make another button with a method like
public void ButtonToGoToTheOtherActivity(View view){
Intent intent =new Intent(this,Screen4.class);
intent.putExtra("valueOfCounter",counter); //the code for sending data to the other activity.
startActivity(intent);
}
Then in your Screen4 activity you can get the value of "counter" in the onCreate method by:
counter = getIntent().getIntExtra("valueOfCounter",0); // 0 is default value
This is one method.
You can also use a static variable to pass on data easily by defining your counter varaible as
public static int counter;
Then you can access it directly and it will show you the value.

How to move a setText() to a new activity on Android Studio?

I am tying to make a basket and want depending on what button is pressed the price that is shown on the screen then appear in the basket (new activity) in TextView09 ( section of the table) but at the moment what is appearing is android.support.v7.widget.App...
Here is the activity page for the product:
package com.example.emily.woodensigns;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.view.LayoutInflater;
public class Letters extends AppCompatActivity {
int txtSize = 14;
EditText Wood;
Button bSize, bSize1, bSize2, bSize3, bBasket;
public int count = 5;
private LayoutInflater mInflater;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_letters);
Wood = (EditText) findViewById(R.id.Wood);
Button bSize = (Button) findViewById(R.id.bSize);
Button bSize1 = (Button) findViewById(R.id.bSize1);
Button bSize2 = (Button) findViewById(R.id.bSize2);
Button bSize3 = (Button) findViewById(R.id.bSize3);
Button bBasket = (Button) findViewById(R.id.bBasket);
final TextView price = (TextView) findViewById(R.id.price);
bSize.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Wood.setTextSize(40);
price.setText("£10");
TextView price = (TextView) findViewById(R.id.price);
String pri = price.getText().toString();
Intent intent2 = new Intent(Letters.this, Letters.class);
intent2.putExtra("£",pri);
}
});
bSize1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Wood.setTextSize(60);
price.setText("£20");
}
});
bSize2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Wood.setTextSize(100);
price.setText("£35");
}
});
bSize3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Wood.setTextSize(150);
price.setText("£50");
}
});
bBasket.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
EditText Wood = (EditText) findViewById(R.id.Wood);
String str = Wood.getText().toString();
if (str.length() == 0) {
Wood.requestFocus();
Wood.setError("FIELD CANNOT BE EMPTY");
} else if (str.length() >= 2) {
Wood.requestFocus();
Wood.setError("You can only type one letter!");
} else {
Intent intent2 = new Intent(Letters.this, Basket.class);
intent2.putExtra("MY_INFO",str + " - Letters" + price );
startActivity(intent2);
}
}
});
}
}
Activity for the Basket:
package com.example.emily.woodensigns;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.EditText;
import android.widget.Toast;
import android.util.Log;
public class Basket extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.content_basket);
TextView TextView08 = (TextView) findViewById(R.id.TextView08);
TextView TextView09 = (TextView) findViewById(R.id.TextView09);
Button bCheckout=(Button) findViewById(R.id.bCheckout);
String strFromActivity = getIntent().getStringExtra("MY_INFO");
TextView08.setText(strFromActivity);
String priFromActivity = getIntent().getStringExtra("£" );
TextView09.setText(priFromActivity);
Toast.makeText(getBaseContext(),priFromActivity, Toast.LENGTH_LONG).show();
bCheckout.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent intent2 = new Intent(Basket.this, customerDetails.class);
startActivity(intent2);
}
});
}
}
Basket xml file:
<TableLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="259dp"
android:shrinkColumns="*" android:stretchColumns="*" android:background="#ffffff">
<!-- Row 1 with single column -->
<TableRow
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:gravity="center_horizontal">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:textSize="18dp"
android:text=""
android:layout_span="3"
android:padding="18dip"
android:background="#b0b0b0"
android:textColor="#000"/>
</TableRow>
<!-- Row 2 with 3 columns -->
<TableRow
android:id="#+id/tableRow1"
android:layout_height="wrap_content"
android:layout_width="match_parent">
<TextView
android:id="#+id/TextView04"
android:layout_weight="1"
android:background="#dcdcdc"
android:textColor="#000000"
android:padding="20dip"
android:gravity="left"/>
<TextView
android:id="#+id/TextView05"
android:text="Product"
android:layout_weight="1"
android:background="#dcdcdc"
android:textColor="#000000"
android:padding="20dip"
android:gravity="center"/>
<TextView
android:id="#+id/TextView06"
android:text="Price"
android:layout_weight="1"
android:background="#d3d3d3"
android:textColor="#000000"
android:padding="20dip"
android:gravity="center"/>
</TableRow>
<TableRow>
<TextView
android:id="#+id/TextView07"
android:layout_weight="1"
android:background="#dcdcdc"
android:textColor="#000000"
android:padding="20dip"
android:gravity="left"/>
<TextView
android:id="#+id/TextView08"
android:text="Product"
android:layout_weight="1"
android:background="#dcdcdc"
android:textColor="#000000"
android:padding="20dip"
android:gravity="center"/>
<TextView
android:id="#+id/TextView09"
android:text="Price"
android:layout_weight="1"
android:background="#d3d3d3"
android:textColor="#000000"
android:padding="20dip"
android:gravity="center"/>
</TableRow>
</TableLayout>
thank you

Your btn click code should like below:
bBasket.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
EditText Wood = (EditText) findViewById(R.id.Wood);
String str = Wood.getText().toString();
if (str.length() == 0) {
Wood.requestFocus();
Wood.setError("FIELD CANNOT BE EMPTY");
} else if (str.length() >= 2) {
Wood.requestFocus();
Wood.setError("You can only type one letter!");
} else {
Intent intent2 = new Intent(Letters.this, Basket.class);
intent2.putExtra("MY_INFO",str + " - Letters" + price );
TextView price = (TextView) findViewById(R.id.price);
String pri = price.getText().toString();
intent2.putExtra("£",pri);
startActivity(intent2);
}
}
});
Hope this will help you.

On Android emulator my button is not clicking

I'm recently started to program and faced with this problem. My button is not clicking in emulator, however, I wrote onClickListener in java. It still doesn't work.
Here is my xml code:
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Button
android:id="#+id/btn1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="#string/SD"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:layout_marginTop="70dp"
android:background="#color/blue_gray"
android:visibility="visible"
android:onClick="onClick"/>
<Button
android:id="#+id/btn2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="#string/SD2"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:layout_marginTop="70dp"
android:background="#color/follow"
android:visibility="gone"
android:onClick="onClick"/>
</FrameLayout>
Here is my java code:
enter code here
package com;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import com.example.app.R;
/**
* Created by ww on 12.02.14.
*/
public class fragment_main extends Activity {
Button i1;
Button i2;
protected void onCreate (Bundle SavedInstanceState){
super.onCreate(SavedInstanceState);
setContentView(R.layout.fragment_main);
i1= (Button) findViewById(R.id.btn1);
i2=(Button) findViewById(R.id.btn2);
}
public void onClick(View view) {
switch (view.getId()) {
case R.id.btn1:
i1.setVisibility(View.GONE);
i2.setVisibility(View.VISIBLE);
break;
case R.id.btn2:
i1.setVisibility(View.VISIBLE);
i2.setVisibility(View.GONE);
break;
}
}
}

Here's the working code,
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<Button
android:id="#+id/btn1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="#string/sd"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:layout_marginTop="70dp"
android:onClick="onClick"/>
<Button
android:id="#+id/btn2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="#string/sd2"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:layout_marginTop="140dp"
android:visibility="gone"
android:onClick="onClick"/>
</RelativeLayout>
MainActivity.java
package com.example.test;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
Button b1;
Button b2;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1 = (Button) findViewById(R.id.btn1);
b2 = (Button) findViewById(R.id.btn2);
}
public void onClick(View v) {
switch(v.getId()) {
case R.id.btn1:
b2.setVisibility(View.VISIBLE);
b1.setVisibility(View.INVISIBLE);
break;
case R.id.btn2:
b2.setVisibility(View.INVISIBLE);
b1.setVisibility(View.VISIBLE);
break;
}
}
}
Output (Compiled & ran in Emulator):
When the app starts Button2 will be invisible since it was set as invisible in xml layout.
Once the user click button1 above, button2 will be visible & button1 will be invisible.

you have to register a listener to your buttons, e.g.:
i1 = (Button) findViewById(R.id.btn1);
i2 = (Button) findViewById(R.id.btn2);
//inside onCreate do this:
i1.setOnClickListener(myhandler1);
i2.setOnClickListener(myhandler2);
Then you have to create those listeners.
// somewhere outside onCreate do this:
View.OnClickListener myhandler1 = new View.OnClickListener() {
public void onClick(View v) {
// it was the 1st button
}
};
View.OnClickListener myhandler2 = new View.OnClickListener() {
public void onClick(View v) {
// it was the 2nd button
}
};

how to create button on android platform

I created a button in my Android project, but it's not working.
Here is my application (based on 'hello world'):
activity_main.xml
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/container"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<TextView android:id="#+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello, I am a TextView" />
<Button android:id="#+id/button_roy"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello, I am a Button" />
</LinearLayout>
and this is my java roy.java
package aa.aa.aaaaaaa.royb;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
/**
* Created by royb on 05/11/13.
*/
public class roy extends Activity {
public void onCreate (Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button createBtn = (Button) findViewById(R.id.button_roy);
createBtn.setOnClickListener(new View.OnClickListener()
{
public void onClick (View v)
{
Context context = getApplicationContext();
CharSequence text = "Hello toast!";
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
}
});
}
}
When I run it on my android device and click the button it doesn't do anything.
How can I make the toast display?

public class Roy extends Activity
{
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button createBtn = (Button) findViewById(R.id.button_roy);
createBtn.setOnClickListener(new View.OnClickListener()
{
public void onClick (View v)
{
Toast.makeText(getApplicationContext,"HelloToast",Toast.LENGTH_SHORT).show();
}
}
}

Develop Reference

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

Android Button findViewByID returns null - java

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