I have just started working on Android Studio and I am not able to solve this problem. I Have been getting the uploaded errors for a long time. Here are the files I am using. I have checked the package name as well, so that is not the issue.
MainAcitivity.java
package com.example.android.justjava;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
/**
* This app displays an order form to order coffee.
*/
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
/**
* This method is called when the order button is clicked.
*/
public void submitOrder(View view) {
display(1);
}
/**
* This method displays the given quantity value on the screen.
*/
private void display(int number) {
TextView quantityTextView = (TextView) findViewById(
R.id.quantity_text_view);
quantityTextView.setText("" + number);
}
}
activity_main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="16dp"
android:orientation="vertical"
tools:context=".MainActivity">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
android:text="Quantity"
android:textAllCaps="true" />
<TextView
android:id="#+id/quantity_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:textColor="#000000"
android:textSize="16sp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="16dp"
android:text="Order"
android:textAllCaps="true"
android:onClick="submitOrder" />
</LinearLayout>
Error messages
You probably didn't add the appropriate support lib dependency. Add the following line to the dependencies block in your module's build.gradle file:
compile 'com.android.support:appcompat-v7:24.2.0'
You should also read the Support Library Setup before using the support libs.
Related
I am new to android dev and started learning from udacity course but the java code is not running It is showing errors(picture below). I am new at stack overflow too sorry I don't know how to properly post a question.
the java program(image to know the errors)
https://drive.google.com/file/d/1D-OSZX2oxuRWZD_Yb8x4WWUBhMykWQKq/view?usp=sharing
package com.example.justjava;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
/**
* This app displays an order form to order coffee.
*/
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
/**
* This method is called when the order button is clicked.
*/
public void submitOrder(View view) {
display(1);
}
/**
* This method displays the given quantity value on the screen.
*/
private void display(int number) {
TextView quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
quantityTextView.setText("" + number);
}
}`
the XML code`
<RelativeLayout 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/quantity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Quantity:"
android:padding="15dp"
/>
<TextView
android:id="#+id/quantity_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:layout_below="#id/quantity"
android:paddingLeft="30dp"
/>
<Button
android:layout_width="wrap_content"
android:layout_height="50dp"
android:layout_marginLeft="5dp"
android:layout_below="#id/quantity_text_view"
android:onClick="submitOrder"
android:text="Order"/>
</RelativeLayout>`
enter image description here
v7 is no longer supported. Instead of v7 use androidx packages.
import androidx.appcompat.app.AppCompatActivity;
I am making a simple app in which context view changes and then a toast message is displayed as input given by user. I don't understand why the app keeps on crashing when changing the context view.
Also Android studio gives this warning:
Method "Toaster" is missing in "FirstActivity" or has incorrect signature.
Here is my code:
activity_me_clicked.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="#string/welcome"
android:textSize="36sp" />
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="15dp"
android:paddingLeft="7dp"
android:paddingRight="7dp"
android:text="#string/intro"
android:textSize="24sp" />
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:baselineAligned="false">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="vertical">
<EditText
android:id="#+id/name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="7dp"
android:layout_marginEnd="7dp"
android:layout_marginTop="10dp"
android:ems="10"
android:hint="Name"
android:inputType="textPersonName"
tools:ignore="HardcodedText" />
<Button
android:id="#+id/named"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:paddingBottom="10dp"
android:paddingTop="10dp"
android:onClick="MainProcess"
android:text="#string/done" />
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="horizontal"
tools:ignore="UselessLeaf"></LinearLayout>
</LinearLayout>
</LinearLayout>
FirstActivity.Java:
package com.example.nautatvanavlakha.abcd;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
public class FirstActivity extends AppCompatActivity {
public static String owner_string;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_me_clicked);
}
public void MainProcess(View view) {
final String TAG="DEBUG";
Log.d(TAG,"At least process started");
EditText owner = (EditText) findViewById(R.id.name);
owner_string = owner.getText().toString();
Log.d(TAG,"owner name stored");
TextView textView = (TextView) findViewById(R.id.welcome);
textView.setText("Hi " + owner_string + ".");
Log.d(TAG,"owner name is set");
setContentView(R.layout.activity_main_screen);
Log.d(TAG,"content shown");
}
}
activity_main_screen.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="#+id/welcome"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
<TextView
android:id="#+id/textView4"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="#string/what_would_you_like_me_to_do_today"
android:textSize="18sp" />
<Button
android:id="#+id/Cam"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:padding="0dp"
android:paddingTop="15dp"
android:text="#string/camera" />
<Button
android:id="#+id/Mus"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:padding="0dp"
android:paddingTop="15dp"
android:text="#string/music" />
<Button
android:id="#+id/QR"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:padding="0dp"
android:paddingTop="15dp"
android:text="#string/scanQR" />
<EditText
android:id="#+id/toastText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:ems="10"
android:hint="#string/order"
android:inputType="textPersonName" />
<Button
android:id="#+id/toaster"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="15dp"
android:layout_marginRight="15dp"
android:onClick="toaster"
android:padding="0dp"
android:paddingTop="15dp"
android:text="#string/toast"
android:layout_marginEnd="100dp"
android:layout_gravity="center"/>
</LinearLayout>
MainScreen.java:
package com.example.nautatvanavlakha.abcd;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
public class MainScreen extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_screen);
}
public void toaster(View view){
EditText toast = (EditText)findViewById(R.id.toastText);
String final_toast = toast.getText().toString();
Toast.makeText(getApplicationContext(), final_toast, Toast.LENGTH_SHORT).show();
}
}
EDIT: As suggested, I moved the toaser function to FirstActivity.Java and deleted the MainScreen.java file as it becomes pointless to keep it. But the major problem is when I press the button (id named) the app keeps stopping.
EDIT2: I found that setContentView(R.layout.activity_main_screen) in FirstActivity.Java needs to be above this code
TextView textView = (TextView) findViewById(R.id.welcome);
textView.setText("Hi " + owner_string + ".");
Log.d(TAG,"owner name is set");
so that Activity has access to all the layout components. Thanks solved :)
You replaced the content view in the first activity with a layout that include the onClick attribute, but you have no public void toaster(View view) method there.
So, either don't use setContentView a second time, or implement that method on both Activities.
The recommended way to replace the view is Fragments, by the way
This is a wrong way to change the contents of your Activity, The main problem here is that you have onClick attribute set to "toaster", And you don't have a function called "toaster" in your FirstActivity.
Beside that, The MainScreen Activity in your code will never be used.
So, Your problem is that you set the FirstActivity contents to "activity_main_screen.xml", And FirstActivity doesn't have "toaster" method in it, When you change the context, the Activity will try to find toaster method and the app will crash because the method doesn't exist in FirstActivity.
You can solve this problem by making a method called "toaster" inside FirstActivity, But
This is a very bad practice, You can use Fragments instead, Or you can use Intent to move to another activity.
Some useful links about Fragments:
https://developer.android.com/guide/components/fragments.html
https://www.tutorialspoint.com/android/android_fragments.htm
https://examples.javacodegeeks.com/android/core/app/fragment/android-fragments-example/
Why should I use fragment in Android?
My XML code is as follows:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="16dp"
tools:context="com.example.dell.myapplication.MainActivity"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="QUANTITY"
android:paddingBottom="8dp"/>
<TextView
android:id="#+id/quantity_text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="0"
android:paddingTop="8dp"
android:paddingBottom="8dp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="ORDER"
android:paddingTop="8dp"
android:paddingBottom="8dp"
android:onClick="submitOrder"/>
</LinearLayout>
My JAVA code is as follows:
package com.example.android.justjava;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.TextView;
import com.example.dell.myapplication.R;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
/**
* This method is called when the order button is clicked.
*/
public void submitOrder(View view) {
display(1);
}
/**
* This method displays the given quantity value on the screen.
*/
private void display(int number) {
TextView quantityTextView = (TextView) findViewById(
R.id.quantity_text_view);
quantityTextView.setText("" + number);
}
}
I am not getting any error on Android studio IDE but on uploading the APK file on my phone, it says "Application Error Unfortunately, My Application has stopped."
How do I rectify this? Please help.
Thanks in advance
I am trying to make a simple Planner app so I have an XML file with a ListView on it, and another XML file with an EditText and a sumbit button on it, and of course my Java files. I have done a ton of research but I can't find a working method to make it when I press the button, it adds the EditText stuff to the ListView as an item. Here is my code:
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<ListView
android:layout_width="300dp"
android:layout_height="fill_parent"
android:id="#+id/event_list"
android:layout_alignParentStart="true"
android:layout_toStartOf="#+id/datePicker" />
<DatePicker
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/datePicker"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true" />
<CalendarView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/calendarView"
android:layout_alignBottom="#+id/datePicker"
android:layout_alignParentEnd="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Event"
android:id="#+id/button"
android:layout_centerVertical="true"
android:layout_alignEnd="#+id/datePicker"
android:layout_toEndOf="#+id/event_list"
android:background="#android:color/holo_blue_light"
android:onClick="newEvent"
android:textSize="20dp"
android:textColor="#android:color/white" />
</RelativeLayout>
new_plan.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:weightSum="1">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/event_name"
android:hint="Event Name"
android:inputType="textCapWords"/>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/event_date"
android:hint="Event Date" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Save"
android:id="#+id/button2"
android:layout_gravity="center_horizontal"
android:background="#android:color/holo_blue_light"
android:textSize="20dp"
android:textColor="#android:color/white" />
</LinearLayout>
MakePlan.java
package com.kass.planner;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
public class MakePlan extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.new_plan);
}
}
MainActivity.java
package com.kass.planner;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void newEvent(View v){
Intent i = new Intent(this, MakePlan.class);
startActivity(i);}}
Please help, thank you.
Take a look on this google developers project. It's for animations but i think it also have the solution to your question.
https://developer.android.com/training/animation/layout.html
You should append data to the collection of items linked to your ListView via your adapter and notify your adapter that your data has changed. This illustration assumes that you have a List of String objects.
EditText editText = ...
List<String> list = ...
YourAdapter adapter = ...
ListView listView = ...
You must have done something like this to setup your listView.
listView.setAdapter(new YourAdapter(list, this));
Now on button click you should get the String in EditText, add it to your List and finally notify the adapter that your data has changed in order to update your ListView for e.g.
void OnButtonClick(View view){
String strToAdd = editText.getText().toString();
list.add(strToAdd);
adapter.notifyDataSetChanged();
}
So I have an ImageView in my xml file that is an image I created. The id of it is gameplayTop. In my java file for that activity, I try to set a variable to set that imageview, but then when I start up my emulator it says "Error: cannot find symbol variable gameTop".
Here is my xml file:
<?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="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.ics466.brainscrew.GameplayActivity"
android:background="#color/background">
<Chronometer
android:layout_width="100dp"
android:layout_height="wrap_content"
android:id="#+id/chronometer"
android:layout_centerHorizontal="true" />
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/gameplay_Area"
android:src="#drawable/playarea"
android:layout_alignParentTop="true"
android:layout_alignParentEnd="true" />
<ImageView
android:layout_width="100dp"
android:layout_height="250dp"
android:id="#+id/gameLeft"
android:src="#drawable/gameplay_left_blue"
android:layout_alignParentStart="true"
android:layout_centerVertical="true" />
<ImageView
android:layout_width="250dp"
android:layout_height="100dp"
android:id="#+id/gameTop"
android:src="#drawable/gameplay_top_blue"
android:maxWidth="250dp"
android:maxHeight="95dp"
android:layout_marginTop="120dp"
android:layout_below="#+id/chronometer"
android:layout_centerHorizontal="true"
android:layout_gravity="right" />
</RelativeLayout>
And here is my javacode (with stuff cut out, but mainly I'm concerned with my imageview)
import android.media.Image;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
public class GameplayActivity extends AppCompatActivity {
ImageView top, bot, left, right;
String message;
private android.widget.RelativeLayout.LayoutParams layoutParams;
/**
* Sets the screen layout and sets this screen to fullscreen-mode.
*
* #param savedInstanceState saved previous state.
*/
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_gameplay);
top = (ImageView) findViewById(R.id.gameTop);
Random rnd = new Random(2);
int colorIndex = rnd.nextInt(8);
makeBorders(rand4());
}
Do I need to do something else to have it recognize the id?
Check your Xml files, and make sure they are properly closed />