Как мне заставить MyFirstApp работать в Android Studio? ⇐ JAVA

[Anonymous]

Я новичок в Android Studio и пытаюсь запустить мое первое приложение. Функция Hello World работает нормально, но приложение закрывается всякий раз, когда я нажимаю кнопку «Отправить во втором приложении». /> mainactivity.java
package com.example.myfirstapp;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

import static android.provider.AlarmClock.EXTRA_MESSAGE;

public class MainActivity extends AppCompatActivity {
public static final String EXTRA_MESSAGE = "com.example.myfirstapp.MESSAGE";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}

/** Called when the user taps the Send button */
public void sendMessage(View view) {
Intent intent = new Intent(this, DisplayMessageActivity.class);
EditText editText = (EditText) findViewById(R.id.edit_message);
String message = editText.getText().toString();
intent.putExtra(EXTRA_MESSAGE, message);
startActivity(intent);
}
}
< /code>
displaymessageactivity.java
package com.example.myfirstapp;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.os.Bundle;
import android.widget.TextView;

public class DisplayMessageActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_message);

// Get the Intent that started this activity and extract the string
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);

// Capture the layout's TextView and set the string as its text
TextView textView = findViewById(R.id.textView);
textView.setText(message);
}
}
< /code>
android manifest.xml:


















< /code>
Любая справка очень ценится!2021-06-22 13:36:31.716 6345-6345/com.example.myfirstapp E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.myfirstapp, PID: 6345
java.lang.IllegalStateException: Could not execute method for android:onClick
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:414)
at android.view.View.performClick(View.java:7352)
at android.widget.TextView.performClick(TextView.java:14230)
at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992)
at android.view.View.performClickInternal(View.java:7318)
at android.view.View.access$3200(View.java:846)
at android.view.View$PerformClick.run(View.java:27800)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7050)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invoke(Native Method)
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409)
at android.view.View.performClick(View.java:7352) 
at android.widget.TextView.performClick(TextView.java:14230) 
at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992) 
at android.view.View.performClickInternal(View.java:7318) 
at android.view.View.access$3200(View.java:846) 
at android.view.View$PerformClick.run(View.java:27800) 
at android.os.Handler.handleCallback(Handler.java:873) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:214) 
at android.app.ActivityThread.main(ActivityThread.java:7050) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965) 
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
at com.example.myfirstapp.MainActivity.sendMessage(MainActivity.java:24)
at java.lang.reflect.Method.invoke(Native Method) 
at androidx.appcompat.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:409) 
at android.view.View.performClick(View.java:7352) 
at android.widget.TextView.performClick(TextView.java:14230) 
at com.google.android.material.button.MaterialButton.performClick(MaterialButton.java:992) 
at android.view.View.performClickInternal(View.java:7318) 
at android.view.View.access$3200(View.java:846) 
at android.view.View$PerformClick.run(View.java:27800) 
at android.os.Handler.handleCallback(Handler.java:873) 
at android.os.Handler.dispatchMessage(Handler.java:99) 
at android.os.Looper.loop(Looper.java:214) 
at android.app.ActivityThread.main(ActivityThread.java:7050) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965) 
2021-06-22 13:36:31.777 6345-6345/com.example.myfirstapp I/Process: Sending signal. PID: 6345 SIG: 9
< /code>
Aactivity_main.xml







< /code>
Aactivity_display_message.xml







Подробнее здесь: https://stackoverflow.com/questions/680 ... oid-studio