無法啓動活動componentinfo +您的應用程序已意外停止。請再試一次

Question

請幫助我。我是初學者在android.i有一個Android應用程序。 我有一個按鈕，並編輯文本，我想我寫在文本中的每一件事，發送到putextra另一個頁面，並顯示在textView.but但當我點擊這個buttom我的應用程序停止並說：sorry.application意外停止。請再試一次。謝謝你的關注。 這是log貓錯誤：

08-16 17:17:30.001: E/AndroidRuntime(736): FATAL EXCEPTION: main 
08-16 17:17:30.001: E/AndroidRuntime(736): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.secondapplicationandroid/com.example.secondapplicationandroid.dovomi}: java.lang.NullPointerException 
08-16 17:17:30.001: E/AndroidRuntime(736): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 
08-16 17:17:30.001: E/AndroidRuntime(736): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 
08-16 17:17:30.001: E/AndroidRuntime(736): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
08-16 17:17:30.001: E/AndroidRuntime(736): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 
08-16 17:17:30.001: E/AndroidRuntime(736): at android.os.Handler.dispatchMessage(Handler.java:99) 
08-16 17:17:30.001: E/AndroidRuntime(736): at android.os.Looper.loop(Looper.java:123) 
08-16 17:17:30.001: E/AndroidRuntime(736): at android.app.ActivityThread.main(ActivityThread.java:3683) 
08-16 17:17:30.001: E/AndroidRuntime(736): at java.lang.reflect.Method.invokeNative(Native Method) 
08-16 17:17:30.001: E/AndroidRuntime(736): at java.lang.reflect.Method.invoke(Method.java:507) 
08-16 17:17:30.001: E/AndroidRuntime(736): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
08-16 17:17:30.001: E/AndroidRuntime(736): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
08-16 17:17:30.001: E/AndroidRuntime(736): at dalvik.system.NativeStart.main(Native Method) 
08-16 17:17:30.001: E/AndroidRuntime(736): Caused by: java.lang.NullPointerException 
08-16 17:17:30.001: E/AndroidRuntime(736): at com.example.secondapplicationandroid.dovomi.onCreate(dovomi.java:14) 
08-16 17:17:30.001: E/AndroidRuntime(736): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
08-16 17:17:30.001: E/AndroidRuntime(736): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 
08-16 17:17:30.001: E/AndroidRuntime(736): ... 11 more 
08-16 17:17:33.012: I/Process(736): Sending signal. PID: 736 SIG: 9 
08-16 17:21:48.723: W/KeyCharacterMap(778): No keyboard for id 0 
08-16 17:21:48.723: W/KeyCharacterMap(778): Using default keymap: /system/usr/keychars/qwerty.kcm.bin 
08-16 17:21:49.891: D/AndroidRuntime(778): Shutting down VM 
08-16 17:21:49.891: W/dalvikvm(778): threadid=1: thread exiting with uncaught exception (group=0x40015560) 
08-16 17:21:49.921: E/AndroidRuntime(778): FATAL EXCEPTION: main 
08-16 17:21:49.921: E/AndroidRuntime(778): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.secondapplicationandroid/com.example.secondapplicationandroid.dovomi}: java.lang.NullPointerException 
08-16 17:21:49.921: E/AndroidRuntime(778): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647) 
08-16 17:21:49.921: E/AndroidRuntime(778): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 
08-16 17:21:49.921: E/AndroidRuntime(778): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 
08-16 17:21:49.921: E/AndroidRuntime(778): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 
08-16 17:21:49.921: E/AndroidRuntime(778): at android.os.Handler.dispatchMessage(Handler.java:99) 
08-16 17:21:49.921: E/AndroidRuntime(778): at android.os.Looper.loop(Looper.java:123) 
08-16 17:21:49.921: E/AndroidRuntime(778): at android.app.ActivityThread.main(ActivityThread.java:3683) 
08-16 17:21:49.921: E/AndroidRuntime(778): at java.lang.reflect.Method.invokeNative(Native Method) 
08-16 17:21:49.921: E/AndroidRuntime(778): at java.lang.reflect.Method.invoke(Method.java:507) 
08-16 17:21:49.921: E/AndroidRuntime(778): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
08-16 17:21:49.921: E/AndroidRuntime(778): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
08-16 17:21:49.921: E/AndroidRuntime(778): at dalvik.system.NativeStart.main(Native Method) 
08-16 17:21:49.921: E/AndroidRuntime(778): Caused by: java.lang.NullPointerException 
08-16 17:21:49.921: E/AndroidRuntime(778): at com.example.secondapplicationandroid.dovomi.onCreate(dovomi.java:21) 
08-16 17:21:49.921: E/AndroidRuntime(778): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 
08-16 17:21:49.921: E/AndroidRuntime(778): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 
08-16 17:21:49.921: E/AndroidRuntime(778): ... 11 more 
08-16 17:26:50.131: I/Process(778): Sending signal. PID: 778 SIG: 9 

好的。 一個我的MainActivity.java是：

package com.example.secondapplicationandroid; 

import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.EditText; 

public class MainActivity extends Activity { 

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

     Button b= (Button) findViewById(R.id.button2); 
     final EditText matn = (EditText) findViewById(R.id.editText1); 
     b.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View v) { 
       // TODO Auto-generated method stub 
       String s=matn.getText().toString(); 
       Intent mafhoom=new Intent(MainActivity.this, dovomi.class); 
       mafhoom.putExtra("varedshode", s); 
       startActivity(mafhoom); 
       //startActivity(new Intent(MainActivity.this, dovomi.class)); 
      }//end onclick 
     }); 

    }//end void onCreate 


    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.main, menu); 
     return true; 
    } 

} 

and my second page that named is,dovomi.java is: 

package com.example.secondapplicationandroid; 

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

public class dovomi extends Activity { 

    @Override 

    protected void onCreate(Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     super.onCreate(savedInstanceState); 
     TextView matni=(TextView) findViewById(R.id.textView2); 
     Intent iin= getIntent(); 
     Bundle b = iin.getExtras(); 
     if(b!=null) 
     { 
      String j =(String) b.get("varedshode"); 
      matni.setText(j); 
     } 

     //matni.setText(getIntent().getExtras().getString("varedshode")); 
     setContentView(R.layout.dovomi); 
    } 
} 

和清單是：

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.example.secondapplicationandroid" 
    android:versionCode="1" 
    android:versionName="1.0" > 

    <uses-sdk 
     android:minSdkVersion="8" 
     android:targetSdkVersion="16" /> 

    <application 
     android:allowBackup="true" 
     android:icon="@drawable/ic_launcher" 
     android:label="@string/app_name" 
     android:theme="@style/AppTheme" > 
     <activity 
      android:name="com.example.secondapplicationandroid.MainActivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity android:name=".dovomi"></activity> 
    </application> 

</manifest> 

和層，dovomi.xml：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/button3" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" > 

    <TextView 
     android:id="@+id/textView1" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="@string/salam" /> 

    <TextView 
     android:id="@+id/textView2" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:text="TextView" /> 

</LinearLayout> 

Answer 1

的問題是線TextView matni=(TextView) findViewById(R.id.textView2);

在調用findViewById的活動中未指定視圖檢查是當前活動的setContentView視圖。問題是您撥打後致電setContentView(R.layout.dovomi);。

只要確保在撥打任何findViewById電話號碼之前致電setContentView()即可。

因此，在你第二類只是把setContentView(R.layout.dovomi);的super.onCreate(savedInstanceState);