java.lang.RuntimeException：無法啓動活動ComponentInfo java.lang.ClassCastException

我在寫一個sudoku應用程序。我想製作一個主視圖和拼圖視圖，但是當我完成第二個活動時，它墜毀了。java.lang.RuntimeException：無法啓動活動ComponentInfo java.lang.ClassCastException

這是我的主要活動的onCreate功能：

public class Main extends Activity { 
    private Button button1, button3,button4; 
    PuzzleView puzzleview; 
    Score score; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     puzzleview = new PuzzleView(this); 
     score = new Score(this); 

     setContentView(R.layout.activity_main); 

     button1 = (Button)findViewById(R.id.button1); 
     button1.setOnClickListener(new Button.OnClickListener(){ 
      public void onClick(View v) { 
       setContentView(puzzleview); 
      } 
     }); 

     button4 = (Button)findViewById(R.id.button4); 
     button4.setOnClickListener(new Button.OnClickListener(){ 
      public void onClick(View v) { 
       setContentView(score); 
      } 
     }); 
    }

這是我第二次活動的onCreate：

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

     main = new Main(); 
     puzzleview = new PuzzleView(this); 
     puzzleview.requestFocus(); 
    }

這logcat的：

12-01 20:17:56.291: E/AndroidRuntime(1345): FATAL EXCEPTION: main 
12-01 20:17:56.291: E/AndroidRuntime(1345): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.sudoku/com.example.sudoku.Main}: java.lang.ClassCastException: com.example.sudoku.Main cannot be cast to com.example.sudoku.Sudoku 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.app.ActivityThread.access$600(ActivityThread.java:130) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.os.Handler.dispatchMessage(Handler.java:99) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.os.Looper.loop(Looper.java:137) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.app.ActivityThread.main(ActivityThread.java:4745) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at java.lang.reflect.Method.invokeNative(Native Method) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at java.lang.reflect.Method.invoke(Method.java:511) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at dalvik.system.NativeStart.main(Native Method) 
12-01 20:17:56.291: E/AndroidRuntime(1345): Caused by: java.lang.ClassCastException: com.example.sudoku.Main cannot be cast to com.example.sudoku.Sudoku 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at com.example.sudoku.PuzzleView.<init>(PuzzleView.java:26) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at com.example.sudoku.Main.onCreate(Main.java:18) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.app.Activity.performCreate(Activity.java:5008) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023) 
12-01 20:17:56.291: E/AndroidRuntime(1345):  ... 11 more

如果有任何信息不夠了，請告訴我，謝謝。

來源

2012-12-01 CYB

dmon是正確的關於這個LogCat的錯誤的位置。但是我想指出一些其他的東西：你不應該使用'main = new Main（）;'來創建一個Activity，這會導致很多錯誤。 – Sam

的問題是沒有在任何您張貼位，但在PuzzleView 26行：

at com.example.sudoku.PuzzleView.<init>(PuzzleView.java:26)

你想投你傳遞什麼，一個Main情況下，成(Sudoku)。

來源

2012-12-01 20:39:18 dmon

java.lang.RuntimeException：無法啓動活動ComponentInfo java.lang.ClassCastException

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