無法在Android應用程序的對話框中設置OnClickListener

Question

我無法在Android應用程序的對話框中設置OnClickListener。它完成了一個錯誤。日誌是：

01-10 12:35:45.792: ERROR/AndroidRuntime(918): FATAL EXCEPTION: main 
01-10 12:35:45.792: ERROR/AndroidRuntime(918): java.lang.NullPointerException 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.htmleditor.MainActivity.onCreateDialog(MainActivity.java:169) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.app.Activity.onCreateDialog(Activity.java:2482) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.app.Activity.createDialog(Activity.java:882) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.app.Activity.showDialog(Activity.java:2557) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.app.Activity.showDialog(Activity.java:2524) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.htmleditor.MainActivity$2.onClick(MainActivity.java:106) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.view.View.performClick(View.java:2485) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.view.View$PerformClick.run(View.java:9080) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.os.Handler.handleCallback(Handler.java:587) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.os.Handler.dispatchMessage(Handler.java:92) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.os.Looper.loop(Looper.java:123) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at android.app.ActivityThread.main(ActivityThread.java:3647) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at java.lang.reflect.Method.invokeNative(Native Method) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at java.lang.reflect.Method.invoke(Method.java:507) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
01-10 12:35:45.792: ERROR/AndroidRuntime(918):  at dalvik.system.NativeStart.main(Native Method) 
01-10 12:35:48.002: ERROR/InputDispatcher(67): channel '4065a710 android.htmleditor/android.htmleditor.MainActivity (server)' ~ Consumer closed input channel or an error occurred. events=0x8 
01-10 12:35:48.012: ERROR/InputDispatcher(67): channel '4065a710 android.htmleditor/android.htmleditor.MainActivity (server)' ~ Channel is unrecoverably broken and will be disposed! 

我有兩個版本的代碼。他們兩人挑起的錯誤

MainActivity，功能的onCreate（）

insertImage.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View v) { 

        Dialog dialog = new Dialog(MainActivity.this); 
        dialog.setContentView(R.layout.dialogimage); 
        dialog.setTitle("Insert image"); 
        final EditText fieldForURL = (EditText)findViewById(R.id.fieldForURL); 
        Button on = (Button)findViewById(R.id.okImage); 
        on.setOnClickListener(new OnClickListener() { 

         @Override 
         public void onClick(View v) { 
          visualPane.getText().insert(visualPane.getSelectionEnd(),"<img src=\"" + fieldForURL.getText().toString() + "\">"); 

         } 
        }); 
        dialog.setCancelable(true); 
        dialog.show(); 


       //showDialog(IDD_CUSTOM_INSERT_IMAGE); 

      } 
     }); 

或功能OnCreateDialog（）

@Override 
protected Dialog onCreateDialog(int id) { 
    LayoutInflater inflater = (LayoutInflater) this.getSystemService(LAYOUT_INFLATER_SERVICE); 
    AlertDialog.Builder alert = new AlertDialog.Builder(this); 

    alert.setTitle("Create table"); 
    alert.setCancelable(false); 

    Dialog dialog = null; 
    dialog = new Dialog(this); 
    switch (id) { 
     case IDD_CUSTOM_INSERT_TABLE: 

      dialog.setTitle("Insert table"); 
      dialog.setContentView(R.layout.dialogtable); 

      okTableDialog = (Button)findViewById(R.id.okTable); 
      cancelTableDialog = (Button)findViewById(R.id.okTable); 
      fieldForRows = (EditText)findViewById(R.id.entry01); 
      fieldForColumns = (EditText)findViewById(R.id.entry02); 
      fieldForWidthOfBroder = (EditText)findViewById(R.id.fieldForBorder); 
      okTableDialog.setOnClickListener(new OnClickListener() { 

        @Override 
        public void onClick(View v) { 
         TableAction tablAc = new TableAction(visualPane); 
         tablAc.insertTable(fieldForRows.getText().toString(),fieldForColumns.getText().toString(), fieldForWidthOfBroder.getText().toString()); 
        } 
       }); 

      return dialog; 
     case IDD_CUSTOM_INSERT_IMAGE: 
      dialog.setTitle("Insert image"); 
      dialog.setContentView(R.layout.dialogimage); 

      final EditText fieldForURL = (EditText)findViewById(R.id.fieldForURL); 
      Button on = (Button)findViewById(R.id.okImage); 
      on.setOnClickListener(new OnClickListener() { 

        @Override 
        public void onClick(View v) { 
         visualPane.getText().insert(visualPane.getSelectionEnd(),"<img src=\"" + fieldForURL.getText().toString() + "\">"); 

        } 
       }); 

      return dialog; 
     default: 
      return alert.create(); 
    } 
} 

如果我在這兩種情況下注釋掉 「setOnClickListener」 時，PROGRAMM會不完成一個錯誤

請幫助，爲什麼會發生？

Answer 1

您正在搜索的按鈕不是正確的對象。試試這個：

Button on = (Button)dialog.findViewById(R.id.okImage);