android onKeyDown(int keyCode, KeyEvent event)

     
     
   
   

      
      
    
     1 
      
      
    
    @Override

      
      
    
     2 
      
      
    
        
      
      
    
    public
      
      
    
     
      
      
    
    boolean
      
      
    
     onKeyDown(
      
      
    
    int
      
      
    
     keyCode, KeyEvent event) {

      
      
    
     3 
      
      
    
            
      
      
    
    //
      
      
    
     TODO Auto-generated method stub
      
      
    
    

      
      
    
     4 
      
      
    
    
      
      
    
            

      
      
    
     5 
      
      
    
            
      
      
    
    if
      
      
    
    (keyCode
      
      
    
    ==
      
      
    
    KeyEvent.KEYCODE_BACK){

      
      
    
     6 
      
      
    
                
      
      
    
    //
      
      
    
    弹出确定退出对话框
      
      
    
    

      
      
    
     7 
      
      
    
    
      
      
    
                
      
      
    
    new
      
      
    
     AlertDialog.Builder(
      
      
    
    this
      
      
    
    )

      
      
    
     8 
      
      
    
                .setTitle(
      
      
    
    "
      
      
    
    退出
      
      
    
    "
      
      
    
    )

      
      
    
     9 
      
      
    
                .setMessage(
      
      
    
    "
      
      
    
    确定退出吗？
      
      
    
    "
      
      
    
    )

      
      
    
    10 
      
      
    
                .setPositiveButton(
      
      
    
    "
      
      
    
    确定
      
      
    
    "
      
      
    
    , 
      
      
    
    new
      
      
    
     DialogInterface.OnClickListener() {

      
      
    
    11 
      
      
    
                    

      
      
    
    12 
      
      
    
                    @Override

      
      
    
    13 
      
      
    
                    
      
      
    
    public
      
      
    
     
      
      
    
    void
      
      
    
     onClick(DialogInterface dialog, 
      
      
    
    int
      
      
    
     which) {

      
      
    
    14 
      
      
    
                        
      
      
    
    //
      
      
    
     TODO Auto-generated method stub
      
      
    
    

      
      
    
    15 
      
      
    
    
      
      
    
                        Intent exit 
      
      
    
    =
      
      
    
     
      
      
    
    new
      
      
    
     Intent(Intent.ACTION_MAIN);

      
      
    
    16 
      
      
    
                        exit.addCategory(Intent.CATEGORY_HOME);

      
      
    
    17 
      
      
    
                        exit.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

      
      
    
    18 
      
      
    
                        startActivity(exit);

      
      
    
    19 
      
      
    
                        System.exit(
      
      
    
    0
      
      
    
    );

      
      
    
    20 
      
      
    
                    }

      
      
    
    21 
      
      
    
                })

      
      
    
    22 
      
      
    
                .setNegativeButton(
      
      
    
    "
      
      
    
    取消
      
      
    
    "
      
      
    
    , 
      
      
    
    new
      
      
    
     DialogInterface.OnClickListener() {

      
      
    
    23 
      
      
    
                    

      
      
    
    24 
      
      
    
                    @Override

      
      
    
    25 
      
      
    
                    
      
      
    
    public
      
      
    
     
      
      
    
    void
      
      
    
     onClick(DialogInterface dialog, 
      
      
    
    int
      
      
    
     which) {

      
      
    
    26 
      
      
    
                        
      
      
    
    //
      
      
    
     TODO Auto-generated method stub
      
      
    
    

      
      
    
    27 
      
      
    
    
      
      
    
                        dialog.cancel();

      
      
    
    28 
      
      
    
                    }

      
      
    
    29 
      
      
    
                })

      
      
    
    30 
      
      
    
                .show();

      
      
    
    31 
      
      
    
                
      
      
    
    //
      
      
    
    这里不需要执行父类的点击事件，所以直接return
      
      
    
    

      
      
    
    32 
      
      
    
    
      
      
    
                
      
      
    
    return
      
      
    
     
      
      
    
    true
      
      
    
    ;

      
      
    
    33 
      
      
    
            }

      
      
    
    34 
      
      
    
            
      
      
    
    //
      
      
    
    继续执行父类的其他点击事件
      
      
    
    

      
      
    
    35 
      
      
    
    
      
      
    
            
      
      
    
    return
      
      
    
     
      
      
    
    super
      
      
    
    .onKeyDown(keyCode, event);

      
      
    
    36 
      
      
    
        }