Android返回键的监听汇总

Android返回键的监听汇总

一，返回键的简单监听

	@Override
	public void onBackPressed() {
		Toast.makeText(this, "你点击了返回键", 0).show();
	}

二，双击退出

	// 返回键的监听
	private Boolean isExit = false;

	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		if (keyCode == KeyEvent.KEYCODE_BACK) {
			exitByDoubleClick();
		}

		return false;
	}

	private void exitByDoubleClick() {
		Timer tExit = null;
		if (isExit == false) {
			isExit = true;
			Toast.makeText(this, "再按一下,退出", Toast.LENGTH_SHORT).show();
			tExit = new Timer();
			tExit.schedule(new TimerTask() {
				@Override
				public void run() {
					isExit = false;
				}
			}, 2000);
		} else {
			android.os.Process.killProcess(android.os.Process.myPid());
		}
	}

三，弹出一个退出对话框

public class BackKeyTest extends Activity  
{  
    /** Called when the activity is first created. */  
    @Override  
    public void onCreate(Bundle savedInstanceState)  
    {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.main);  
  
    }  
      
    @Override  
    public boolean onKeyDown(int keyCode, KeyEvent event)  
    {  
        if (keyCode == KeyEvent.KEYCODE_BACK )  
        {  
            // 创建退出对话框  
            AlertDialog isExit = new AlertDialog.Builder(this).create();  
            // 设置对话框标题  
            isExit.setTitle("系统提示");  
            // 设置对话框消息  
            isExit.setMessage("确定要退出吗");  
            // 添加选择按钮并注册监听  
            isExit.setButton("确定", listener);  
            isExit.setButton2("取消", listener);  
            // 显示对话框  
            isExit.show();  
  
        }  
          
        return false;  
          
    }  
    /**监听对话框里面的button点击事件*/  
    DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener()  
    {  
        public void onClick(DialogInterface dialog, int which)  
        {  
            switch (which)  
            {  
            case AlertDialog.BUTTON_POSITIVE:// "确认"按钮退出程序  
                finish();  
                break;  
            case AlertDialog.BUTTON_NEGATIVE:// "取消"第二个按钮取消对话框  
                break;  
            default:  
                break;  
            }  
        }  
    };    
}