android 返回鍵徹底退出程序

主頁面中覆蓋onKeyDown方法
   
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        // TODO Auto-generated method stub
        if(keyCode == KeyEvent.KEYCODE_BACK){
            ShowDialog.showExitDialog(MainActivity.this);
        }
        return true;
    }






ShowDialog.java

public class ShowDialog{
   
   
    public static void showExitDialog(Activity context){
        //實例化一個關於退出的警示對話框
        final AlertDialog exitDialog = new AlertDialog.Builder(context).create();
        exitDialog.setTitle("提示");
        exitDialog.setMessage("是否退出程序");
       
        //點擊「是」的時候觸發的事件
        exitDialog.setButton("是", new AlertDialog.OnClickListener(){

            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                exitDialog.dismiss();
                System.out.println("the wopai program exit");
                System.exit(0);
               
            }
           
        });
       
        //點擊「否」的時候觸發的事件
        exitDialog.setButton2("否", new AlertDialog.OnClickListener(){

            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                exitDialog.dismiss();
            }
           
        });
        //顯示對話框
        exitDialog.show();
    }
   
}