android开发 退出程序

原文地址：http://blog.csdn.net/dyllove98/article/details/8831948

贴代码：

public void exitclick(View view)
    {
        AlertDialog.Builder aa=new AlertDialog.Builder(this); 
        aa.setTitle("消息提示");
        aa.setMessage("确认退出？"); 
        aa.setIcon(R.drawable.icon);
        aa.setPositiveButton("确定",new DialogInterface.OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                MainActivity.this.finish();
            }
        });
        aa.setNegativeButton("取消", null);
        aa.create(); 
        aa.show(); 

        //this.finish();
    }

还有就是按返回键提示退出，继续贴代码：

private void exitDialog()
    {
        AlertDialog.Builder aa=new AlertDialog.Builder(this); 
        aa.setTitle("消息提示");
        aa.setMessage("确认退出？"); 
        aa.setIcon(R.drawable.icon);
        aa.setPositiveButton("确定",new DialogInterface.OnClickListener() {
            
            @Override
            public void onClick(DialogInterface dialog, int which) {
                // TODO Auto-generated method stub
                MainActivity.this.finish();
            }
        });
        aa.setNegativeButton("取消", null);
        aa.create(); 
        aa.show(); 
    }
    
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event)
    {
        if(keyCode == KeyEvent.KEYCODE_BACK)
        {
        exitDialog();
        }
        return true;
        
    }

现在还流行连续按两次返回退出，代码：

    /*此段代码有误，
　　private static boolean isExit=false;
    private static boolean hasTask=false;
    Timer tExit=new Timer();
    TimerTask task=new TimerTask() {
        
        @Override
        public void run() {
            // TODO Auto-generated method stub
            isExit=false;
            hasTask=false;
        }
    };


@Override
    public boolean onKeyDown(int keyCode, KeyEvent event)
    {
        if(keyCode == KeyEvent.KEYCODE_BACK)
        {
            //exitDialog();
            if(isExit==false)
            {
                isExit=true;
                Toast.makeText(this, "再按一次退出程序", Toast.LENGTH_SHORT).show(); 
                if(!hasTask) {
                    tExit.schedule(task, 2000);
                }
            }
            else
            {
                finish();
                System.exit(0);
            }
            
        }
        //return true;
        return false;
        
    }*/

1. 设置外部变量private static Boolean isExit = false; 

2. 添加下列函数到Main Activity中

public boolean onKeyDown(int keyCode, KeyEvent event) {
  // TODO Auto-generated method stub
  if(keyCode == KeyEvent.KEYCODE_BACK);
  {
   exitBy2Click();     
  }
  return false;
 }

 private void exitBy2Click() {
  // TODO Auto-generated method stub
  Timer tExit = null; 
  if (isExit == false) { 
    isExit = true; // 准备退出 
          Toast.makeText(this, "Press Back again to quit", Toast.LENGTH_SHORT).show(); 
          tExit = new Timer(); 
          tExit.schedule(new TimerTask() {  
              public void run() { 
                 isExit = false; // 取消退出 
              } 
          }, 2000); // 如果2秒钟内没有按下返回键，则启动定时器取消掉刚才执行的任务 
   
  }
  
  else { 
          finish(); 
         System.exit(0); 
  } 

 }