Android实现计时与倒计时(限时抢购)的几种方法

在购物网站的促销活动中一般都有倒计时限制购物时间或者折扣的时间,这些都是如何实现的呢?

在一个安卓客户端项目中恰好遇到了类似的问题，一开始使用的是Timer与 TimerTask, 虽然此方法通用，但后来考虑在安卓中是否有更佳的方案，于是乎共找到以下五种实现方案，另外还有一种使用CountDownTimer进行计时的方面，我会在单独的文章中进行介绍

效果如图:

方法一

public class timerTask extends Activity{  
 
    private int recLen = 11;  
    private TextView txtView;  
    Timer timer = new Timer();  
 
    public void onCreate(Bundle savedInstanceState){  
        super.onCreate(savedInstanceState);  
          
        setContentView(R.layout.timertask);  
        txtView = (TextView)findViewById(R.id.txttime);  
          
        timer.schedule(task, 1000, 1000);       // timeTask  
    }     
 
    TimerTask task = new TimerTask() {  
        @Override  
        public void run() {  
 
            runOnUiThread(new Runnable() {      // UI thread  
                @Override  
                public void run() {  
                    recLen--;  
                    txtView.setText(""+recLen);  
                    if(recLen < 0){  
                        timer.cancel();  
                        txtView.setVisibility(View.GONE);  
                    }  
                }  
            });  
        }  
    };  
}  

public class timerTask extends Activity{  
    private int recLen = 11;  
    private TextView txtView;  
    Timer timer = new Timer();  
 
    public void onCreate(Bundle savedInstanceState){  
        super.onCreate(savedInstanceState);  
 
        setContentView(R.layout.timertask);  
        txtView = (TextView)findViewById(R.id.txttime);  
 
        timer.schedule(task, 1000, 1000);       // timeTask  
    }     
 
    final Handler handler = new Handler(){  
        @Override  
        public void handleMessage(Message msg){  
            switch (msg.what) {  
            case 1:  
                txtView.setText(""+recLen);  
                if(recLen < 0){  
                    timer.cancel();  
                    txtView.setVisibility(View.GONE);  
                }  
            }  
        }  
    };  
 
    TimerTask task = new TimerTask() {  
        @Override  
        public void run() {  
            recLen--;  
            Message message = new Message();  
            message.what = 1;  
            handler.sendMessage(message);  
        }  
    };  
}  

Handler与Message（不用TimerTask）

public class timerTask extends Activity{  
    private int recLen = 11;  
    private TextView txtView;  
 
    public void onCreate(Bundle savedInstanceState) {    
        super.onCreate(savedInstanceState);    
 
        setContentView(R.layout.timertask);   
        txtView = (TextView)findViewById(R.id.txttime);  
 
        Message message = handler.obtainMessage(1);     // Message  
        handler.sendMessageDelayed(message, 1000);  
    }    
 
    final Handler handler = new Handler(){  
 
        public void handleMessage(Message msg){         // handle message  
            switch (msg.what) {  
            case 1:  
                recLen--;  
                txtView.setText("" + recLen);  
 
                if(recLen > 0){  
                    Message message = handler.obtainMessage(1);  
                    handler.sendMessageDelayed(message, 1000);      // send message  
                }else{  
                    txtView.setVisibility(View.GONE);  
                }  
            }  
 
            super.handleMessage(msg);  
        }  
    };  
}  

public class timerTask extends Activity{  
    private int recLen = 0;  
    private TextView txtView;  
 
    public void onCreate(Bundle savedInstanceState){  
        super.onCreate(savedInstanceState);  
 
        setContentView(R.layout.timertask);  
        txtView = (TextView)findViewById(R.id.txttime);  
          
        new Thread(new MyThread()).start();         // start thread  
    }     
 
    final Handler handler = new Handler(){          // handle  
        public void handleMessage(Message msg){  
            switch (msg.what) {  
            case 1:  
                recLen++;  
                txtView.setText("" + recLen);  
            }  
            super.handleMessage(msg);  
        }  
    };  
 
    public class MyThread implements Runnable{      // thread  
        @Override  
        public void run(){  
            while(true){  
                try{  
                    Thread.sleep(1000);     // sleep 1000ms  
                    Message message = new Message();  
                    message.what = 1;  
                    handler.sendMessage(message);  
                }catch (Exception e) {  
                }  
   

Handler与Runnable（最简单型）  

public class timerTask extends Activity{  
    private int recLen = 0;  
    private TextView txtView;  
 
    public void onCreate(Bundle savedInstanceState){  
        super.onCreate(savedInstanceState);  
 
        setContentView(R.layout.timertask);  
        txtView = (TextView)findViewById(R.id.txttime);  
        runnable.run(); 
    }     
 
    Handler handler = new Handler();  
    Runnable runnable = new Runnable() {  
        @Override  
        public void run() {  
            recLen++;  
            txtView.setText("" + recLen);  
            handler.postDelayed(this, 1000);  
        }  
    };  
}  

方法5，综合了前几种方法的优点，是最简的