Android实现计时与倒计时的常用方法小结

2020-04-11 11:20:32

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本文实例总结了Android实现计时与倒计时的常用方法。分享给大家供大家参考，具体如下：

方法一

Timer与TimerTask（Java实现）

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);           }         }       });     }   }; }

方法二

TimerTask与Handler（不用Timer的改进型）

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);     }   }; }

方法三

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);     }   }; }

方法四

Handler与Thread（不占用UI线程）

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) {         }       }     }   } }

方法五

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);     handler.postDelayed(runnable, 1000);   }     Handler handler = new Handler();   Runnable runnable = new Runnable() {     @Override     public void run() {       recLen++;       txtView.setText("" + recLen);       handler.postDelayed(this, 1000);     }   }; }

计时与倒计时

方法1，方法2和方法3，都是倒计时
方法4，方法5，都是计时
计时和倒计时，都可使用上述方法实现（代码稍加改动）

UI线程比较

方法1，方法2和方法3，都是在UI线程实现的计时；
方法4和方法5，是另开Runnable线程实现计时

实现方式比较

方法1，采用的是Java实现，即Timer和TimerTask方式；
其它四种方法，都采用了Handler消息处理

推荐使用

如果对UI线程交互要求不很高，可以选择方法2和方法3
如果考虑到UI线程阻塞，严重影响到用户体验，推荐使用方法4，另起线程单独用于计时和其它的逻辑处理
方法5，综合了前几种方法的优点，是最简的

希望本文所述对大家Android程序设计有所帮助。

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