Android实现计时与倒计时的方法汇总

2019-12-12 02:44:49

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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