[java] view plain copy 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）
[java] view plain copy 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
[java] view plain copy 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）
[java] view plain copy 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
[java] view plain copy 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
