android中怎么实现倒计时怎么按照小时分钟

Android实现计时与倒计时的五种方法：

方法一
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);
}
};
}
linux

方法二
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) {
}
}
}
}
}

方法三
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);
}
}
});
}
};
}
方法四
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