Handler 简单用法
package com.example.handletest;import java.text.SimpleDateFormat;import java.util.Date;import android.os.Bundle;import android.os.Handler;import android.app.Activity;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;/** * 简单的例子： * 包含： * 1.一个handler * 2.一个线程 * 两个button通过handler控制：线程进入handler的线程队列 * 线程进入handler队列后会自动调用run方法运行 * @author hongyehwy */public class MainActivity extends Activity {private static final SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");private Button starButton;private Button endButton;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);starButton = (Button)findViewById(R.id.button_satrt);starButton.setOnClickListener(new StartListener());endButton = (Button)findViewById(R.id.button_end);endButton.setOnClickListener(new EndListener());}private Handler myHandler = new Handler();class StartListener implements OnClickListener{@Overridepublic void onClick(View v) {myHandler.post(myThread);}}class EndListener implements OnClickListener{@Overridepublic void onClick(View v) {myHandler.removeCallbacks(myThread);System.out.println("stop");}}//一个线程变量Runnable myThread = new Runnable(){@Overridepublic void run() {System.out.println("thread-"+ Thread.currentThread().getName()+" run @ "+sdf.format(new Date()));myHandler.postDelayed(myThread, 3000);}};@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}}
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demo2：
package com.example.handleandprogressbar;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.ProgressBar;/** * * @author hongyehwy * 部件 * 1.两个button，分别控制进度条的前进、停止前进 * 2.进度条 * 执行过程： * 1.button 通过 handler控制线程的启动，线程启动后增加progressbar的进度,并将增加后的值传递到数据队列 * 2.handler重写handleMessage方法，从msg中获取当前progressbar的大小，调用progressbar的方法更新progressbar * 3.当progressbar的大小 > 100的时候，从线程队列中删除线程 * */public class MainActivity extends Activity {private ProgressBar pb;private Button start;private Button end;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);pb = (ProgressBar)findViewById(R.id.progressBar);start = (Button)findViewById(R.id.button_start);start.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {pb.setVisibility(View.VISIBLE);progressBarHandler.post(updateThread);}});end = (Button)findViewById(R.id.button_end);end.setOnClickListener(new OnClickListener() {@Overridepublic void onClick(View v) {progressBarHandler.removeCallbacks(updateThread);}});}//处理progressBar的Handlerprivate Handler progressBarHandler = new Handler(){@Overridepublic void handleMessage(Message msg) {super.handleMessage(msg);pb.setProgress(msg.arg1);progressBarHandler.post(updateThread);};};//处理progressBar的线程private Runnable updateThread = new Runnable() {int i = 0;@Overridepublic void run() {System.out.println("start updateThread ");if( i < 100){i = i + 10;Message msg = progressBarHandler.obtainMessage();msg.arg1 = i;try{Thread.sleep(1000);}catch (Exception e) {}progressBarHandler.sendMessage(msg);}else{progressBarHandler.removeCallbacks(this);}}};@Overridepublic boolean onCreateOptionsMenu(Menu menu) {getMenuInflater().inflate(R.menu.main, menu);return true;}}?
前面两个demo中，都是在主线程中操作handle对象，并不是实际意义上的异步线程操作。
下面的demo通过HandlerThread获取一个非主线程looper，然后在这个looper中处理这些异步操作。
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demo3
package com.example.handletest;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.HandlerThread;import android.os.Looper;import android.os.Message;import android.view.Menu;/** * 简单的例子： * 包含： * 1.一个HandlerThread * 2.一个继承自Handler的类，添加带looper参数的构造函数,重载handlerMessage方法 * 执行过程： * 1.通过HandlerThread获得一个非主线程的looper对象，并将这个looper对象分配给Handler对象。 * 2.获取Handler的msg，填充msg对象（发送异步线程消息消息），并在Handler对象的handleMessage方法中处理这个消息。 * * @author hongyehwy */public class MainActivity2 extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main2);System.out.println("activity thread id-->"+Thread.currentThread().getId());System.out.println("activity thread name-->"+Thread.currentThread().getName());HandlerThread hThread = new HandlerThread("Handler Thread");hThread.start();MyHandler myHandler = new MyHandler(hThread.getLooper());Message msg = myHandler.obtainMessage();Bundle bundle = new Bundle();bundle.putString("name", "kate");bundle.putString("age", "18");msg.setData(bundle);msg.sendToTarget();}class MyHandler extends Handler{public MyHandler() {}public MyHandler(Looper looper) {super(looper);}@Overridepublic void handleMessage(Message msg) {System.out.println("MyHandler thread id-->"+Thread.currentThread().getId());System.out.println("MyHandler thread name-->"+Thread.currentThread().getName());Bundle bundle = msg.getData();System.out.println("name = "+bundle.getString("name")+" ; age = "+bundle.getString("age"));};};@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.getMenuInflater().inflate(R.menu.main, menu);return true;}}?