看mars的视频,学的一些代码:
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; @Override protected 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{ @Override public void onClick(View v) { myHandler.post(myThread); } } class EndListener implements OnClickListener{ @Override public void onClick(View v) { myHandler.removeCallbacks(myThread); System.out.println("stop"); } } //一个线程变量 Runnable myThread = new Runnable(){ @Override public void run() { System.out.println("thread-"+ Thread.currentThread().getName()+" run @ "+sdf.format(new Date())); myHandler.postDelayed(myThread, 3000); } }; @Override public 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; } }
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; @Override protected 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() { @Override public void onClick(View v) { pb.setVisibility(View.VISIBLE); progressBarHandler.post(updateThread); } }); end = (Button)findViewById(R.id.button_end); end.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { progressBarHandler.removeCallbacks(updateThread); } }); } //处理progressBar的Handler private Handler progressBarHandler = new Handler(){ @Override public 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; @Override public 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); } } }; @Override public 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。
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 { @Override protected 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); } @Override public 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")); }; }; @Override public 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; } }