android多线程应用范例,实例讲解Android多线程应用开发中Handler的使用

其实可以理解Handler为主线程和另外的线程之间进行数据更新的东东，并且Handler在主线程中，并在Handler直接调用线程的run方法

package com.Handler02;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

public class Handler02Activity extends Activity {

/** Called when the activity is first created. */

private Handler handler=new Handler();

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

handler.post(thread1);

setContentView(R.layout.main);

System.out.println("================Main==============="+Thread.currentThread().getId());

System.out.println("============Main========="+Thread.currentThread().getName());

}

Runnable thread1=new Runnable() {

@Override

public void run() {

System.out.println("======thread1==============="+Thread.currentThread().getId());

System.out.println("========thread1============"+Thread.currentThread().getName());

try {

Thread.sleep(10000);

} catch (Exception e) {

// TODO: handle exception

}

}

};

}

结果是主线程等待10s后才显示出来，并且线程ID

package com.Handler4;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.view.View;

import android.widget.TextView;

public class Handler4Activity extends Activity {

/** Called when the activity is first created. */

private TextView textView;

private MyHandler myHandler=new MyHandler();

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

textView=(TextView)this.findViewById(R.id.textView1);

}

class MyHandler extends Handler{

//从消息队列中取出并handleMessage处理消息

@Override

public void handleMessage(Message msg) {

textView.setText((String)msg.obj);

}

}

public void download(View view){

Thread thread=new Thread(new Runnable() {

@Override

public void run() {

try {

String s="zhangzhao";

Thread.sleep(5000);

//数据发送出来

//textView.setText(s);

Message message=Message.obtain();//最好不要new，这个obtain会节省资源

message.obj=s;

myHandler.sendMessage(message);//没有指定looper那么就会发送给主线程中的looper

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

});

thread.start();//会出错原因是在非UI线程里面直接操作UI

//主线程维护了一个消息对列，当其他的线程有数据需要传递给主线程的时候，你就把数据封装成一个Message对象，然后放在主线程的

//消息队列中去，对应消息的处理由Looper，子线程通过Handler把下载完的数据封装到Message里面，然后把消息取出来交给Handler进行处理

//通过Handle和Message实现两个线程之间达到共享数据

}

}

package com.Handler5;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.view.View;

import android.widget.Button;

import android.widget.ProgressBar;

import android.widget.TextView;

public class Handler5Activity extends Activity {

/** Called when the activity is first created. */

private ProgressBar progressBar;

private Button button;

private TextView textView;

private MyHandler myHandler=new MyHandler();

int i=0;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

progressBar = (ProgressBar)this.findViewById(R.id.progressBar1);

textView=(TextView)this.findViewById(R.id.textView1);

}

class MyHandler extends Handler{

@Override

public void handleMessage(Message msg) {

int pos =(Integer)msg.obj;

progressBar.setProgress(pos);

textView.setText(pos+"%");

}

}

public void downLoad(View view){

new Thread(new Runnable() {

@Override

public void run() {

while(i<=100){

try {

Thread.sleep(300);

i+=10;

Message message=Message.obtain();

message.obj=i;

myHandler.sendMessage(message);

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

}

}).start();

}

}

效果：