Android中实现多线程的方法

第一种：继承Thread类,实现run()方法；调用父类Thread的start()方法,启动线程。

package com.example.android_thread;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.widget.TextView;


public class MainActivity extends Activity {
    TextView tv;
    MyHandler myHandler;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView)findViewById(R.id.tv);
        new MyThread("thread1").start();
        new MyThread("thread2").start();
         myHandler = new MyHandler();
    }

    class MyThread extends Thread{
        String name;
        public MyThread(String t1){
            name=t1;
        }
        public void run(){
                Message msg=new Message();
                Bundle b=new Bundle();
                b.putString("text", name);
                msg.setData(b);
                myHandler.sendMessage(msg);
        }
    }
    
    class MyHandler extends Handler{
        public MyHandler(){   
        }
        public void handleMessage(Message msg){
            super.handleMessage(msg);
            Bundle b=msg.getData();
            String str=b.getString("text");
            tv.setText(str);
            Log.i("xxx",str);
        }
    }

}

第二种：继承Runnable接口,实现run()方法；把对象传递给Thread的带Runnable参数的构造函数,然后调用Thread的start()方法,启动线程。---------------->一般使用这种方式实现多线程

继承Thread类的缺点是,由于java不支持多重继承,因此只能单一继承

但是实现Runnable接口就不一样了。可以实现多个接口。

 

package com.example.android_thread;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.widget.TextView;


public class MainActivity extends Activity {
    TextView tv;
    MyHandler myHandler;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv = (TextView)findViewById(R.id.tv);
        myHandler = new MyHandler();
        //区别1，这里也可以修改一下
        new Thread(new MyThread("thread1")).start();
        new Thread(new MyThread("thread2")).start();
    
    }
    //区别2,这里可以修改一下，
    class MyThread implements Runnable{
        String name;
        public MyThread(String t1){
            name=t1;
        }
        public void run(){
                Message msg=new Message();
                Bundle b=new Bundle();
                b.putString("text", name);
                msg.setData(b);
                myHandler.sendMessage(msg);
        }
    }
    
    class MyHandler extends Handler{
        public MyHandler(){   
        }
        public void handleMessage(Message msg){
            super.handleMessage(msg);
            Bundle b=msg.getData();
            String str=b.getString("text");
            tv.setText(str);
            Log.i("xxx",str);
        }
    }

}

 更简练的一种写法：

在Runnable或者Thread的构造函数中实现线程的启动，实现的主要代码
可以修改为：

new Thread("thread1")
 new Thread("thread2")

 

 class MyThread implements Runnable{
        String name;
        Thread thread;
        public MyThread(String t1){
            name=t1;
            thread(this).start()
        }
        public void run(){
                Message msg=new Message();
                Bundle b=new Bundle();
                b.putString("text", name);
                msg.setData(b);
                myHandler.sendMessage(msg);
        }
    }