android 多线程实例源码下载

【核心代码】

  package com.example.multithread_handler01;




import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.TextView;

public class MainActivity extends Activity {
	private TextView tv;
	private ProgressBar bar1,bar2;
	private int pvalue;
	private Handler handler;
	private Button btn;
	private ImageView iv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv=(TextView) findViewById(R.id.textView1);
        bar1=(ProgressBar) findViewById(R.id.progressBar1);
        bar2=(ProgressBar) findViewById(R.id.progressBar2);
        btn=(Button) findViewById(R.id.button1);
        iv=(ImageView) findViewById(R.id.imageView1);
     
    	/*新建Handler对象并重写handleMessage()方法，
    	 * 实现水平进度条的进度更新，并用textview组件tv显示下载完成进度
    	 */
        handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
        	// TODO Auto-generated method stub
        	bar1.setProgress(msg.arg1);
			tv.setText("正在下载中……(" msg.arg1 "%)");
			if(msg.arg2==1){
				tv.setText("下载完成！");
				bar1.setVisibility(View.GONE);
				bar2.setVisibility(View.GONE);
				btn.setVisibility(View.GONE);
               iv.setImageResource(R.drawable.picture);
			}
		
        }

        };
 		
 		btn.setOnClickListener(new OnClickListener() {			
			@Override
			public void onClick(View arg0) {
				// TODO Auto-generated method stub
				bar1.setProgress(0);
				tv.setVisibility(View.VISIBLE);
				bar1.setVisibility(View.VISIBLE);
				bar2.setVisibility(View.VISIBLE);				
				/*新建线程，并在其run()方法中实现将随机产生的进度值每100ms发送一条消息给UI线程，
				 * 用来更新水平进度条的当前进度值
				 */							
				new Thread(new Runnable() {					
					@Override
					public void run() {
						// TODO Auto-generated method stub					
                    pvalue=0;
                    while(true){
                    	pvalue =(int)(Math.random()*10);
                    	try{
                    		Thread.sleep(100);
                    	}catch (InterruptedException e) {
							// TODO: handle exception
                    		e.printStackTrace();
						}
                    	Message msg=new Message();
                    	if(pvalue<bar1.getMax()){
                    		msg.arg1=pvalue;
                    		msg.arg2=0;
                    		handler.sendMessage(msg);
                    	}else{
                    		msg.arg1=bar1.getMax();
                    		msg.arg2=1;
                    		handler.sendMessage(msg);
                    		break;
                    	}
                    }
						}
						
				}).start();   
			}
		});
    }


    @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;
    }
    
}