模拟下载的进度条ProgressBar

作者：堕落的天使

图片效果

activity_main.xml(代码)

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <ProgressBar
        android:id="@+id/progressBar1"
        style="?android:attr/progressBarStyleHorizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_marginRight="68dp"
        android:layout_marginTop="32dp"
        android:layout_toLeftOf="@+id/textView1" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/progressBar1"
        android:layout_below="@+id/textView1"
        android:layout_marginLeft="15dp"
        android:layout_marginTop="22dp"
        android:text="开始下载" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/progressBar1"
        android:text="0%" />

</RelativeLayout>

MainActivity.java(代码)

package com.example.progresstest;

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.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;

public class MainActivity extends Activity {

    private TextView text;
    private Button button;

    private int max;
    private int progressStatus = 0;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final ProgressBar prog = (ProgressBar) findViewById(R.id.progressBar1);
        prog.setMax(100);
        max = prog.getMax();
        text = (TextView) findViewById(R.id.textView1);
        button = (Button) findViewById(R.id.button1);

        final Handler handler = new Handler(){
            @Override
            public void handleMessage(Message msg) {
                // TODO Auto-generated method stub
                super.handleMessage(msg);
                progressStatus = msg.what;
                prog.setProgress(progressStatus);
                text.setText(msg.what+"%");
            }
        };
        button.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                new Thread(new Runnable() {

                    @Override
                    public void run() {
                        for(int i=0; i <= max; i++){
                            Message msg = handler.obtainMessage();//重点
                            msg.what= i;
                            handler.sendMessage(msg);
                            try{
                                Thread.sleep(100);
                            }catch(Exception e){
                                e.printStackTrace();
                            }
                        }

                    }
                }).start();
            }
        });

    }

重点：1.handler的作用：

　　　2.Message：尽管Message的构造器是公开的，但是获取Message对象的最好方法是调用Message.obtain()或者Handler.obtainMessage(), 这样是从一个可回收对象池中获取Message对象。

推荐链接：http://www.cnblogs.com/wt616/archive/2011/06/21/2086162.html