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