Android实例，更新进度条，进度条应用。

效果如下：

activity_main.xml文件

<?xml version="1.0" encoding="utf-8"?>
<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:background="@mipmap/bj4"
    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="com.mingrisoft.startgame.MainActivity">

    <ProgressBar
        android:id="@+id/pg"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        style="@android:style/Widget.ProgressBar.Horizontal"
        android:max="100"
        android:layout_alignParentBottom="true"
        android:layout_marginBottom="50dp"/>

</RelativeLayout>

MainActivity.java文件

package com.mingrisoft.startgame;

import android.os.Message;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;
import android.widget.ProgressBar;

import android.os.Handler;
import android.widget.Toast;

import java.util.logging.LogRecord;

public class MainActivity extends ActionBarActivity {
    private ProgressBar progressBar;
    //当前进度
    private int mProgress=0;
    //消息处理
    private Handler mHandler;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //全屏显示
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        progressBar= (ProgressBar) findViewById(R.id.pg);
        //消息处理机制
        mHandler=new Handler() {
            @Override
            public void handleMessage(Message msg) {
                if(msg.what==0x111){
                    //更新进度条
                    progressBar.setProgress(mProgress);
                }
                else
                {
                    //显示更新完成，进度条不再显示。
                    Toast.makeText(MainActivity.this, "耗时操作已完成", Toast.LENGTH_SHORT).show();
                    progressBar.setVisibility(View.GONE);
                }
            }
        };
        //创建一个线程，模拟耗时操作，并发出消息
        new Thread(new Runnable() {
            @Override
            public void run() {
                while(true)
                {
                    mProgress=doWork();
                    Message m=new Message();
                    if(mProgress<100){
                        m.what=0x111;//耗时操作未完成，为自定义代码，一般以0x开头
                        mHandler.sendMessage(m);
                    }
                    else
                    {
                        m.what=0x110;//耗时操作已完成
                        mHandler.sendMessage(m);
                        break;
                    }
                }
            }
            private  int doWork()
            {
                mProgress+=Math.random()*10;
                try {
                    Thread.sleep(200);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                return mProgress;
            }
        }).start();//开始线程
    }
}

完成啦！