Android(安卓)ProgressBar的使用!

大家好，今天给大家讲一下Android中ProgressBar的使用，这个控件在开发中还是经常用到的，比如用户浏览网页的时候，中间肯定有个传输过程，所以用进度条让用户耐心等待。再比如我在Android Market下载应用，它也会有进度条显示下载进度。我为什么要举这两个例子呢，是因为它们分别是圆形进度条和长形进度条的代表。如下面两张图：

为了让大家更容易理解我将简单写一个Demo，大家可以按照我的步骤一步一步来。

第一步：新建一个Android工程命名为ProgressBarDemo.

第二步:修改main.xml代码如下(圆形进度条和长形进度条这里样式不同用系统自带的):

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <TextView android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="Welcome to Mr Wei's blog" /> <ProgressBar android:id="@+id/rectangleProgressBar" style="?android:attr/progressBarStyleHorizontal" mce_style="?android:attr/progressBarStyleHorizontal" android:layout_width="fill_parent" android:layout_height="wrap_content" android:visibility="gone" /> <ProgressBar android:id="@+id/circleProgressBar" style="?android:attr/progressBarStyleLarge" mce_style="?android:attr/progressBarStyleLarge" android:layout_width="wrap_content" android:layout_height="wrap_content" android:visibility="gone" /> <Button android:id="@+id/button" android:text="Show ProgressBar" android:layout_width="wrap_content" android:layout_height="wrap_content" /> </LinearLayout>

第三步:修改ProgressBarDemo.java代码如下：

package com.tutor.progress;import android.app.Activity;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.view.View;import android.widget.Button;import android.widget.ProgressBar;public class ProgressBarDemo extends Activity { private ProgressBar rectangleProgressBar,circleProgressBar;private Button mButton;protected static final int STOP = 0x10000;protected static final int NEXT = 0x10001;private int iCount = 0; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); //findView By id rectangleProgressBar = (ProgressBar)findViewById(R.id.rectangleProgressBar); circleProgressBar = (ProgressBar)findViewById(R.id.circleProgressBar); mButton = (Button)findViewById(R.id.button); rectangleProgressBar.setIndeterminate(false); circleProgressBar.setIndeterminate(false); mButton.setOnClickListener(new Button.OnClickListener() {public void onClick(View v) {rectangleProgressBar.setVisibility(View.VISIBLE);circleProgressBar.setVisibility(View.VISIBLE);rectangleProgressBar.setMax(100);rectangleProgressBar.setProgress(0);circleProgressBar.setProgress(0);//创建一个线程,每秒步长为5增加,到100%时停止Thread mThread = new Thread(new Runnable() {public void run() {for(int i=0 ; i < 20; i++){try{iCount = (i + 1) * 5;Thread.sleep(1000);if(i == 19){Message msg = new Message();msg.what = STOP;mHandler.sendMessage(msg);break;}else{Message msg = new Message();msg.what = NEXT;mHandler.sendMessage(msg);}}catch (Exception e) {e.printStackTrace();}}}});mThread.start();}}); } //定义一个Handler private Handler mHandler = new Handler(){ public void handleMessage(Message msg){ switch (msg.what) {case STOP:rectangleProgressBar.setVisibility(View.GONE);circleProgressBar.setVisibility(View.GONE);Thread.currentThread().interrupt();break;case NEXT:if(!Thread.currentThread().isInterrupted()){rectangleProgressBar.setProgress(iCount);circleProgressBar.setProgress(iCount);}break;} } };}

第四步：运行上述工程，效果如下图:

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