Android UI控件之ProgressBar进度条

<LinearLayout 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:orientation="vertical">    <TextView     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="简单进度条的展示"      android:layout_gravity="center_horizontal"/>    <ProgressBar     android:id="@+id/progressBar1"     android:layout_width="wrap_content"     android:layout_height="wrap_content"      android:layout_gravity="center_horizontal"     />    <ProgressBar     android:id="@+id/progressBar2"     style="?android:attr/progressBarStyleLarge"     android:layout_width="wrap_content"     android:layout_height="wrap_content"       android:layout_gravity="center_horizontal"/>    <ProgressBar     android:id="@+id/progressBar3"     style="?android:attr/progressBarStyleHorizontal"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:layout_gravity="center_horizontal"      android:max="100"     android:minWidth="180dip"     android:minHeight="40dip"     />  </LinearLayout> 

package com.kiritor.ui_progressbar;  import android.os.Bundle; import android.app.Activity; import android.view.Menu; import android.widget.ProgressBar;  public class MainActivity extends Activity implements Runnable {    private ProgressBar bar = null;   private Thread thread = null;// 声明一个线程   private boolean stateChange;    @Override   protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);     bar = (ProgressBar) findViewById(R.id.progressBar3);     thread = new Thread(this);     thread.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;   }    @Override   public void run() {     while (true) {       int current = bar.getProgress();// 得到当前进度值       int currentMax = bar.getMax();// 得到进度条的最大进度值       //int secCurrent = bar.getSecondaryProgress();// 得到底层当前进度值       // 以下代码实现进度值越来越大，越来越小的一个动态效果       if (stateChange == false) {         if (current >= currentMax) {           stateChange = true;         } else {           // 设置进度值           bar.setProgress(current + 1);           // 设置底层进度值           bar.setSecondaryProgress(current + 1);         }       } else {         if (current <= 0) {           stateChange = false;         } else {           bar.setProgress(current - 1);           bar.setSecondaryProgress(current - 1);         }       }       try {         Thread.sleep(50);       } catch (InterruptedException e) {         // TODO Auto-generated catch block         e.printStackTrace();       }     }    } }