ProgressBar

  还记得前面的ProgressDialog吗？在应用时，必须新建ProgressDialog对象，在运行时会弹出"对话框"作为提醒，此时应用程序的后台失去焦点，知道进程结束后，才能重新获取焦点，而在ProgressBar中，可以提示User后台程序正处于忙碌，也可以不让后台失去焦点。
  另外，系统默认的ProgressBar是小圆圈，你可以自己设置ProgressBar。如果你想要一个水平的进度条，你可以用android自带的样式。如下:

<ProgressBar android:id="@+id/progressBar1" 
             android:layout_width="fill_parent" 
             android:layout_height="wrap_content"
             android:visibility="gone"
             style="?android:attr/progressBarStyleHorizontal"/>

android:progressDrawable="@android:drawable/progress_horizontal"设置progressBar的mode（是圆圈还是长条等等）
           android:indeterminateDrawable="@android:drawable/progress_indeterminate_horizontal"设置progressBar.setIndeterminate(true)时的progressBar的背景进度Bar
  部分代码：

package com.kevin.processbar;

import android.R.integer;
import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;

public class Main extends Activity {
	private static final int STOP = 1;
	private static final int UPDATE = 2;
	private int count = 0;
	private TextView tv_title;
	private Button btn_progress;
	private ProgressBar progressBar;
	private Handler handler;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        tv_title = (TextView) findViewById(R.id.tv_title);
        progressBar = (ProgressBar) findViewById(R.id.progressBar1);
        progressBar.setIndeterminate(false);
        btn_progress = (Button) findViewById(R.id.button1);
        btn_progress.setOnClickListener(new ProgressButtonClickListener());
        handler = new Handler(){

			@Override
			public void handleMessage(Message msg) {
				switch (msg.what) {
				case UPDATE:
					if(!Thread.currentThread().isInterrupted()){
						/*
						 * 默认的ProgressBar（也就是转圈圈的那种），该方法对它没任何作用
						 * 另外如果你的进度条是一根长条，但是你设置了progressBar.setIndeterminate(true);
						 * 下面的方法同样没有作用
						 */
						progressBar.setProgress(count);
						System.out.println(progressBar.getProgress());
						tv_title.setText(getString(R.string.start) + "("
								+ String.valueOf(count) + "%" +
								")\n" + "Progress:" +
								String.valueOf(progressBar.getProgress()) +
								"\n" + "Indeterminate: " + Boolean.toString(progressBar.isIndeterminate()));
					}
					break;
				case STOP:
					tv_title.setText(R.string.finish);
					// 设置ProcessBar为隐藏
					progressBar.setVisibility(View.GONE);
					Thread.currentThread().isInterrupted();
					break;
				default:
					break;
				}
				super.handleMessage(msg);
			}        	
        };
    }
    class ProgressButtonClickListener implements OnClickListener{
		@Override
		public void onClick(View v) {
			tv_title.setText(R.string.start);
			// 将隐藏的ProgressBar显示出来
			progressBar.setVisibility(View.VISIBLE);
			// 指定ProgressBar最多为100
			progressBar.setMax(100);
			// 设置ProgressBar的初始值
			progressBar.setProgress(0);
			// 开启一个线程
			new Thread(new Runnable() {
				
				@Override
				public void run() {
					for(int i = 0 ; i < 10; i++){
						try{
							count = (i + 1) * 10;
							Thread.sleep(1000);
							if(i == 9){
								Message msg = new Message();
								msg.what = STOP;
								handler.sendMessage(msg);
								break;
							}else{
								Message msg = new Message();
								msg.what = UPDATE;
								handler.sendMessage(msg);
							}
						}catch (Exception e) {
							e.printStackTrace();
						}
					}
				}
			}).start();
		}	
    }
}