Android学习之ProgressDialog

进度条对话框ProgressDialog经常用于不能马上完成的操作，为了避免用户莫名其妙的等待，给用户一个提示。本例中我们演示了两种进度条：条形进度条和圆形进度条。

1 主Acitivity的布局

<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"
    tools:context=".MainActivity" >

    <Button
        android:id="@+id/progress_horizonal"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="水平进度条"
        android:textSize="20sp" />

    <Button
        android:id="@+id/progress_circle"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="圆形进度条"
        android:textSize="20sp" />

</LinearLayout>

2 MainActivity的编写

package com.example.progressdialog;

import java.util.Random;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity {

	private Button btn_horizonal = null;
	private Button btn_circle = null;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);

		inital();
		setBtnOnClickListener();
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.activity_main, menu);
		return true;
	}

	private void inital() {
		btn_horizonal = (Button) findViewById(R.id.progress_horizonal);
		btn_circle = (Button) findViewById(R.id.progress_circle);
	}

	private void setBtnOnClickListener() {

		btn_horizonal.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				showProgressDialog(ProgressDialog.STYLE_HORIZONTAL,
						"正在努力处理数据...", "请稍后...");
			}
		});

		btn_circle.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View v) {
				// TODO Auto-generated method stub
				showProgressDialog(ProgressDialog.STYLE_SPINNER, "正在努力删除...",
						"请稍后...");
			}
		});
	}
    
	/**进度条的最大值*/
	private static final int MAX_PROGRESS_VALUE = 100;
	private ProgressDialog progressDialog = null;
	private Handler progressHandler = null;
	/**记录当前进度的值*/
	private int progress = 0;
    /**
     * 显示进度对话框
     * @param style 进度框风格，长方形还是圆形
     * @param title 显示的title
     * @param message 显示的提示信息
     */
	private void showProgressDialog(int style, String title, String message) {
		// 创建ProgressDialog类的对象实体
		progressDialog = new ProgressDialog(this);
		progressDialog.setIcon(R.drawable.ic_launcher);
		//设置标题
		progressDialog.setTitle(title);
		//设置显示的提示信息
		progressDialog.setMessage(message);
		// 设置进度对话框的风格
		progressDialog.setProgressStyle(style);
		// 设置ProgressDialog不可以按退回按键取消 
        progressDialog.setCancelable(false); 
		// 设置进度对话框的进度最大值
		progressDialog.setMax(MAX_PROGRESS_VALUE);
		//设置暂停按钮
		progressDialog.setButton("暂停", new DialogInterface.OnClickListener() {

			@Override
			public void onClick(DialogInterface dialog, int which) {
				// TODO Auto-generated method stub
				// 删除消息队列中的消息来停止计时器
				progressHandler.removeMessages(1);
			}
		});
		//设置取消按钮
		progressDialog.setButton2("取消", new DialogInterface.OnClickListener() {

			@Override
			public void onClick(DialogInterface dialog, int which) {
				// TODO Auto-generated method stub
				// 删除消息队列中的消息来停止定时器
				progressHandler.removeMessages(1);
				progress = 0;
				progressDialog.setProgress(0);
				dismissProgressDialog();
			}
		});
		progressDialog.show();

		progressHandler = new Handler() {

			@Override
			public void handleMessage(Message msg) {
				// TODO Auto-generated method stub
				super.handleMessage(msg);
				if (progress >= MAX_PROGRESS_VALUE) {
					// 进度达到了最大值，关闭对话框
					progress = 0;
					dismissProgressDialog();
				} else {
					// 进度增一
					progress++;
					progressDialog.incrementProgressBy(1);
					// 第一个参数表示消息代码，第二个参数表示下一次调用handlerMessage要等待的毫秒数
					progressHandler.sendEmptyMessageDelayed(1,
							500 + new Random().nextInt(500));
				}
			}

		};
		// 设置进度条的初始值
		progress = (progress > 0) ? progress : 0;
		// 设置进度框中的进度值
		progressDialog.setProgress(progress);
		// 发送消息代码
		progressHandler.sendEmptyMessage(1);
	}
	
	/**
	 * 让进度对话框消失
	 */
	private void dismissProgressDialog(){
		progressDialog.dismiss();
	}
}

实际效果如下：