android项目实现带进度条的系统通知栏消息

我们在做Android开发的时候经常会遇到后台线程执行的比如说下载文件的时候,这个时候我们希望让客户能看到后台有操作进行，这时候我们就可以使用进度条,那么既然在后台运行,为的就是尽量不占用当前操作空间，用户可能还要进行其他操作,最好的方法就是在通知栏有个通知消息并且有个进度条。本文给一个例子工读者参考.
效果图如下：

主界面只有一个按钮就不上文件了

通知栏显示所用到的布局文件content_view.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="fill_parent"
  android:layout_height="fill_parent"
  android:background="#00000000"
  android:orientation="vertical"
  android:padding="5dp"> 

  <ImageView
    android:id="@+id/content_view_image"
    android:layout_width="25dp"
    android:layout_height="25dp"
    android:src="@drawable/logo" 

    />
  <TextView
    android:id="@+id/content_view_text1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="0%"
    android:textColor="#000000"
    android:layout_toRightOf="@id/content_view_image"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="5dp"
    android:layout_marginLeft="15dp"
   />
  <ProgressBar
    android:id="@+id/content_view_progress"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    style="@android:style/Widget.ProgressBar.Horizontal"
    android:max="100"
    android:layout_below="@id/content_view_image"
    android:layout_marginTop="4dp"
    /> 

</RelativeLayout>

主运行类：

package yyy.testandroid4; 

import java.util.Timer;
import java.util.TimerTask; 

import android.app.Activity;
import android.app.AlertDialog.Builder;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager.NameNotFoundException;
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.RemoteViews;
import android.widget.Toast; 

public class TestAndroid4Activity extends Activity { 

  private Handler handler = new Handler(){
    @Override
    public void handleMessage(Message msg) {
      // TODO Auto-generated method stub
      super.handleMessage(msg);
      switch (msg.what) {
      case 0:
        notif.contentView.setTextViewText(R.id.content_view_text1, len+"%");
        notif.contentView.setProgressBar(R.id.content_view_progress, 100, len, false);
        manager.notify(0, notif); 

        break;
      case 1:
        Toast.makeText(TestAndroid4Activity.this, "下载完成", 0).show();
        break;
      default:
        break;
      }
    } 

  }; 

  private Button update,cancel;
  private int localVersion,serverVersion;
  private int len;
  private NotificationManager manager;
  private Notification notif;
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main); 

    update = (Button) findViewById(R.id.update); 

    update.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View arg0) {
        // TODO Auto-generated method stub
        //点击通知栏后打开的activity
        Intent intent = new Intent(TestAndroid4Activity.this,OtherActivity.class); 

        PendingIntent pIntent = PendingIntent.getActivity(TestAndroid4Activity.this, 0, intent, 0);
           manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        notif = new Notification();
        notif.icon = R.drawable.logo;
        notif.tickerText = "新通知";
        //通知栏显示所用到的布局文件
        notif.contentView = new RemoteViews(getPackageName(), R.layout.content_view);
        notif.contentIntent = pIntent;
        manager.notify(0, notif);
        new DownLoadThread().start();
      }
    }); 

  }
 } 

  private class DownLoadThread extends Thread{
    private Timer timer = new Timer();
    @Override
    public void run() {
      // TODO Auto-generated method stub
      super.run();
      timer.schedule(new TimerTask() {
        @Override
        public void run() {
          // TODO Auto-generated method stub 

          Message msg = new Message();
          msg.what = 0;
          msg.obj = len;
          handler.sendMessage(msg); 

          if(len == 100){
            timer.cancel();
            handler.sendEmptyMessage(1);
          } 

        }
      }, 0, 1000);
      len = 0;
      try {
        while(len < 100){
          len++;
          Thread.sleep(1000);
        }
      } catch (InterruptedException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
      }
    } 

  } 

}

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