Android 使用Service进行下载并在状态栏显示进度

版权声明：转载请标明出处 https://blog.csdn.net/panyongjie2577 https://blog.csdn.net/panyongjie2577/article/details/88363801

声明

这是一篇我之前我在2012年写的博客，里面有些东西是基于2012年时安卓的系统来进行编写的，现在写这篇博客的原因是想尽量恢复之前丢失的博客。此博客里面提及的技术还是能够使用的，只是需要在高版本的系统中进行兼容，如在android6.0上需要动态获取存储权限、android 8.0及以上系统版本对于下载apk自动提示安装需要做的特殊处理进行修改一下就可以了。

实现过程

android 自动检测版本在这里就不用说了，今天想和大家一起分享的是如何将下载更新文件最小化到任务栏下载，替代掉丑陋的对话框提示下载，对话框提示下载的用户体验相当不好，我们把它修改成为后台下载这样可以改善用户的使用体验。

下载进度布局xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:background="#f2f2f2" >
    <LinearLayout 
       android:layout_width="fill_parent"
       android:layout_height="wrap_content"
       android:orientation="horizontal"
       android:gravity="center">
       <ImageView 
           android:id="@+update_id/ivLogo"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:src="@drawable/logo"
           android:layout_margin="10dip" />
       <LinearLayout 
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:orientation="vertical"
           android:layout_weight="1"
           android:layout_marginRight="10dip">
           <TextView 
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               android:textColor="@color/deepblack"
               android:text="@string/app_name"
               android:textSize="18dip"
               android:textStyle="bold"/>
           <ProgressBar 
               android:id="@+update_id/pbDownload"
               android:layout_width="fill_parent"
               android:layout_height="12dip"
               android:progress="0"
               android:max="100"
               android:progressDrawable="@drawable/pb_style"
               style="?android:attr/progressBarStyleHorizontal" 
               mce_style="?android:attr/progressBarStyleHorizontal"   />
           <TextView 
               android:id="@+update_id/tvProcess"
               android:layout_width="wrap_content"
               android:layout_height="wrap_content"
               android:textColor="@color/deepblack"
               android:text="已下载0%"
               android:textSize="12dip"
              android:textStyle="bold" />
      </LinearLayout>
   </LinearLayout>
 </LinearLayout>

创建下载任务Service

public class UpdateService extends Service{
       private NotificationManager nm;
       private Notification notification;
       private File tempFile=null;
       private boolean cancelUpdate=false;
       private MyHandler myHandler;
       private int download_precent=0;
       private RemoteViews views; 
       private int notificationId=1234;

       @Override
       public IBinder onBind(Intent intent) {
              return null;
        }

       @Override
       public void onStart(Intent intent,int startId){
             super.onStart(intent, startId);
       }

       @Override
       public int onStartCommand(Intent intent,int flags,int startId){
             nm=(NotificationManager)getSystemService(NOTIFICATION_SERVICE);
             notification=new Notification();
             notification.icon=android.R.drawable.stat_sys_download;
            //notification.icon=android.R.drawable.stat_sys_download_done;
            notification.tickerText=getString(R.string.app_name)+"更新";
            notification.when=System.currentTimeMillis();
            notification.defaults=Notification.DEFAULT_LIGHTS;

            //设置任务栏中下载进程显示的views
            views=new RemoteViews(getPackageName(),R.layout.update);
            notification.contentView=views;

            PendingIntent contentIntent=PendingIntent.getActivity(this,0,new Intent(this,City.class),0);
            notification.setLatestEventInfo(this,"","", contentIntent);

            //将下载任务添加到任务栏中
            nm.notify(notificationId,notification);

            myHandler=new MyHandler(Looper.myLooper(),this);

            //初始化下载任务内容views
            Message message=myHandler.obtainMessage(3,0);
            myHandler.sendMessage(message);

            //启动线程开始执行下载任务
            downFile(intent.getStringExtra("url"));
            return super.onStartCommand(intent, flags, startId);
     }

    @Override
    public void onDestroy(){
       super.onDestroy();
    }

   //下载更新文件
   private void downFile(final String url) {
      new Thread() {
            public void run(){
                try {     
                      HttpClient client = new DefaultHttpClient();     
                     // params[0]代表连接的url     
                    HttpGet get = new HttpGet(url);        
                    HttpResponse response = client.execute(get);     
                    HttpEntity entity = response.getEntity();     
                    long length = entity.getContentLength();     
                    InputStream is = entity.getContent();
                    if (is != null) {
                           File rootFile=new File(Environment.getExternalStorageDirectory(), "/pinke");
                           if(!rootFile.exists()&&!rootFile.isDirectory())
                                rootFile.mkdir();
               
                           tempFile = new File(Environment.getExternalStorageDirectory(),

                                                                     "/pinke/"+url.substring(url.lastIndexOf("/")+1));
                          if(tempFile.exists())
                                tempFile.delete();
                          tempFile.createNewFile();
                  
                          //已读出流作为参数创建一个带有缓冲的输出流
                          BufferedInputStream bis = new BufferedInputStream(is);
          
                          //创建一个新的写入流，讲读取到的图像数据写入到文件中
                          FileOutputStream fos = new FileOutputStream(tempFile);
                          //已写入流作为参数创建一个带有缓冲的写入流
                          BufferedOutputStream bos = new BufferedOutputStream(fos);  
                     
                           int read; 
                           long count=0;
                           int precent=0;
                           byte[] buffer=new byte[1024];
                           while( (read = bis.read(buffer)) != -1 && !cancelUpdate){  
                               bos.write(buffer,0,read);
                               count+=read;
                               precent=(int)(((double)count/length)*100);

                               //每下载完成5%就通知任务栏进行修改下载进度
                               if(precent-download_precent>=5){
                                   download_precent=precent;
                                   Message message=myHandler.obtainMessage(3,precent);
                                   myHandler.sendMessage(message);    
                              }
                        }   
                        bos.flush();
                       bos.close();
                       fos.flush();
                       fos.close();
                       is.close();
                       bis.close(); 
                  }     
              
                  if(!cancelUpdate){
                      Message message=myHandler.obtainMessage(2,tempFile);
                     myHandler.sendMessage(message); 
                 }else{
                     tempFile.delete();
                }
            } catch (ClientProtocolException e) {  
                   Message message=myHandler.obtainMessage(4,"下载更新文件失败");
                   myHandler.sendMessage(message); 
            } catch (IOException e) {
                  Message message=myHandler.obtainMessage(4,"下载更新文件失败");
                  myHandler.sendMessage(message); 
            } catch(Exception e){
                  Message message=myHandler.obtainMessage(4,"下载更新文件失败");
                  myHandler.sendMessage(message); 
            }
        }
    }.start();       
}

//安装下载后的apk文件
private void Instanll(File file,Context context){
     Intent intent = new Intent(Intent.ACTION_VIEW);   
     intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
     intent.setAction(android.content.Intent.ACTION_VIEW);
     intent.setDataAndType(Uri.fromFile(file),"application/vnd.android.package-archive");    
     context.startActivity(intent);     
}   

/*事件处理类*/
class MyHandler extends Handler{
       private Context context;
       public MyHandler(Looper looper,Context c){
           super(looper);
          this.context=c;
       }

      @Override
      public void handleMessage(Message msg){
                super.handleMessage(msg);
               if(msg!=null){
                     switch(msg.what){
                           case 0:
                                   Toast.makeText(context,msg.obj.toString(), Toast.LENGTH_SHORT).show();
                                   break;
                           case 1:
                                  break;
                           case 2:
                                   //下载完成后清除所有下载信息，执行安装提示
                                  download_precent=0;
                                  nm.cancel(notificationId);
                                  Instanll((File)msg.obj,context);

                                  //停止掉当前的服务
                                  stopSelf();
                                  break;
                          case 3:

                                //更新状态栏上的下载进度信息
                                views.setTextViewText(R.update_id.tvProcess,"已下载"+download_precent+"%");
                                views.setProgressBar(R.update_id.pbDownload,100,download_precent,false);
                                notification.contentView=views;
                                nm.notify(notificationId,notification);
                                break;
                        case 4:
                              nm.cancel(notificationId);
                          break;
                      }
                  }
            }
     }
   }

在外面需要调用下载任务的地方使用startService(intent)来调用这个Service就可以了，最终的效果图片