setProgress方法不更新进度条，当我的文件被下载

Question

1. 代码下载文件：

   Dialog dialog; 
   int totalSize = 0; 
   ProgressBar mProgressBar; 
   int downloadedSize = 0; 
   
   public void downloadFile(){ 
       try { 
        URL url = new URL("http://.../my_file.mp3"); 
        HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection(); 
   
        urlConnection.setRequestMethod("GET"); 
        urlConnection.setDoOutput(true); 
   
        urlConnection.connect(); 
   
        File SDCardRoot = Environment.getExternalStorageDirectory(); 
   
        File dir = new File(SDCardRoot.getAbsolutePath(), "/dossier1/dossier2"; 
        dir.mkdirs(); 
   
        File file = new File(dir, "my_file.mp3"); 
   
        FileOutputStream fileOutput = new FileOutputStream(file); 
   
        InputStream inputStream = urlConnection.getInputStream(); 
   
        totalSize = urlConnection.getContentLength(); 
   
        runOnUiThread(new Runnable() { 
         public void run() { 
          mProgressBar.setMax(totalSize); 
         } 
        }); 
   
        byte[] buffer = new byte[1024]; 
        int bufferLength = 0; 
   
        while ((bufferLength = inputStream.read(buffer)) > 0) { 
         fileOutput.write(buffer, 0, bufferLength); 
         downloadedSize += bufferLength; 
   
         runOnUiThread(new Runnable() { 
          public void run() { 
           mProgressBar.setProgress(downloadedSize); 
          } 
         }); 
        } 
   
        fileOutput.close(); 
   
        runOnUiThread(new Runnable() { 
         public void run() { 
          //mProgressBar.dismiss(); 
         } 
        }); 
   
       } catch (final MalformedURLException e) { 
        showError("Error : MalformedURLException " + e); 
        e.printStackTrace(); 
       } catch (final IOException e) { 
        showError("Error : IOException " + e); 
        e.printStackTrace(); 
       } 
       catch (final Exception e) { 
        showError("Error : Please check your internet connection " + e); 
       } 
   } 
   

2. showProgress方法：

   public void showProgress(){ 
   dialog = new Dialog(context); 
   dialog.requestWindowFeature(Window.FEATURE_NO_TITLE); 
   dialog.setContentView(R.layout.myprogressdialog); 
   dialog.setTitle("Download Progress"); 
   
   TextView text = (TextView) dialog.findViewById(R.id.tv1); 
   text.setText("Downloading..."); 
   cur_val = (TextView) dialog.findViewById(R.id.cur_pg_tv); 
   cur_val.setText("Starting download..."); 
   dialog.show(); 
   
   mProgressBar = (ProgressBar)dialog.findViewById(R.id.progress_bar); 
   mProgressBar.setProgress(0); 
   mProgressBar.setProgressDrawable(context.getResources().getDrawable(R.drawable.blue_progress)); 
   } 
   

3. 布局为mProgressDialog（ myprogressdialog.xml中的res/layout）：

   <?xml version="1.0" encoding="utf-8"?> 
   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
   android:layout_width="match_parent" 
   android:layout_height="match_parent" 
   android:id="@+id/layout_root" 
   android:orientation="vertical" 
   android:padding="10dp"> 
   
   <TextView 
   android:id="@+id/tv1" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:textColor="#FFF" 
   android:text="hello" 
   android:textStyle="bold" 
   /> 
   
   <ProgressBar 
   android:id="@+id/progress_bar" 
   android:layout_width="match_parent" 
   android:layout_height="wrap_content" 
   android:progress="0" 
   android:layout_marginTop="5dp" 
   android:layout_marginBottom="10dp" 
   style="?android:attr/progressBarStyleHorizontal" 
   android:maxHeight="10dip" 
   android:minHeight="10dip" 
   /> 
   
   <TextView 
   android:id="@+id/cur_pg_tv" 
   android:layout_width="wrap_content" 
   android:layout_height="wrap_content" 
   android:textColor="#0F0" 
   android:text="hello" 
   android:layout_marginTop="5dp" 
   android:textStyle="bold|italic" /> 
   
   </LinearLayout> 
   

4. XML进行（在res blue_progress.xml /绘制）给人一种蓝色的mProgressBar

   <?xml version="1.0" encoding="utf-8"?> 
   <layer-list xmlns:android="http://schemas.android.com/apk/res/android"> 
   
   <item android:id="@android:id/background"> 
   <shape> 
       <corners android:radius="5dip" /> 
       <gradient android:startColor="#ff9d9e9d" 
        android:centerColor="#ff5a5d5a" 
        android:centerY="0.75" 
        android:endColor="#ff747674" 
        android:angle="270" 
        /> 
   </shape> 
   </item> 
   <item android:id="@android:id/progress"> 
   <clip> 
       <shape> 
        <corners android:radius="5dip" /> 
        <gradient android:startColor="@android:color/holo_blue_bright" 
         android:centerColor="@android:color/holo_blue_dark" 
         android:centerY="0.75" 
         android:endColor="@android:color/holo_blue_light" 
         android:angle="270" 
         /> 
       </shape> 
   </clip> 
   </item> 
   </layer-list> 
   

setProgress方法下载我的文件时不更新进度！ 你能告诉我任何解决方案吗？

Answer 1

https://developer.android.com/reference/android/os/AsyncTask.html

我建议你上的AsyncTask阅读了，因为里面还有一些非常好的工具，可以帮助你异步更新UI线程。
异步任务允许您在后台线程上运行任务，并在完成（或正在进行）时为UI提供更新。通常这可以让你跳过制作UI Runnable - 但这取决于你的情况。

无论如何， 您想重写的方法是在AsyncTask中的onProgressUpdate。此外，它可能会为您在未来尝试完成此项工作节省一些麻烦。

祝你好运！希望有所帮助。