從Android的sd卡讀取xml文件不起作用

我試圖從URL下載一個xml文件，將它保存到內部sd卡並解析xml。這是我的下載功能：從Android的sd卡讀取xml文件不起作用

private static String Name = project_name.getText().toString(); 
private static String URL = url.getText().toString(); 

//Download XML file from URL 
DownloadManager.Request request = new DownloadManager.Request(Uri.parse(URL)); 
request.setTitle("Download von "+Name+".xml"); 
request.setDestinationInExternalPublicDir("/", Name+".xml"); 
// get download service and enqueue file 
DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE); 
manager.enqueue(request); 
private static ArrayList<Datapoint> itemsList = parseXML();

這是解析器功能：

private ArrayList<Datapoint> parseXML() { 

     try { 

      Log.w("AndroidParseXMLActivity", "Start"); 
      /** Handling XML */ 
      SAXParserFactory spf = SAXParserFactory.newInstance(); 
      SAXParser sp = spf.newSAXParser(); 
      XMLReader xr = sp.getXMLReader(); 
      File file = new File(Environment.getExternalStorageDirectory()+"/"+ Name+ ".xml"); 

      XMLContentHandler myXMLHandler = new XMLContentHandler(); 
      xr.setContentHandler(myXMLHandler); 

      xr.parse(new InputSource(new InputStreamReader(new FileInputStream(file)))); 

      itemsList = myXMLHandler.getItemsList(); 

      Log.w("AndroidParseXMLActivity", "Done"); 
     } 
     catch (Exception e) { 
      Log.w("AndroidParseXMLActivity",e); 
     } 
     return itemsList ; 
    }

但我得到以下logcat的錯誤：

09-28 09:30:36.500: W/AndroidParseXMLActivity(7881): Start 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): java.io.FileNotFoundException: /mnt/sdcard/mich.xml: open failed: ENOENT (No such file or directory) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at libcore.io.IoBridge.open(IoBridge.java:406) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at java.io.FileInputStream.<init>(FileInputStream.java:78) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at de.myapp.CreateProject.parseXML(CreateProject.java:348) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at de.myapp.CreateProject.save_project(CreateProject.java:298) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at de.myapp.CreateProject.onOptionsItemSelected(CreateProject.java:115) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at android.app.Activity.onMenuItemSelected(Activity.java:2564) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:984) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at com.android.internal.view.menu.ActionMenuView.invokeItem(ActionMenuView.java:613) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at com.android.internal.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:121) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at android.view.View.performClick(View.java:3644) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at android.view.View$PerformClick.run(View.java:14313) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at android.os.Handler.handleCallback(Handler.java:605) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at android.os.Handler.dispatchMessage(Handler.java:92) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at android.os.Looper.loop(Looper.java:137) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at android.app.ActivityThread.main(ActivityThread.java:4517) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at java.lang.reflect.Method.invokeNative(Native Method) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at java.lang.reflect.Method.invoke(Method.java:511) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at dalvik.system.NativeStart.main(Native Method) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): Caused by: libcore.io.ErrnoException: open failed: ENOENT (No such file or directory) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at libcore.io.Posix.open(Native Method) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): at libcore.io.IoBridge.open(IoBridge.java:390) 
09-28 09:30:36.540: W/AndroidParseXMLActivity(7881): ... 22 more 
09-28 09:30:36.590: E/SKIA(7881): FimgApiStretch:stretch failed 
09-28 09:30:39.350: D/AbsListView(7881): Get MotionRecognitionManager 
09-28 09:30:39.435: D/dalvikvm(7881): GC_CONCURRENT freed 238K, 5% free 15465K/16135K, paused 1ms+4ms 
09-28 09:30:39.440: D/AbsListView(7881): [unregisterDoubleTapMotionListener] 
09-28 09:30:39.440: I/MotionRecognitionManager(7881): .unregisterListener :/listener count = 0->0, [email protected] 
09-28 09:30:40.675: D/FILESTREAM(7881): Filepath:/data/data/de.myapp/files/mich 
09-28 09:30:40.675: D/AndroidRuntime(7881): Shutting down VM 
09-28 09:30:40.675: W/dalvikvm(7881): threadid=1: thread exiting with uncaught exception (group=0x40c621f8) 
09-28 09:30:40.680: E/AndroidRuntime(7881): FATAL EXCEPTION: main 
09-28 09:30:40.680: E/AndroidRuntime(7881): java.lang.RuntimeException: Unable to start activity ComponentInfo{de.myapp/myapp.ProjectView}: java.lang.NullPointerException 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1970) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1995) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.app.ActivityThread.access$600(ActivityThread.java:128) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1161) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.os.Handler.dispatchMessage(Handler.java:99) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.os.Looper.loop(Looper.java:137) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.app.ActivityThread.main(ActivityThread.java:4517) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at java.lang.reflect.Method.invokeNative(Native Method) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at java.lang.reflect.Method.invoke(Method.java:511) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at dalvik.system.NativeStart.main(Native Method) 
09-28 09:30:40.680: E/AndroidRuntime(7881): Caused by: java.lang.NullPointerException 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at de.myapp.ProjectView.setup(ProjectView.java:148) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at de.myapp.ProjectView.onCreate(ProjectView.java:62) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.app.Activity.performCreate(Activity.java:4533) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1053) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1934) 
09-28 09:30:40.680: E/AndroidRuntime(7881):  ... 11 more

我也曾在設置此權限我AndroidManifest.xml

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" > 
</uses-permission>

xml被下載並保存到SD卡，因爲我可以看到並使用Windows資源管理器打開它。

任何想法？

來源

2012-09-28 Mr.Mojo

需要讀取SD卡內容READ_EXTERNAL_STORAGE許可。 –

我已經添加了這個權限（這聽起來很合邏輯;-)），但仍然有錯誤：java.io.FileNotFoundException：/mnt/sdcard/aberjetzt.xml：打開失敗：ENOENT（沒有這樣的文件或目錄）' –

它工作了一段時間，但現在相同的錯誤。我沒有改變任何代碼來下載和解析。我需要另一個特殊功能從SD卡上讀取嗎？ –

嘗試使用此代碼，公共無效DownloadFromUrl（字符串DownloadUrl，字符串文件名）{

嘗試{ 文件根= android.os.Environment.getExternalStorageDirectory（）;

 File dir = new File (root.getAbsolutePath() + "/xmls"); 
     if(dir.exists()==false) { 
      dir.mkdirs(); 
     } 

     URL url = new URL(DownloadUrl); //you can write here any link 
     File file = new File(dir, fileName); 

     long startTime = System.currentTimeMillis(); 
     Log.d("DownloadManager", "download begining"); 
     Log.d("DownloadManager", "download url:" + url); 
     Log.d("DownloadManager", "downloaded file name:" + fileName); 

     /* Open a connection to that URL. */ 
     URLConnection ucon = url.openConnection(); 

     /* 
     * Define InputStreams to read from the URLConnection. 
     */ 
     InputStream is = ucon.getInputStream(); 
     BufferedInputStream bis = new BufferedInputStream(is); 

     /* 
     * Read bytes to the Buffer until there is nothing more to read(-1). 
     */ 
     ByteArrayBuffer baf = new ByteArrayBuffer(5000); 
     int current = 0; 
     while ((current = bis.read()) != -1) { 
      baf.append((byte) current); 
     } 


     /* Convert the Bytes read to a String. */ 
     FileOutputStream fos = new FileOutputStream(file); 
     fos.write(baf.toByteArray()); 
     fos.flush(); 
     fos.close(); 
     Log.d("DownloadManager", "download ready in" + ((System.currentTimeMillis() - startTime)/1000) + " sec");

}趕上（IOException的發送）{ Log.d（「下載管理」，「錯誤：」 + e）條; }

}

來源

2012-09-28 08:48:58

這是針對來自url的downlaod xml文件。您可以根據您的要求進行修改。 –

我的xml文件的下載工作正常，唯一的問題是xml解析器無法打開sdcard上的donwloaded文件 –

使用File myFile = new File（「/ sdcard/yourXmlFIle.xml」）; –

從Android的sd卡讀取xml文件不起作用

回答

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