Android存儲訪問框架：我應該使用哪個路徑來保存文件？

我通過下面的代碼通過SAF獲得我的可移動SD卡的權限。通過點擊浮動操作按鈕「文件」我授予我的應用程序的權限。之後，我想用FAB「文件夾」創建一個文件。Android存儲訪問框架：我應該使用哪個路徑來保存文件？

當我嘗試將文件保存到uri路徑時，它說該路徑不存在。我必須使用哪條路徑？（字符串[]僅用於測試不同的路徑的路徑...）

FAB-文件

FloatingActionButton fab_new_file = (FloatingActionButton) rLayoutFrgEmpresas.findViewById(R.id.fab_menu_item_file); 
fab_new_file.setOnClickListener(new View.OnClickListener() { 

    @Override 
    public void onClick(View view) { 
     System.out.print("FAB File clicked"); 
     Intent intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE); 
     intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true); 
     intent.putExtra(Intent.EXTRA_LOCAL_ONLY, true); 
     intent.addFlags(Intent.FLAG_GRANT_PERSISTABLE_URI_PERMISSION); 
     intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION); 
     intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION); 
     startActivityForResult(intent, 42); 
    } 
}); 
mainPath = this.getArguments().getString("mainpath"); 
getFilesFromDir(mainPath, mainPath); 
return rLayoutFrgEmpresas;

onActivityActionResult

@Override 
    public void onActivityResult(int requestCode, int resultCode, Intent data){ 
     System.out.print("onActivityResult started"); 
     if (resultCode == Activity.RESULT_OK) { 
      if (data != null) { 
       treeUri = data.getData(); 

       System.out.print("treeUri: "+treeUri); 
       if (requestCode == 42){ 

        int takeFlags = data.getFlags(); 
        takeFlags &= (Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION); 

        getContext().getContentResolver().takePersistableUriPermission(treeUri, takeFlags); 
        System.out.print("Permissions: "+getContext().getContentResolver().getPersistedUriPermissions()); 

        editor = getActivity().getSharedPreferences("spicysoftware.com.phonemanager", MODE_PRIVATE).edit(); 
        editor.putString("treeUri", treeUri.toString()); 
        if(editor.commit()){ 
         System.out.print("treeUri sharedPref added"); 
        } 
       } 
      } 
     } 
     super.onActivityResult(requestCode, resultCode, data); 
    }

FAB-文件夾

FloatingActionButton fab_new_folder = (FloatingActionButton) rLayoutFrgEmpresas.findViewById(R.id.fab_menu_item_folder); 
fab_new_folder.setOnClickListener(new View.OnClickListener() { 
    @Override 
    public void onClick(View view) { 
     Log.i("Information: ", "FAB Folder clicked"); 

     String str_treeUri = prefs.getString("treeUri", null); 
     Uri myUri = Uri.parse(str_treeUri); 

     Log.i("Information: ", "myUri from shared Pref: "+myUri); 

     String[] path = { 
       ""+myUri, 
       ""+myUri+"/", 
       "/com.android.externalstorage.documents/tree/B9BE-18A6/", 
       "/tree/B9BE-18A6/", 
       "/storage/B9BE-18A6/" 
     }; 

     for(int i=0; i<path.length; i++) { 
      File testfile = new File("" + path[i] + "testfile" + System.currentTimeMillis() + ".txt"); 
      if (!testfile.exists()) { 
       Log.i("Information: ", testfile+ " does not exist"); 
       try { 
        testfile.createNewFile(); 
        getFilesFromDir(textView_currentPath.getText() + "", textView_currentPath.getText() + ""); 
        Log.i("File " + testfile, "has been created!"); 
       } catch (IOException e) { 
        e.printStackTrace(); 
       } 
      } 
     } 
    } 
});

logcat的

*Before clicked FAB-File* 
04-12 16:41:26.748 2197-2197/spicysoftware.com.phonemanager D/[email protected][MainActivity]: ViewPostImeInputStage processPointer 0 
04-12 16:41:26.821 2197-2197/spicysoftware.com.phonemanager D/[email protected][MainActivity]: ViewPostImeInputStage processPointer 1 
04-12 16:41:26.833 2197-2197/spicysoftware.com.phonemanager I/Information:: FAB File clicked 
04-12 16:41:26.868 2197-2197/spicysoftware.com.phonemanager D/[email protected][MainActivity]: MSG_WINDOW_FOCUS_CHANGED 0 
04-12 16:41:27.036 2197-2197/spicysoftware.com.phonemanager D/InputTransport: Input channel destroyed: fd=73 
04-12 16:41:34.131 2197-2197/spicysoftware.com.phonemanager I/Information:: onActivityResult started 
04-12 16:41:34.140 2197-2197/spicysoftware.com.phonemanager I/Information:: Permissions: [UriPermission {uri=content://com.android.externalstorage.documents/tree/B9BE-18A6%3A, modeFlags=3, persistedTime=1492008094137}] 
04-12 16:41:34.151 2197-2197/spicysoftware.com.phonemanager I/Information:: treeUri sharedPref added 
04-12 16:41:34.173 2197-2285/spicysoftware.com.phonemanager D/mali_winsys: EGLint new_window_surface(egl_winsys_display*, void*, EGLSurface, EGLConfig, egl_winsys_surface**, egl_color_buffer_format*, EGLBoolean) returns 0x3000, [1080x1920]-format:1 
*After clicked FAB-File* 

    *Before clicked FAB-Folder* 
04-12 17:04:36.011 25159-25159/spicysoftware.com.phonemanager D/[email protected][MainActivity]: ViewPostImeInputStage processPointer 0 
04-12 17:04:36.084 25159-25159/spicysoftware.com.phonemanager D/[email protected][MainActivity]: ViewPostImeInputStage processPointer 1 
04-12 17:04:36.093 25159-25159/spicysoftware.com.phonemanager I/Information:: FAB Folder clicked 
04-12 17:04:36.093 25159-25159/spicysoftware.com.phonemanager I/Information:: myUri from shared Pref: content://com.android.externalstorage.documents/tree/B9BE-18A6%3A 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager I/Information:: content:/com.android.externalstorage.documents/tree/B9BE-18A6%3Atestfile1492009476094.txt does not exist 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err: java.io.IOException: No such file or directory 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively0(Native Method) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:280) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.File.createNewFile(File.java:948) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at spicysoftware.com.phonemanager.StorageFragment$1.onClick(StorageFragment.java:172) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View.performClick(View.java:6207) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View$PerformClick.run(View.java:23639) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.handleCallback(Handler.java:751) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.dispatchMessage(Handler.java:95) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Looper.loop(Looper.java:154) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.app.ActivityThread.main(ActivityThread.java:6688) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.lang.reflect.Method.invoke(Native Method) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468) 
04-12 17:04:36.094 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager I/Information:: content:/com.android.externalstorage.documents/tree/B9BE-18A6%3A/testfile1492009476095.txt does not exist 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err: java.io.IOException: No such file or directory 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively0(Native Method) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:280) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.File.createNewFile(File.java:948) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at spicysoftware.com.phonemanager.StorageFragment$1.onClick(StorageFragment.java:172) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View.performClick(View.java:6207) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View$PerformClick.run(View.java:23639) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.handleCallback(Handler.java:751) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.dispatchMessage(Handler.java:95) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Looper.loop(Looper.java:154) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.app.ActivityThread.main(ActivityThread.java:6688) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.lang.reflect.Method.invoke(Native Method) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358) 
04-12 17:04:36.095 25159-25159/spicysoftware.com.phonemanager I/Information:: /com.android.externalstorage.documents/tree/B9BE-18A6/testfile1492009476095.txt does not exist 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err: java.io.IOException: No such file or directory 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively0(Native Method) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:280) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.File.createNewFile(File.java:948) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at spicysoftware.com.phonemanager.StorageFragment$1.onClick(StorageFragment.java:172) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View.performClick(View.java:6207) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View$PerformClick.run(View.java:23639) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.handleCallback(Handler.java:751) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.dispatchMessage(Handler.java:95) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Looper.loop(Looper.java:154) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.app.ActivityThread.main(ActivityThread.java:6688) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.lang.reflect.Method.invoke(Native Method) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358) 
04-12 17:04:36.096 25159-25159/spicysoftware.com.phonemanager I/Information:: /tree/B9BE-18A6/testfile1492009476096.txt does not exist 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err: java.io.IOException: No such file or directory 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively0(Native Method) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:280) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.File.createNewFile(File.java:948) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at spicysoftware.com.phonemanager.StorageFragment$1.onClick(StorageFragment.java:172) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View.performClick(View.java:6207) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View$PerformClick.run(View.java:23639) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.handleCallback(Handler.java:751) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.dispatchMessage(Handler.java:95) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Looper.loop(Looper.java:154) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.app.ActivityThread.main(ActivityThread.java:6688) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.lang.reflect.Method.invoke(Native Method) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358) 
04-12 17:04:36.097 25159-25159/spicysoftware.com.phonemanager I/Information:: /storage/B9BE-18A6/testfile1492009476097.txt does not exist 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err: java.io.IOException: Permission denied 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively0(Native Method) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:280) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.io.File.createNewFile(File.java:948) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at spicysoftware.com.phonemanager.StorageFragment$1.onClick(StorageFragment.java:172) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View.performClick(View.java:6207) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.view.View$PerformClick.run(View.java:23639) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.handleCallback(Handler.java:751) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Handler.dispatchMessage(Handler.java:95) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.os.Looper.loop(Looper.java:154) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at android.app.ActivityThread.main(ActivityThread.java:6688) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at java.lang.reflect.Method.invoke(Native Method) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468) 
04-12 17:04:36.098 25159-25159/spicysoftware.com.phonemanager W/System.err:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358) 
04-12 17:04:48.021 25159-25159/spicysoftware.com.phonemanager D/[email protected][MainActivity]: ViewPostImeInputStage processKey 0 
04-12 17:04:48.046 25159-25159/spicysoftware.com.phonemanager D/[email protected][MainActivity]: ViewPostImeInputStage processKey 1 
    *After clicked FAB-Folder*

來源

2017-04-12 MSeiz5

我通過SAF獲得許可到我的可移動SD卡，代碼如下

不，你不知道。您可以訪問文檔樹。文檔樹所在的位置由用戶決定。它可能位於外部存儲設備，可移動存儲設備，Google Drive或其他用戶擁有DocumentProvider的地方。

之後，我想用FAB「文件夾」創建一個文件。

您可以使用DocumentFile和fromTreeUri()包裹，你從ACTION_OPEN_DOCUMENT_TREE回來了Uri。然後，使用它創建子樹，並獲取指向這些樹中的內容的值。然後，使用ContentResolver和openOutputStream()與Uri獲得OutputStream，您可以在其中編寫內容。

我必須使用哪條路徑？

無。 A Uri不是一個文件。

來源

2017-04-12 15:15:04 CommonsWare

是否有某處可以閱讀的教程？這些變化非常複雜...... – MSeiz5

Android存儲訪問框架：我應該使用哪個路徑來保存文件？

回答

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