Android（在外部SD卡上寫入）：java.io.IOException：權限被拒絕

Question

當我要在外部SD卡（名為/ storage / B9BE-18A6）上創建文件時，出現“權限被拒絕”錯誤。

我知道自Android M以來，您必須以編程方式請求寫入權限。因此，我從Arpit Patel（ Android 6.0 Marshmallow。無法寫入SD卡 ）插入了解決方案

我不知道為什么我仍然沒有這樣做的權限。 你們還有其他解決方案，可以在SD卡上創建文件嗎？

用於創建文件的代碼

    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) {

            int permission = ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.WRITE_EXTERNAL_STORAGE);
            if (permission != PackageManager.PERMISSION_GRANTED) {
                Log.v("Permission: " ,"Denied");

                if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(),
                        Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
                    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
                    builder.setMessage("Permission to access the SD-CARD is required")
                            .setTitle("Permission required");

                    builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {

                        public void onClick(DialogInterface dialog, int id) {
                            Log.i(TAG, "Clicked");
                            makeRequest();
                        }
                    });

                    AlertDialog dialog = builder.create();
                    dialog.show();

                } else {
                    makeRequest();
                }
            }else{
                Log.v("Permission: " ,"Granted");
                File file = new File(textView_currentPath.getText() + "/" + "testfile.txt");
                Log.v("filepatch: ", ""+file);
                if (!file.exists()) {
                    Log.v("Does "+file+" exists?", "No");
                    try {
                        file.createNewFile();
                        getFilesFromDir(textView_currentPath.getText() + "", textView_currentPath.getText() + "");
                        Log.v("File "+file,"has been created!");
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    });

LogCat

04-11 16:31:40.709 23404-23404/spicysoftware.com.phonemanager D/ViewRootImpl@ab22b33[MainActivity]: ViewPostImeInputStage processPointer 0
04-11 16:31:40.773 23404-23404/spicysoftware.com.phonemanager D/ViewRootImpl@ab22b33[MainActivity]: ViewPostImeInputStage processPointer 1
04-11 16:31:40.783 23404-23404/spicysoftware.com.phonemanager V/Permission:: Granted
04-11 16:31:40.783 23404-23404/spicysoftware.com.phonemanager V/filepatch:: /storage/B9BE-18A6/testfile.txt
04-11 16:31:40.783 23404-23404/spicysoftware.com.phonemanager V/Does /storage/B9BE-18A6/testfile.txt exists?: No
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err: java.io.IOException: Permission denied
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at java.io.UnixFileSystem.createFileExclusively0(Native Method)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:280)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at java.io.File.createNewFile(File.java:948)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at spicysoftware.com.phonemanager.StorageFragment$2.onClick(StorageFragment.java:187)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at android.view.View.performClick(View.java:6207)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at android.view.View$PerformClick.run(View.java:23639)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at android.os.Handler.handleCallback(Handler.java:751)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at android.os.Looper.loop(Looper.java:154)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:6688)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1468)
04-11 16:31:40.784 23404-23404/spicysoftware.com.phonemanager W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1358)

解決方案感謝@greenapps帶給我正確的方法。 解決方案在https://developer.android.com/guide/topics/providers/document-provider.html上有很好的記錄

        Intent intent = new Intent(Intent.ACTION_CREATE_DOCUMENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);

        String mimeType = "text/plain";
        String filename = "file"+System.currentTimeMillis() + ".txt";
        intent.setType(mimeType);
        intent.putExtra(Intent.EXTRA_TITLE, filename);
        startActivityForResult(intent, CREATE_REQUEST_CODE);

Answer 1

SD卡是只讀的。 所以你不會寫。 您只能寫入SD卡上特定於應用程序的目錄。 在你的情況下

/storage/B9BE-18A6/Android/data/spicysoftware.com.phonemanager

如果要在整個SD卡上寫入，則File類和FileOutputStream將不起作用。 然后，您必須使用Storage Access Framework。