本文是 Android 11 从外部存储读取文件到应用沙盒存储 的兄弟篇 :Android 11 从沙盒拷贝文件到外部共享存储区域,效果:
1. 需求中我们需要把自己应用沙盒的文件拷贝到外部共享存储区域,提供给其他app使用
1)外部共享存储区域:主要是指Enviromnent下的 如
Environment.DIRECTORY_DCIM
Environment.DIRECTORY_documentS
Environment.DIRECTORY_DOWNLOADS
Environment.DIRECTORY_MOVIES
Environment.DIRECTORY_PICTURES
Environment.DIRECTORY_MUSIC
等。
2)外部存储区域:指SDCard下任意路径。
在Android11以上已经不能随便访问任意外部存储路径了,并且也不能直接new File形式访问。(其实是在Android 10 谷歌就开始建议,但是没有强制。开发者可以通过在AndroidManifest.xml application节点中加上android:requestLegacyExternalStorage="true"属性还能继续访问外部存储)
2. 拷贝自己应用沙盒路径下文件到外部共享存储区域核心实现:
1)工具方法
public static boolean copySandFileToExternalUri(Context context, String filePath, Uri externalUri) { ContentResolver contentResolver = context.getContentResolver(); InputStream inputStream = null; OutputStream outputStream = null; boolean ret = false; try { outputStream = contentResolver.openOutputStream(externalUri); File sandFile = new File(filePath); if(sandFile.exists()) { inputStream = new FileInputStream(sandFile); int readCount = 0; byte[] buffer = new byte[1024]; while ((readCount = inputStream.read(buffer)) != -1) { outputStream.write(buffer, 0 , readCount); outputStream.flush(); } } ret = true; } catch (Exception e) { Log.e(TAG, "copy SandFile To ExternalUri. e = " + e.toString()); ret = false; } finally { try { if(outputStream != null) { outputStream.close(); } if(inputStream != null) { inputStream.close(); } Log.d(TAG, " input stream and output stream close successful."); } catch (Exception e) { e.printStackTrace(); Log.e(TAG, " input stream and output stream close fail. e = " + e.toString()); } return ret; } }
2) 调用例子
android 6.0以上需要动态申请权限,因此需要先进行权限判断:
已有权限走else case
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) { requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, FileHandlePresenter.PERMISSION_CODE_WRITE_EXTERNAL); } else { fileHandlePresenter.handleWriteExternalStorage(); }
权限申请回调
public void onRequestPermissionsResult(int requestCode, @NonNull @NotNull String[] permissions, @NonNull @NotNull int[] grantResults) { ...... } else if(requestCode == PERMISSION_CODE_WRITE_EXTERNAL) { if(grantResults[0] == PackageManager.PERMISSION_GRANTED) { handleWriteExternalStorage(); } } ...... }
获得权限后拷贝文件 *** 作:
public void handleWriteExternalStorage() { File sandFile = new File(mFragment.getActivity().getCacheDir() + File.separator + "test.txt"); if(!sandFile.exists()) { Toast.makeText(mFragment.getActivity(), "请先手动创建test.txt 并且保存到/data/data/包名/cache/下", Toast.LENGTH_LONG).show(); return; } ThreadManager.getInstence().postTask(new Runnable() { @Override public void run() { Uri externalUri = null; if(Build.VERSION.SDK_INT < Build.VERSION_CODES.Q) { File externalFile = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS); File destFile = new File(externalFile + File.separator + "test.txt"); externalUri = Uri.fromFile(destFile); } else { ContentResolver resolver = mFragment.getActivity().getContentResolver(); ContentValues values = new ContentValues(); values.put(MediaStore.Downloads.DISPLAY_NAME, "test.txt"); values.put(MediaStore.Downloads.RELATIVE_PATH, Environment.DIRECTORY_DOWNLOADS);//保存路径 Uri uri = MediaStore.Files.getContentUri("external"); externalUri = resolver.insert(uri, values); } boolean ret = FileHelper.copySandFileToExternalUri(mFragment.getActivity(), sandFile.getAbsolutePath(), externalUri); mFragment.getActivity().runonUiThread(new Runnable() { @Override public void run() { Toast.makeText(mFragment.getActivity(), "从沙盒" + sandFile.getAbsolutePath() + "中拷贝文件到外部存储" + Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath() + ", 结果= " + ret, Toast.LENGTH_LONG).show(); } }); } }); }
Demo地址:
CODING | 一站式软件研发管理平台
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