Android使用DocumentFile读写外置存储的问题

 import android.annotation.TargetApi; import android.content.Context; import android.content.SharedPreferences; import android.net.Uri; import android.os.Build; import android.os.ParcelFileDescriptor; import android.preference.PreferenceManager; import android.provider.DocumentsContract; import android.util.Log; import androidx.documentfile.provider.DocumentFile; import java.io.File; import java.io.FileDescriptor; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.RandomAccessFile; import java.util.ArrayList; import java.util.List; public class DocumentsUtils { private static final String TAG = DocumentsUtils.class.getSimpleName(); public static final int OPEN_DOCUMENT_TREE_CODE = 8000; private static List sExtSdCardPaths = new ArrayList<>(); private DocumentsUtils() { } public static void cleanCache() { sExtSdCardPaths.clear(); } /** * Get a list of external SD card paths. (Kitkat or higher.) * * @return A list of external SD card paths. */ @TargetApi(Build.VERSION_CODES.KITKAT) private static String[] getExtSdCardPaths(Context context) { if (sExtSdCardPaths.size() > 0) { return sExtSdCardPaths.toArray(new String[0]); } for (File file : context.getExternalFilesDirs("external")) { if (file != null && !file.equals(context.getExternalFilesDir("external"))) { int index = file.getAbsolutePath().lastIndexOf("/Android/data"); if (index <0) { Log.w(TAG, "Unexpected external file dir: " + file.getAbsolutePath()); } else { String path = file.getAbsolutePath().substring(0, index); try { path = new File(path).getCanonicalPath(); } catch (IOException e) { // Keep non-canonical path. } sExtSdCardPaths.add(path); } } } if (sExtSdCardPaths.isEmpty()) sExtSdCardPaths.add("/storage/sdcard1"); return sExtSdCardPaths.toArray(new String[0]); } /** * Determine the main folder of the external SD card containing the given file. * * @param file the file. * @return The main folder of the external SD card containing this file, if the file is on an SD * card. Otherwise, * null is returned. */ @TargetApi(Build.VERSION_CODES.KITKAT) private static String getExtSdCardFolder(final File file, Context context) { String[] extSdPaths = getExtSdCardPaths(context); try { for (int i = 0; i = Build.VERSION_CODES.N) {//不同一目录 Uri renameSrcUri = DocumentsContract.renameDocument(context.getContentResolver(),//先重命名 srcDoc.getUri(), dest.getName()); res = DocumentsContract.moveDocument(context.getContentResolver(),//再移动 renameSrcUri, srcDoc.getParentFile().getUri(), destDoc.getUri()) != null; } } catch (Exception e) { e.printStackTrace(); } } } return res; } public static InputStream getInputStream(Context context, File destFile) { InputStream in = null; try { if (!canWrite(destFile) && isOnExtSdCard(destFile, context)) { DocumentFile file = DocumentsUtils.getDocumentFile(destFile, false, context); if (file != null && file.canWrite()) { in = context.getContentResolver().openInputStream(file.getUri()); } } else { in = new FileInputStream(destFile); } } catch (FileNotFoundException e) { e.printStackTrace(); } return in; } public static OutputStream getOutputStream(Context context, File destFile) { OutputStream out = null; try { if (!canWrite(destFile) && isOnExtSdCard(destFile, context)) { DocumentFile file = DocumentsUtils.getDocumentFile(destFile, false, context); if (file != null && file.canWrite()) { out = context.getContentResolver().openOutputStream(file.getUri()); } } else { out = new FileOutputStream(destFile); } } catch (FileNotFoundException e) { e.printStackTrace(); } return out; } /** * 获取文件流 * @param context * @param destFile 目标文件 * @param mode May be "w", "wa", "rw", or "rwt". * @return */ public static OutputStream getOutputStream(Context context, File destFile, String mode) { OutputStream out = null; try { if (!canWrite(destFile) && isOnExtSdCard(destFile, context)) { DocumentFile file = DocumentsUtils.getDocumentFile(destFile, false, context); if (file != null && file.canWrite()) { out = context.getContentResolver().openOutputStream(file.getUri(), mode); } } else { out = new FileOutputStream(destFile, mode.equals("rw") || mode.equals("wa")); } } catch (FileNotFoundException e) { e.printStackTrace(); } return out; } public static FileDescriptor getFileDescriptor(Context context, File destFile) { FileDescriptor fd = null; try { if (/*!canWrite(destFile) && */isOnExtSdCard(destFile, context)) { DocumentFile file = DocumentsUtils.getDocumentFile(destFile, false, context); if (file != null && file.canWrite()) { ParcelFileDescriptor out = context.getContentResolver().openFileDescriptor(file.getUri(), "rw"); fd = out.getFileDescriptor(); } } else { RandomAccessFile file = null; try { file = new RandomAccessFile(destFile, "rws"); file.setLength(0); fd = file.getFD(); } catch (Exception e){ e.printStackTrace(); } finally { if (file != null) { try { file.close(); } catch (IOException e) { e.printStackTrace(); } } } } } catch (FileNotFoundException e) { e.printStackTrace(); } return fd; } public static boolean saveTreeUri(Context context, String rootPath, Uri uri) { DocumentFile file = DocumentFile.fromTreeUri(context, uri); if (file != null && file.canWrite()) { SharedPreferences perf = PreferenceManager.getDefaultSharedPreferences(context); perf.edit().putString(rootPath, uri.toString()).apply(); Log.e(TAG, "save uri" + rootPath); return true; } else { Log.e(TAG, "no write permission: " + rootPath); } return false; } /** * 返回true表示没有权限 * @param context * @param rootPath * @return */ public static boolean checkWritableRootPath(Context context, String rootPath) { File root = new File(rootPath); if (!root.canWrite()) { Log.e(TAG,"sd card can not write:" + rootPath + ",is on extsdcard:" + DocumentsUtils.isOnExtSdCard(root, context)); if (DocumentsUtils.isOnExtSdCard(root, context)) { DocumentFile documentFile = DocumentsUtils.getDocumentFile(root, true, context); if (documentFile != null) { Log.i(TAG, "get document file:" + documentFile.canWrite()); } return documentFile == null || !documentFile.canWrite(); } else { SharedPreferences perf = PreferenceManager.getDefaultSharedPreferences(context); String documentUri = perf.getString(rootPath, ""); Log.i(TAG,"lum_2 get perf documentUri:" + documentUri); if (documentUri == null || documentUri.isEmpty()) { return true; } else { DocumentFile file = DocumentFile.fromTreeUri(context, Uri.parse(documentUri)); if (file != null) Log.i(TAG,"lum get perf documentUri:" + file.canWrite()); return !(file != null && file.canWrite()); } } }else{ Log.e(TAG,"sd card can write..."); } return false; } }

 if (DocumentsUtils.checkWritableRootPath(this, StringUtils.STORAGE_PATH)) {   //检查sd卡路径是否有 权限 没有显示dialog showOpenDocumentTree(); } private void showOpenDocumentTree() { Log.e("showOpenDocumentTree", "start check sd card..."); Intent intent = null; if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N) { StorageManager sm = getSystemService(StorageManager.class); StorageVolume volume = sm.getStorageVolume(new File(StringUtils.STORAGE_PATH)); if (volume != null) { intent = volume.createAccessIntent(null); } } Log.e("showOpenDocumentTree", "intent=" + intent); if (intent == null) { intent = new Intent(Intent.ACTION_OPEN_DOCUMENT_TREE); } startActivityForResult(intent, DocumentsUtils.OPEN_DOCUMENT_TREE_CODE); } //................................ @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { switch (requestCode) { case DocumentsUtils.OPEN_DOCUMENT_TREE_CODE: if (data != null && data.getData() != null) { Uri uri = data.getData(); DocumentsUtils.saveTreeUri(this, StringUtils.STORAGE_PATH, uri); Log.i(TAG,"DocumentsUtils.OPEN_DOCUMENT_TREE_CODE ： "  + uri); } break; } super.onActivityResult(requestCode, resultCode, data); } 

 grantUriPermission(getPackageName(), uri, Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION); getContentResolver().takePersistableUriPermission(uri, Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);