//檢查權限 public void checkPermission() {  if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {   ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);   //發現沒有權限，調用requestPermissions方法向用戶申請權限，requestPermissions接收三個參數，第一個是context，第二個是一個String數組，我們把要申請的權限   //名放在數組中即可，第三個是請求碼，只要是唯一值就行  } else {   openAlbum();//有權限就打開相冊  } } public void openAlbum() {  //通過intent打開相冊，使用startactivityForResult方法啟動actvity，會返回到onActivityResult方法，所以我們還得復寫onActivityResult方法  Intent intent = new Intent("android.intent.action.GET_CONTENT");  intent.setType("image/*");  startActivityForResult(intent, CHOOSE_PHOTO); } //彈出窗口向用戶申請權限 @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {  super.onRequestPermissionsResult(requestCode, permissions, grantResults);//彈出授權的窗口，這條語句也可以刪除，沒有影響  //獲得了用戶的授權結果，保存在grantResults中，判斷grantResult中的結果來決定接下來的操作  switch (requestCode) {   case 1:    if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {     openAlbum();    } else {     Toast.makeText(this, "授權失敗，無法操作", Toast.LENGTH_SHORT).show();    }    break;   default:    break;  } } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {  super.onActivityResult(requestCode, resultCode, data);  switch (requestCode) {   case CHOOSE_PHOTO:    if (resultCode == RESULT_OK) {     if (Build.VERSION.SDK_INT >= 19) {      handleImageOnkitKat(data);//高于4.4版本使用此方法處理圖片     } else {      handleImageBeforeKitKat(data);//低于4.4版本使用此方法處理圖片     }    }    break;   default:    break;  } } @TargetApi(19) private void handleImageOnkitKat(Intent data) {  String imagePath = null;  Uri uri = data.getData();  if (DocumentsContract.isDocumentUri(this, uri)) {   //如果是document類型的uri，則通過document id處理   String docId = DocumentsContract.getDocumentId(uri);   if ("com.android.providers.media.documents".equals(uri.getAuthority())) {    String id = docId.split(":")[1];//解析出數字格式的id    String selection = MediaStore.Images.Media._ID + "=" + id;    imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);   } else if ("com.android,providers.downloads.documents".equals(uri.getAuthority())) {    Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(docId));    imagePath = getImagePath(contentUri, null);   }  } else if ("content".equalsIgnoreCase(uri.getScheme())) {   imagePath = getImagePath(uri, null);  }  displayImage(imagePath); } private void handleImageBeforeKitKat(Intent data) {  Uri uri = data.getData();  String imagePath = getImagePath(uri, null);  displayImage(imagePath); } //獲得圖片路徑 public String getImagePath(Uri uri, String selection) {  String path = null;  Cursor cursor = getContentResolver().query(uri, null, selection, null, null); //內容提供器  if (cursor != null) {   if (cursor.moveToFirst()) {    path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA)); //獲取路徑   }  }  cursor.close();  return path; } //展示圖片 private void displayImage(String imagePath) {  if (imagePath != null) {   Bitmap bitImage = BitmapFactory.decodeFile(imagePath);//格式化圖片   mImage.setImageBitmap(bitImage);//為imageView設置圖片  } else {   Toast.makeText(MainActivity.this, "獲取圖片失敗", Toast.LENGTH_SHORT).show();  } }