Android 4.4以上获取图片URI格式不同导致getContentResolver返回null

本文转自：http://www.jianshu.com/p/ae25718a1f05

Android 4.4以上获取图片URI格式不同导致getContentResolver返回null

今天在实现用户头像选择裁剪功能时，虚拟机裁剪没问题，实机却调用不了系统的裁剪，百度了一下以为是网上说的miui的裁剪的图片过大，或对return data分配的资源不够，可是我这连裁剪Activity都没有启动，所以可能性不大，试着Log输出一下，果然是因为getContentResolver()没有获得数据，这种情况大多都是Android系统版本问题，所以我又试着打印了uri的字符串，果然不同版本通过
intent.setAction(Intent.ACTION_PICK); intent.setData(MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
返回的uri格式不同
Android4.4以前获取的uri的字符串是“content://media/external/image/media”格式的，而4.4以后变成"file:///sdcard/mysong.mp3"格式，会导致
Cursor c = getContentResolver().query(uri,MediaStore.Images.Media.DATA, null, null, null);
获取的c里面并没有图片信息。而裁剪图片所需要获取图片的真实路径path可以使用由android_Y网友提供的根据Uri获取图片绝对路径，解决Android4.4以上版本Uri转换

     * 根据Uri获取图片绝对路径，解决Android4.4以上版本Uri转换     * @param activity     * @param imageUri     * @author yaoxing     * @date 2014-10-12     */    @TargetApi(19)    public static String getImageAbsolutePath(Activity context, Uri imageUri) {        if (context == null || imageUri == null)            return null;        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT &&Uri(context, imageUri)) {            if (isExternalStorageDocument(imageUri)) {                String docId = DocumentsContract.getDocumentId(imageUri);                String[] split = docId.split(":");                String type = split[0];                if ("primary".equalsIgnoreCase(type)) {                    return Environment.getExternalStorageDirectory() + "/" + split[1];                }            } else if (isDownloadsDocument(imageUri)) {                String id = DocumentsContract.getDocumentId(imageUri);                Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));                return getDataColumn(context, contentUri, null, null);            } else if (isMediaDocument(imageUri)) {                String docId = DocumentsContract.getDocumentId(imageUri);                String[] split = docId.split(":");                String type = split[0];                Uri contentUri = null;                if ("image".equals(type)) {                    contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;                } else if ("video".equals(type)) {                    contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;                } else if ("audio".equals(type)) {                    contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;                }                String selection = MediaStore.Images.Media._ID + "=?";                String[] selectionArgs = new String[] { split[1] };                return getDataColumn(context, contentUri, selection, selectionArgs);            }        } // MediaStore (and general)        else if ("content".equalsIgnoreCase(imageUri.getScheme())) {            // Return the remote address            if (isGooglePhotosUri(imageUri))                return imageUri.getLastPathSegment();            return getDataColumn(context, imageUri, null, null);        }        // File        else if ("file".equalsIgnoreCase(imageUri.getScheme())) {            return imageUri.getPath();        }        return null;    }    public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {        Cursor cursor = null;        String column = MediaStore.Images.Media.DATA;        String[] projection = { column };        try {            cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);            if (cursor != null && cursor.moveToFirst()) {                int index = cursor.getColumnIndexOrThrow(column);                return cursor.getString(index);            }        } finally {            if (cursor != null)                cursor.close();        }        return null;    }    /**     * @param uri The Uri to check.     * @return Whether the Uri authority is ExternalStorageProvider.     */    public static boolean isExternalStorageDocument(Uri uri) {        return "com.android.externalstorage.documents".equals(uri.getAuthority());    }    /**     * @param uri The Uri to check.     * @return Whether the Uri authority is DownloadsProvider.     */    public static boolean isDownloadsDocument(Uri uri) {        return "com.android.providers.downloads.documents".equals(uri.getAuthority());    }    /**     * @param uri The Uri to check.     * @return Whether the Uri authority is MediaProvider.     */    public static boolean isMediaDocument(Uri uri) {        return "com.android.providers.media.documents".equals(uri.getAuthority());    }    /**     * @param uri The Uri to check.     * @return Whether the Uri authority is Google Photos.     */    public static boolean isGooglePhotosUri(Uri uri) {        return "com.google.android.apps.photos.content".equals(uri.getAuthority());    }