通过URI获取的文件路径为null的解决方法

今天调用系统自带的FileChooser后，根据Intent返回的uri获取路径的时一直返回null。

这个问题很奇怪，最后发现验证用的华为P7是Android 4.4系统。

先看下4.4之前的uri的形式：

Uri ： content://media/extenral/images/media/17766

是不是很熟悉？再看4.4及以后的Uri形式：

content://com.android.providers.media.documents/document/image%2706

    日志一打印出来我就明白是什么原因啦。这什么东西在Android 4.4前后不一样，4.4之前content后面是文件全路径，4.4之后不再直接表示路径啦。这就好办啦，翻了翻API后发现4.4以后的Uri还不唯一，并不是统一的一种格式，所以就来个通用解决办法好啦：

4.4以前通过Uri获取路径：data是Uri，filename是一个String的字符串，用来保存路径。

public static String getPathByUri(Context context, Uri data) {String filename=null;if (data.getScheme().toString().compareTo("content") == 0) {Cursor cursor = context.getContentResolver().query(data, new String[] { "_data" }, null, null, null);if (cursor.moveToFirst()) {filename = cursor.getString(0);}} else if (data.getScheme().toString().compareTo("file") == 0) {// file:///开头的urifilename = data.toString();filename = data.toString().replace("file://", "");// 替换file://if (!filename.startsWith("/mnt")) {// 加上"/mnt"头filename += "/mnt";}}return filename;}

    4.4以后根据Uri获取路径：

// 专为Android4.4设计的从Uri获取文件绝对路径，以前的方法已不好使@SuppressLint("NewApi")public static String getPathByUri4kitkat(final Context context, final Uri uri) {final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;// DocumentProviderif (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {if (isExternalStorageDocument(uri)) {// ExternalStorageProviderfinal String docId = DocumentsContract.getDocumentId(uri);final String[] split = docId.split(":");final String type = split[0];if ("primary".equalsIgnoreCase(type)) {return Environment.getExternalStorageDirectory() + "/" + split[1];}} else if (isDownloadsDocument(uri)) {// DownloadsProviderfinal String id = DocumentsContract.getDocumentId(uri);final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"),Long.valueOf(id));return getDataColumn(context, contentUri, null, null);} else if (isMediaDocument(uri)) {// MediaProviderfinal String docId = DocumentsContract.getDocumentId(uri);final String[] split = docId.split(":");final 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;}final String selection = "_id=?";final String[] selectionArgs = new String[] { split[1] };return getDataColumn(context, contentUri, selection, selectionArgs);}} else if ("content".equalsIgnoreCase(uri.getScheme())) {// MediaStore// (and// general)return getDataColumn(context, uri, null, null);} else if ("file".equalsIgnoreCase(uri.getScheme())) {// Filereturn uri.getPath();}return null;}/** * Get the value of the data column for this Uri. This is useful for * MediaStore Uris, and other file-based ContentProviders. *  * @param context *            The context. * @param uri *            The Uri to query. * @param selection *            (Optional) Filter used in the query. * @param selectionArgs *            (Optional) Selection arguments used in the query. * @return The value of the _data column, which is typically a file path. */public static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {Cursor cursor = null;final String column = "_data";final String[] projection = { column };try {cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);if (cursor != null && cursor.moveToFirst()) {final int column_index = cursor.getColumnIndexOrThrow(column);return cursor.getString(column_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());}

    安卓2.3.3 & 4.0.4 & 4.4 & 5.1.1 & 6.0真机亲测都正常，欢迎拷贝！

    最后，附上一个Video项目用到的相关函数供参考：

//return the id of URI    public static int getVideoUriByPath(Uri resultUri, Activity activity, String path){    resultUri= null;    int id=-1;    if(activity==null || path==null)    return id;    Uri preUri = Uri.parse("content://media/external/video/media/");     @SuppressWarnings("deprecation")Cursor cursor = activity.managedQuery(MediaStore.Video.Media.EXTERNAL_CONTENT_URI, null, null, null, MediaStore.Video.Media.DEFAULT_SORT_ORDER);        cursor.moveToFirst();        while (!cursor.isAfterLast()) {            String data = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA));            if (path.equals(data)) {                id = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID));                resultUri = Uri.withAppendedPath(preUri, "" + id);                break;            }            cursor.moveToNext();        }        return id;    }