android 根据文件Uri获取图片url

今天，简单讲讲android里如何通过文件的Uri获取文件的路径url。

昨天，我讲了如何调用手机的文件管理器获取文件资源，但是文件管理器返回的是文件的Uri，我们需要通过Uri获取文件的url才可以操作文件。昨天的博客虽然写了一种Uri转url的代码，但是我自己也没有很懂，于是在网上查找资料，最终解决了问题。这里记录一下。

一.简易版处理(实际并没发现有什么问题)

public static String getRealPathFromURI(Context context, Uri contentURI) {String result;Cursor cursor = context.getContentResolver().query(contentURI,new String[]{MediaStore.Images.ImageColumns.DATA},//null, null, null);if (cursor == null) result = contentURI.getPath();else {cursor.moveToFirst();int index = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);result = cursor.getString(index);cursor.close();}return result;}

简单讲讲，这种代码直接通过Uri使用contentProvider获取数据库的文件的url，网上说android 4.4后这种代码是有问题的，但是我没有测试，大家可以测试看看。

2.复杂版处理

public class GetPathFromUri { /** * 专为Android4.4设计的从Uri获取文件绝对路径 */public static String getPath(final Context context, final Uri uri) { final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT; // DocumentProvider if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) { // ExternalStorageProvider if (isExternalStorageDocument(uri)) { final String docId = DocumentsContract.getDocumentId(uri); final String[] split = docId.split(":"); final String type = split[0]; if ("primary".equalsIgnoreCase(type)) { return Environment.getExternalStorageDirectory() + "/" + split[1]; } } // DownloadsProvider else if (isDownloadsDocument(uri)) { final 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); } // MediaProvider else if (isMediaDocument(uri)) { final 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); } } // MediaStore (and general) else if ("content".equalsIgnoreCase(uri.getScheme())) { return getDataColumn(context, uri, null, null); } // File else if ("file".equalsIgnoreCase(uri.getScheme())) { return 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 uriThe 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()); } }

简单讲讲，这种代码对android4.4之前和之后做了分别的处理，在android 4.4后又根据url的类型，如ExternalStorageProvider，DownloadsProvider，MediaProvider分别进行处理。具体怎么处理，上面写的很清楚。这个代码比较全面，建议大家使用。

顺便讲讲url转Uri，这个绝对路径转Uri比较简单

以绝对路径创建一个File对象，然后调用

Uri.fromFile(file)

android 根据文件Uri获取图片url就讲完了。

就这么简单。