记录一下
如果Scheme类型是content，那么直接ContentResolver查询，但是会发现有些文件查不到，比如一个文件在微信的缓存路径下，我们就不能通过ContentResolver拿到他的data字段。那么怎么办呢？复制一份到自己目录下不就好了？代码如下：

if (ContentResolver.SCHEME_CONTENT.equalsIgnoreCase(uri.getScheme())) {
                ContentResolver contentResolver = BaseApplication.getInstance().getContentResolver();
                Cursor cursor = contentResolver.query(uri, null, null, null, null);
                if (cursor.moveToFirst()) {
                    int pathIndex = cursor.getColumnIndex(MediaStore.Images.Media.DATA);
                    int nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME);
                    if (pathIndex == -1) {
                        path = contentUriToPath(contentResolver, uri, nameIndex == -1 ? null : cursor.getString(nameIndex));//解析失败时，path转file会报错，会被外部catch抓住
                    } else {
                        //查找成功
                        path = cursor.getString(pathIndex);
                    }
                }
                cursor.close();
                if (path != null) {
                    return new File(path);
                }
}

private static String contentUriToPath(ContentResolver contentResolver, Uri uri, String displayName) {

        try {


            if (contentResolver == null) {
                return null;
            }

            if (uri == null) {
                return null;
            }
            InputStream inputStream = contentResolver.openInputStream(uri);

            if (inputStream == null) {
                return null;
            }

            if (TextUtils.isEmpty(displayName)) {
                displayName = System.currentTimeMillis() + "_share_file";
            }


            File cacheDir = BaseApplication.getInstance().getCacheDir();

            File file = new File(cacheDir, displayName);

            //将文件复制到自己缓存目录下
            boolean b = FileUtils.copyFileStream(inputStream, new FileOutputStream(file));

            return b ? file.getAbsolutePath() : null;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

如果Scheme类型是file类型，那么我们就要用ContentResolver查询INTERNAL_CONTENT_URI和EXTERNAL_CONTENT_URI查询文件下面是EXTERNAL_CONTENT_URI查询代码。

if (ContentResolver.SCHEME_FILE.equalsIgnoreCase(uri.getScheme())) { 
                path = uri.getEncodedPath();//防止乱码
                if (path != null) {
                    path = Uri.decode(path);
                    ContentResolver cr = BaseApplication.getInstance().getContentResolver();
                    StringBuffer buff = new StringBuffer();
                    buff.append("(").append(MediaStore.Images.ImageColumns.DATA).append("=").append("'" + path + "'").append(")");
                    Cursor cur = cr.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, new String[]{MediaStore.Images.ImageColumns._ID, MediaStore.Images.ImageColumns.DATA}, buff.toString(), null, null);
                    int dataIdx;
                    for (cur.moveToFirst(); !cur.isAfterLast(); cur.moveToNext()) {
                        dataIdx = cur.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
                        path = cur.getString(dataIdx);
                    }
                    cur.close();
                }
                if (path != null) {
                    return new File(path);
                }
            }