android开发中调用系统自带的文件选择器遇到的一些问题

来源：互联网发布：c 图形编程编辑：程序博客网时间：2024/05/17 08:53

1.调用系统的文件浏览器然后进入文件管理器选择文本文件后，直接回到文件浏览器页面造成文本文件无法选择

开始时候使用的方法：

Intent intent = new Intent(Intent.ACTION_GET_CONTENT);intent.setType("*/*");intent.addCategory(Intent.CATEGORY_OPENABLE);startActivityForResult(intent, REQUEST_FILE);

解决办法：

Intent intent = new Intent(Intent.ACTION_GET_CONTENT);intent.setType("*/*");intent.addCategory(Intent.CATEGORY_OPENABLE);startActivityForResult(Intent.createChooser(intent, "Select a File to Upload"), REQUEST_FILE);

在startActivityForResult的时候对传入的intent参数做处理后就能够选择文本文件并返回路径了

2.调用系统的文件选择器后返回的是文件的Uri，这时需要我们自己转换为文件的path。转换方法如下（网上找的人家的代码）：

public class ConvertUriToFilePath {    /**     * Get a file path from a Uri. This will get the the path for Storage Access     * Framework Documents, as well as the _data field for the MediaStore and     * other file-based ContentProviders.     *     * @param context The context.     * @param uri     The Uri to query.     */    @RequiresApi(api = Build.VERSION_CODES.KITKAT)    public static String getPathFromURI(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];                }                 // TODO handle non-primary volumes            }            // 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 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());    }}

系统版本高于4.4的时候直接使用getPathFromUri()方法就可以直接得到文件的路径，低于4.4直接使用uri.getPath()获取路径。

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