67

我正在开发一些应用程序，它允许从 SD 卡中选择图像，将其保存到数据库中并为 ImageView 设置此值。我需要知道将 uri 转换为字符串和将字符串转换为 uri 的方法。现在我使用了 Uri 的 getEncodedPath() 方法，但是，例如，这段代码不起作用：

ImageView iv=(ImageView)findViewById(R.id.imageView1);
Uri uri=Uri.parse("/external/images/media/470939");
Log.e("uri1", uri.toString());
iv.setImageURI(uri);

因此我不知道如何将 Uri 保存到数据库中并从保存的值创建一个新的 Uri。请帮我解决它。

4

5 回答 5

115

我需要知道将 uri 转换为字符串和将字符串转换为 uri 的方法。

用于toString()将 a 转换Uri为String. 用于Uri.parse()将 a 转换String为Uri.

此代码不起作用

这不是 a 的有效字符串表示形式Uri。AUri有方案，"/external/images/media/470939"没有方案。

于 2013-05-01T18:59:36.903 回答
21

试试这个将字符串转换为uri

String mystring="Hello"
Uri myUri = Uri.parse(mystring);

Uri 转字符串

Uri uri;
String uri_to_string;
uri_to_string= uri.toString();
于 2017-09-29T05:46:45.623 回答
1

这将从 MediaProvider、DownloadsProvider 和 ExternalStorageProvider 获取文件路径，同时回退到您提到的非官方 ContentProvider 方法。

   /**
 * 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.
 * @author paulburke
 */
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];
            }

            // 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());
}
于 2016-10-04T11:08:38.083 回答
1

我不确定你是否解决了这个问题。跟进“CommonsWare”的评论。

这不是 Uri 的有效字符串表示形式。Uri 有一个方案，而“/external/images/media/470939”没有方案。

改变

Uri uri=Uri.parse("/external/images/media/470939");

到

Uri uri=Uri.parse("content://external/images/media/470939");

就我而言

Uri uri = Uri.parse("content://media/external/images/media/6562");
于 2018-12-10T13:02:50.410 回答
-2

您可以使用 Drawable 代替 Uri。

   ImageView iv=(ImageView)findViewById(R.id.imageView1);
   String pathName = "/external/images/media/470939"; 
   Drawable image = Drawable.createFromPath(pathName);
   iv.setImageDrawable(image);

这会奏效。

于 2013-05-01T19:03:17.193 回答