我将用户的图像uri保存为RoomDatabase中的字符串。 这就是我所知道的我不知道如何克服这个错误并显示将图像显示到RecyclerView中，我已经阅读了一些关于位图和etcetra的内容但是无法理解或使用它们进行编码。
RecyclerAdapter.java
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
Student current = students.get(position);
holder.nameItemView.setText(current.getName());
holder.numberItemView.setText(current.getNumber());
///here!
Uri uri = Uri.parse(current.getImagePath());
holder.studImage.setImageURI(uri);
}
它不显示图像。 我检查了调试器并看到了这个错误：
ava.lang.SecurityException: Permission Denial: opening provider com.android.providers.media.MediaDocumentsProvider from ProcessRecord{5ca0d63 20181:com.example.android.studmanagedbtrain/u0a92} (pid=20181, uid=10092) requires that you obtain access using ACTION_OPEN_DOCUMENT or related APIs
at android.os.Parcel.readException(Parcel.java:2004)
W/ImageView: Unable to open content: content:/com.android.providers.media.documents/document/image%3A42
java.io.FileNotFoundException: No content provider: content:/com.android.providers.media.documents/document/image%3A42
at android.content.ContentResolver.openTypedAssetFileDescriptor(ContentResolver.java:1396)
at android.content.ContentResolver.openAssetFileDescriptor(ContentResolver.java:1247)
at android.content.ContentResolver.openInputStream(ContentResolver.java:967)
at android.widget.ImageView.getDrawableFromUri(ImageView.java:951)
at android.widget.ImageView.resolveUri(ImageView.java:922)
at android.widget.ImageView.setImageURI(ImageView.java:531)
at .
etc.
etc.
.
at android.os.Handler.handleCallback(Handler.java:790)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6494)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
resolveUri failed on bad bitmap uri: content:/com.android.providers.media.documents/document/image%3A42
答案 0 :(得分：1)
使用Picasso库加载图片，如下所示：
Picasso.with(mContext).load(imageUrl).into(promotionImageView)
答案 1 :(得分：1)
您从文件中获取Uri的方式可能存在问题
Uri Uri = getUriFromFilePath(MainActivity.this, PhotoFilePath);
public Uri getUriFromFilePath(Context ctx, File filePath) {
Uri requirdUri = null;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
requirdUri = FileProvider.getUriForFile(ctx,
ctx.getApplicationContext().getPackageName() + PROVIDER_FILE_EXTENSION,
filePath);
} else {
requirdUri = Uri.fromFile(filePath);
}
return requirdUri;
}
在资源中创建路径文件 - ＆gt; XML RES / XML / paths.xml
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path
name="external_files"
path="." />
<root-path
name="external_files"
path="/storage/"/>
</paths>
在应用程序标记
中的manifest.xml文件中添加提供程序
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="com.demo.example.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/paths"/>
</provider>
答案 2 :(得分：0)
使用Picasso库从网址高效加载图片。
答案 3 :(得分：0)
请试试这个，
Uri uri=Uri.parse("android.resource://my.package.name/"+R.drawable.image);
imgView.setImageURI(null);
imgView.setImageURI(uri);
希望它会有所帮助。
答案 4 :(得分：0)
尝试使用以下方法
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());
}