我已授予权限,但是Object() or Object()
返回此错误:
BitmapFactory.decodeFile()
我想从图库中获取最后一张图像,并将其保存到另一个文件中。我在运行它的Android P测试设备上对其进行了测试。但它会在具有Android版本Q(API级别29)的android模拟器中返回此错误。怎么了?
这些是我的代码段:
E/BitmapFactory: Unable to decode stream: java.io.FileNotFoundException: /storage/emulated/0/DCIM/Camera/IMG_20200130_165131.jpg: open failed: EACCES (Permission denied)
writeStoragePermissionGranted();
BitmapFactory.Options options = null;
Bitmap bm = null;
String[] projection = new String[]{
MediaStore.Images.ImageColumns._ID,
MediaStore.Images.ImageColumns.DATA,
MediaStore.Images.ImageColumns.BUCKET_DISPLAY_NAME,
MediaStore.Images.ImageColumns.DATE_TAKEN,
MediaStore.Images.ImageColumns.MIME_TYPE,
MediaStore.Images.ImageColumns.DISPLAY_NAME,
};
final Cursor cursor = this.getContentResolver()
.query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, projection, null,
null, MediaStore.Images.ImageColumns.DATE_TAKEN + " DESC");
if (cursor.moveToFirst()) {
final ImageView imageView = (ImageView) findViewById(R.id.pictureView);
String imageLocation = cursor.getString(1);
File imageFile = new File(imageLocation);
if (imageFile.exists()) {
options = new BitmapFactory.Options();
options.inSampleSize = 2;
try {
bm = BitmapFactory.decodeFile(imageLocation, options);
} catch(Exception e) {
e.printStackTrace();
}
}
imageView.setImageBitmap(bm);
try {
saveImage(bm,"NAME" );
} catch (IOException e) {
e.printStackTrace();
}
}
功能:
writeStoragePermissionGranted()
和清单权限:
public void writeStoragePermissionGranted() {
if (Build.VERSION.SDK_INT >= 23) {
if (checkSelfPermission(android.Manifest.permission.WRITE_EXTERNAL_STORAGE)
== PackageManager.PERMISSION_GRANTED) {
startPeriodicRequest();
} else {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, Constants.REQUEST_CODE_WRITE_EXTERNAL_STORAGE_PERMISSION);
}
} else {
return;
}
}
我知道对此有很多疑问。但是没有人在Android模拟器版本Q上工作。另一方面,此代码在android pie(API级别28)上有效。
答案 0 :(得分:21)
在清单的应用程序块中添加android:requestLegacyExternalStorage="true"
实际上可以解决该问题!
答案 1 :(得分:10)
在Android 10上,他们引入了“范围存储”的概念,这样一来,您将无法再使用其路径打开图像。您可以获取更多信息HERE。
因此,现在您必须使用其ParcelFileDescriptor
和其Uri
对其进行解码。
您可以:
final Cursor cursor = this.getContentResolver().query(MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
projection, null, null, MediaStore.Images.ImageColumns.DATE_TAKEN + " DESC");
if (cursor.moveToFirst()) {
final ImageView imageView = (ImageView) findViewById(R.id.pictureView);
if (Build.VERSION.SDK_INT >= 29) {
// You can replace '0' by 'cursor.getColumnIndex(MediaStore.Images.ImageColumns._ID)'
// Note that now, you read the column '_ID' and not the column 'DATA'
Uri imageUri= ContentUris.withAppendedId(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, cursor.getInt(0));
// now that you have the media URI, you can decode it to a bitmap
try (ParcelFileDescriptor pfd = this.getContentResolver().openFileDescriptor(mediaUri, "r")) {
if (pfd != null) {
bitmap = BitmapFactory.decodeFileDescriptor(pfd.getFileDescriptor());
}
} catch (IOException ex) {
}
} else {
// Repeat the code you already are using
}
}
答案 2 :(得分:0)
您只需将 android:requestLegacyExternalStorage="true"
添加到 Application
中的 Manifest.xml
标签。
希望下面的代码能帮到你。
Manifest.xml
在清单文件中添加以下内容:
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />
同时添加:
在 Manifest 的 Application 标签中添加这个。
android:requestLegacyExternalStorage="true"
打开图库获取图片:
private void openImagePicker() {
MyDatePicker datePicker = new MyDatePicker();
datePicker.show(getSupportFragmentManager(), "DATE PICK");
}
启动 ActivityForResult:
onActivityResult
您将获得结果对象,通过您将获得图像原始 uri。
ActivityResultLauncher<Intent> galleryResultLauncher = registerForActivityResult(
new ActivityResultContracts.StartActivityForResult(),
new ActivityResultCallback<ActivityResult>() {
@Override
public void onActivityResult(ActivityResult result) {
if (result.getResultCode() == Activity.RESULT_OK) {
Intent data = result.getData();
imageURi = data.getData();
image.setVisibility(View.VISIBLE);
String path = getPath(imageURi);
File file = new File(path);
if (file.exists()) {
Bitmap myBitmap = BitmapFactory.decodeFile(file.getAbsolutePath());
image.setImageBitmap(myBitmap);
}
}
}
});
获取图片的绝对路径:
public String getPath(Uri uri) {
String[] projection = {MediaStore.Images.Media.DATA};
Cursor cursor = managedQuery(uri, projection, null, null, null);
if (cursor != null) {
int column_index = cursor
.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
cursor.moveToFirst();
return cursor.getString(column_index);
} else return null;
}