使用MediaStore保存图像，使用错误的名称和扩展名保存

Question

我正在尝试使用MediaStore API来保存图像，但它总是以这个名称保存文件1637955326427.jpg并且文件的大小0 B。

 OutputStream fos;
            ContentResolver resolver = getBaseContext().getContentResolver();
            ContentValues contentValues = new ContentValues();
            contentValues.put(MediaStore.Images.Media.DISPLAY_NAME, "fileName.jpg");
            contentValues.put(MediaStore.Images.Media.MIME_TYPE, "image/jpeg");
            Uri imageUri = resolver.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, contentValues);
            try {
                fos = resolver.openOutputStream(Objects.requireNonNull(imageUri));
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(),list.get(0).getDocfile().getUri());
                if(bitmap!=null){
                    bitmap.compress(Bitmap.CompressFormat.JPEG,100,fos);

                    fos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

<代码>列表。获取（0）。getDocFile（）返回一个文档文件，我也在API 28上测试了这个，谢谢

请注意，此图像已存在于外部存储器中，只需复制即可。

编辑：我删除此代码fos=resolver.openOutputStream（ImageUri）；是重复的。我真的很抱歉。文件工作正常，但盗用了错误的名称。

Answer 1

我删除此代码fos=解析器。openOutputStream（imageUri） 重复。该图像工作正常，但盗取了错误的名称。

关于错误的名称和扩展名，我认为MediaStore不适用于Android 9及更低版本，因为我在Android 11上测试了相同的代码并且运行良好

Answer 2

首先，让我们看看如何获取现有图像的写入权限。请注意，光路不一定存在，但应指向您希望保存文件的位置。

if (!requestPhotoWritePermission(this, getImageUriFromFS(this, new File(photoPath)))) {
        return;
    } else {
        takePicture();
    }

这将对默认摄像机形成覆盖请求

public static Uri getImageUriFromFS(Context c, File file) {
    long id = getFilePathToImageID(file, c);
    Uri fromUri = ContentUris.withAppendedId( MediaStore.Images.Media.EXTERNAL_CONTENT_URI,id);
    return fromUri;
}



public static long getFilePathToImageID(File imagePath, Context context)
{
    Uri mainUri;
    Cursor cursor1 = context.getContentResolver().query(
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
            new String[]{MediaStore.Images.Media._ID},
            MediaStore.Images.Media.DATA + "=? ",
            new String[]{imagePath.getAbsolutePath()}, null);
    long id = 0;
    if (cursor1 != null && cursor1.moveToFirst()) {

        id = cursor1.getLong(cursor1.getColumnIndex(MediaStore.MediaColumns._ID));
        cursor1.close();
    }
    return id;
}

public static boolean requestPhotoWritePermission(Activity activity, Uri fromUri) {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.R) {

        boolean hasPermission = true;
        if (activity.checkUriPermission(fromUri, Binder.getCallingPid(), Binder.getCallingUid(),
                Intent.FLAG_GRANT_WRITE_URI_PERMISSION | Intent.FLAG_GRANT_READ_URI_PERMISSION) != PackageManager.PERMISSION_GRANTED) {
            hasPermission = false;
        }

        List<Uri> uriList = new ArrayList<>();
        uriList.add(fromUri);

        if (!hasPermission) {
            PendingIntent pi = MediaStore.createWriteRequest(activity.getContentResolver(), uriList);
            try {
                activity.startIntentSenderForResult(pi.getIntentSender(), REQUEST_OVERWRITE_PERMISSION_CODE, null, 0, 0, 0);
            } catch (IntentSender.SendIntentException e) {
                e.printStackTrace();
            }
            return false;
        }
        return true;
    }
    return true;
}

这将保留通过摄像头覆盖或创建新图片的权限

然后在你的活动中：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 53) {
        if (resultCode == RESULT_OK) {
            //you'll want to take your picture here and possibly store the uri to your photo for later retrieval
            takePicture();
        }
 }

如果许可请求被接受，这将拍照

要使用默认意图与提供者合影，请执行以下操作：

>

在清单中声明您的提供者

 <provider
     android:name="androidx.core.content.FileProvider"
     android:authorities="${applicationId}.provider"
     android:enabled="true"
     android:exported="false"
     android:grantUriPermissions="true">
     <meta-data
         android:name="android.support.FILE_PROVIDER_PATHS"
         android:resource="@xml/file_paths">
     </meta-data>
 </provider>

1.5：xml文件路径文件：

<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-files-path
    name="internal_images"
    path="files/Pictures" />
<external-files-path
    name="internal_images_alternate"
    path="Pictures" />
<external-path
    name="external"
    path="Documents" />
<external-files-path
    name="external_files"
    path="Documents" />
<cache-path
    name="cache"
    path="Documents" />
<external-cache-path
    name="external_cache"
    path="Documents" />
<files-path
    name="files"
    path="Documents" />
</paths>

上面将允许您保存到文档文件夹。根据需要更换。

利用提供者拍照

public static File dispatchTakePictureIntent(Activity activity, String photoPath) {

     Intent takePictureIntent = getCameraIntentWithUpdatedPackages(activity);
     Uri photoURI = Uri.fromFile(new File(photoPath));

     Uri photoUri = FileProvider.getUriForFile(activity.getApplicationContext(), activity.getApplicationContext().getPackageName() + ".provider", new File(photoPath));

     activity.grantUriPermission(photoURI.getAuthority(), photoUri, Intent.FLAG_GRANT_WRITE_URI_PERMISSION | Intent.FLAG_GRANT_READ_URI_PERMISSION);
     takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoUri);
     //disable strict mode policies
     StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
     StrictMode.setVmPolicy(builder.build());
     activity.startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
     return new File(photoPath);


 return null;

}

编辑：我忘了什么

 public static Intent getCameraIntentWithUpdatedPackages(Context context) {
    List<ResolveInfo> resolveInfo = new ArrayList<>();

    final Intent capturePhoto = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    PackageManager pm = context.getPackageManager();
    resolveInfo = pm.queryIntentActivities(capturePhoto, 0);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
//             For Android 11 we need to add specific camera apps
        // due them are not added during ACTION_IMAGE_CAPTURE scanning...
//            resolveInfo.addAll(getCameraSpecificAppsInfo(context));
    }
    capturePhoto.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);

    return capturePhoto;
}

编辑：按名称更新（在请求覆盖权限后的onActivityResult中）

Uri fromUri = MediaUtils.getImageUriFromFS(this, new File(from));
                ContentResolver contentResolver = getContentResolver();
                ContentValues contentValues = new ContentValues();

                contentValues.put(MediaStore.Files.FileColumns.IS_PENDING, 1);
                contentResolver.update(fromUri, contentValues, null, null);
                contentValues.clear();
                contentValues.put(MediaStore.Files.FileColumns.DISPLAY_NAME, new File(to).getName());
                contentValues.put(MediaStore.Files.FileColumns.IS_PENDING, 0);
                contentResolver.update(fromUri, contentValues, null, null);