fix bug 1058

[haodi19]

Description

Modify PdfToImageFragment.java: In method onImagesInGalleryClick(), the original image URI is an invalid and fixed URI "content:///storage/emulated/0/PDFfiles/". I replace this URI with the URI of the generated image, and create an util method file2Content in FileUtils.java to convert URI starts with"file://" to URI starts with "content://", and then save the images to the gallery. Now "view images in gallery" button can show generated images in gallery.

Fixes #1058

Type of change

Just put an x in the [] which are valid.

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Tested on Pixel 2 API 30 in Android Studio Please describe the tests that you ran to verify your changes.

• [x] ./gradlew assembleDebug assembleRelease
• [x] ./gradlew checkstyle

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my own code
• [x] I have commented my code, particularly in hard-to-understand areas
• [x] I have made corresponding changes to the documentation
• [x] My changes generate no new warnings

[codeclimate[bot]]

Code Climate has analyzed commit ea1cfcb3 and detected 4 issues on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	4

View more on Code Climate.

[Swati4star]

Can you fix merge conflicts?