Open an image using URI in Android's default gallery image viewer

Accepted answer was not working for me,

What had worked:

Intent intent = new Intent();
intent.setAction(Intent.ACTION_VIEW);
intent.setDataAndType(Uri.parse("file://" + "/sdcard/test.jpg"), "image/*");
startActivity(intent);

If your app targets Android N (7.0) and above, you should not use the answers above (of the "Uri.fromFile" method), because it won't work for you.

Instead, you should use a ContentProvider.

For example, if your image file is in external folder, you can use this (similar to the code I've made here) :

File file = ...;
final Intent intent = new Intent(Intent.ACTION_VIEW)//
                                    .setDataAndType(VERSION.SDK_INT >= VERSION_CODES.N ?
                                                    FileProvider.getUriForFile(this,getPackageName() + ".provider", file) : Uri.fromFile(file),
                            "image/*").addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

manifest:

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

res/xml/provider_paths.xml :

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <!--<external-path name="external_files" path="."/>-->
    <external-path
        name="files_root"
        path="Android/data/${applicationId}"/>
    <external-path
        name="external_storage_root"
        path="."/>
</paths>

If your image is in the private path of the app, you should create your own ContentProvider, as I've created "OpenFileProvider" on the link.

Ask myself, answer myself also:

startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("content://media/external/images/media/16"))); /** replace with your own uri */

It will also ask what program to use to view the file.