Android install apk with Intent.VIEW_ACTION not working with File provider

This could be the problem, you have

intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION); 

in your example it should be

install.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);

as install is the name of the intent.

I had this problem when calling start activity.after pausing my current activity, it suddenly came back and called onResume. like nothing happened. my problem was with this permission in manifest:

 <uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />

almost no one mentioned that. so remember this. in sdk >= 24 you need to use provider because it needs an intent starting with file:/// below sdk 24 you should give uri starting with content:/// so that's why we need file provider for sdk 24 and above. I don't think I need to write any codes for this as @just_user has written correct answer. https://stacklearn.ir

After a lot of trying I have been able to solve this by creating different Intents for anything lower than Nougat as using the FileProvider to create an install intent with Android Versions before Nougat causes the error:

ActivityNotFoundException: No Activity found to handle Intent { act=android.intent.action.INSTALL_PACKAGE dat=content://XXX.apk flg=0x1 }

While using a normal Uri on Android Nougat creates the following error:

FileUriExposedException: file:///XXX.apk exposed beyond app through Intent.getData()

My solution which is working for me with Android N on the emulator and a phone running Android M.

File toInstall = new File(appDirectory, appName + ".apk");
Intent intent;
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
    Uri apkUri = FileProvider.getUriForFile(activity, BuildConfig.APPLICATION_ID + ".fileprovider", toInstall);
    intent = new Intent(Intent.ACTION_INSTALL_PACKAGE);
    intent.setData(apkUri);
    intent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
} else {
    Uri apkUri = Uri.fromFile(toInstall);
    intent = new Intent(Intent.ACTION_VIEW);
    intent.setDataAndType(apkUri, "application/vnd.android.package-archive");
    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
}
activity.startActivity(intent);

UPDATE FOR Android Nougat 7.1:

You also need to add the permission REQUEST_INSTALL_PACKAGES in your manifest. Its available from Api Level 23 (Android 6.0 Marshmallow) and required from Level 25 (Android 7.1 Nougat).

UPDATE:

Remember to request the permissions for read and write to external storage if the file you try to install is on the external storage. And also to set up a correct FileProvider for Android Nougat and above.

First check if you have write permission by calling canReadWriteExternal() below, if not call requestPermission() before:

private static final int REQUEST_WRITE_PERMISSION = 786;

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    if (requestCode == REQUEST_WRITE_PERMISSION && grantResults[0] == PackageManager.PERMISSION_GRANTED)
        Toast.makeText(this, "Permission granted", Toast.LENGTH_LONG).show();
}

private void requestPermission() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
        requestPermissions(new String[]{ Manifest.permission.WRITE_EXTERNAL_STORAGE}, REQUEST_WRITE_PERMISSION);
}

private boolean canReadWriteExternal() {
    return Build.VERSION.SDK_INT < Build.VERSION_CODES.M ||
            ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED;
}

Here is an example of a file provider for the Download folder on the external storage. AndroidManifest.xml:

<application ... >
    ...

    <provider
        android:name="android.support.v4.content.FileProvider"
        android:authorities="${applicationId}.fileprovider"
        android:exported="false"
        android:grantUriPermissions="true">
        <meta-data
            android:name="android.support.FILE_PROVIDER_PATHS"
            android:resource="@xml/filepaths" />
    </provider>
</application>

resources/xml/filepaths.xml:

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path name="external_download" path="Download"/>
</paths>

If you get an error while installing the .apk saying something like "There is a problem parsing the package." it could be that you haven't asked for the read/write permission or the file you try to install doesn't exist or is corrupt.

UPDATE FOR Android Oreo 8.0:

You have to check if current application is allowed to install the APK on Android Oreo 8.0 or above.

You can check if your app is allowed to install APK by using canRequestPackageInstalls method of PackageManager class. If it returns false, then you can launch intent with ACTION_MANAGE_UNKNOWN_APP_SOURCES action to launch settings dialog where user can allow the app to install APKs.

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O 
        && !getPackageManager().canRequestPackageInstalls()) {
    Intent unknownAppSourceIntent = new Intent()
            .setAction(Settings.ACTION_MANAGE_UNKNOWN_APP_SOURCES)
            .setData(Uri.parse(String.format("package:%s", getPackageName())));

    unknownAppSourceDialog.launch(unknownAppSourceIntent);
} else {
    // App already have the permission to install so launch the APK installation.
    startActivity(intent);
}

Make sure you add the following code to your activity to receive the result of intent.

ActivityResultLauncher<Intent> unknownAppSourceDialog = registerForActivityResult(
    new ActivityResultContracts.StartActivityForResult(),
    result -> {
        if (result.getResultCode() == Activity.RESULT_OK) {
            // User has allowed app to install APKs
            // so we can now launch APK installation.
            startActivity(intent);
        }
    });

You should note that for API < 24 you need to use:

        setDataAndType(Uri.fromFile(apkFile), "application/vnd.android.package-archive")

instead of setting data and type separately:

data = Uri.fromFile(apkFile)
    type = "application/vnd.android.package-archive"

otherwise, you will get ActivityNotFoundException