How to implement app self-update from downloaded apk?

Question

I'm working with OTA update for the app. It works like this: I click "check update", it checks it, downloads if exists and save apk on the device. Then I can install it, but of course I have a confirmation dialog. I need to do it silently and restart the app.

I want to make it auto-install when downloading finished. So I just click and if there's some update the app restarts in new version. I can't figure out how to do it. The device is rooted.

Answer 1

The following code works only on roodted devices!

private int installApk(File file) {
    if (!file.exists()) throw new IllegalArgumentException();

    Process process = null;

    try {
        process = Runtime.getRuntime().exec(new String[]{"su", "-c", "pm install -r " + file
                .getAbsolutePath()});
        int exitCode = process.waitFor();
        if (exitCode != 0) throw new RuntimeException();
    } catch (IOException | InterruptedException exception) {
        Log.w(getClass().getSimpleName(), exception);
    }

    return (process == null) ? Integer.MIN_VALUE : process.exitValue();
}