Measure Android app startup time

Question

What is the most precise way to measure startup time of an Android app?

By startup time I mean the difference between 2. and 3. :

1. The app process is no

Answer 1

It is possible to implement time tracking using the next code:

Override your Application:

public class CustomApplication extends Application {
    public final static long APP_START_TIME = System.currentTimeMillis();

    /**
     * Do all other application stuff
     */
}

And add few rows to your main Activity:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final View contentView = findViewById(android.R.id.content);
        contentView.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                if (Build.VERSION.SDK_INT >= 16) {
                    contentView.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                } else {
                    contentView.getViewTreeObserver().removeGlobalOnLayoutListener(this);
                }
                long launchTime = System.currentTimeMillis() - CustomApplication.APP_START_TIME;
                Log.e("TEST", "App launch time = " + launchTime);
            }
        });
    }
}

And don't forget to define your custom application in Manifest:

Important: You have to kill your application before launch, because Application stores static variable which tracks initial time.