Android app first start is very slow and systrace

问题:

I'm currently developing an Android app and trying to improve the start time. In order to do so, I'm using the Systrace tool.

The first time I run the app (right after installed), it takes ~40 seconds to start, and I get this trace:

As you can see, there is a 30 seconds light purple tag with title bindApplication.

After this, I close the app (swiped away from recent activities) and reopen it. This time the bindApplication tag is just 4 seconds long:

• Does anybody know if it's normal for the first run to take so long ?
• What can I do to improve it ?

My guess here is that bindApplication is related somehow to heavy work in the onCreate App method, but I don't see how that could happen. Just in case it helps: in my onCreate I initialize the following libraries: Parse, Crashlytics, Timber, ParseFacebookUtils and Google Analytics.

EDIT:

Here is the App subclass code:

public class MyApp extends Application {

  private Tracker tracker;

  @Override public void onCreate() {
    super.onCreate();
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
      Trace.beginSection("MyApp");
    }
    Fabric.with(this, new Crashlytics());

    // Parse setup
    Parse.enableLocalDatastore(this);
    ParseObject.registerSubclass( ... );

    Parse.Configuration.Builder parseConfigBuilder = new Parse.Configuration.Builder(this).applicationId(
        getString(R.string.parse_application_id))
        .server(getString(R.string.parse_server_url));

    if (BuildConfig.DEBUG) {
      // add logs
      Timber.plant(new DebugTree());
      Parse.setLogLevel(Parse.LOG_LEVEL_VERBOSE);
      parseConfigBuilder.addNetworkInterceptor(new ParseLogInterceptor());
    }

    Parse.initialize(parseConfigBuilder.build());

    ParseFacebookUtils.initialize(this);

    ParseInstallation.getCurrentInstallation().saveInBackground();

    AnalyticsManager.getInstance().init(this);
    AnalyticsManager.getInstance().debugMode(BuildConfig.DEBUG);

    if (BuildConfig.DEBUG) {
      StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
          .detectAll()
          .penaltyLog()
          .build());
      StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder().
          detectAll()
          .penaltyLog()
          .build());
    }

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR2) {
      Trace.endSection();
    }
  }

  /**
   * Gets the default {@link Tracker} for this {@link Application}.
   * @return tracker
   */
  synchronized public Tracker getDefaultTracker() {
    if (tracker == null) {
      GoogleAnalytics analytics = GoogleAnalytics.getInstance(this);
      // To enable debug logging use: adb shell setprop log.tag.GAv4 DEBUG
      tracker = analytics.newTracker(R.xml.global_tracker);
    }
    return tracker;
  }
}

回答1:

it is problem of instant run. i had once this kind of problem and i solve if by disable instant run. here is same question and you can find your answer in comment of question.

First launch take long time (ClassLoader referenced unknown path)