Android Activity Lifecycle

By Manoj Kumar

Introduction

Android Activity Lifecycle is descrived in following diagram. This project helps in understanding these events.

How to Run

1. Prerequisite: Android Studio, some Java knowledge
2. Download or clone project code and open in Android studio.
3. Run in Nexus 5X API 26 emulator.

Technologies Used

1. Java.
2. Android Studio

Application Screenshots

Main Screen with event logs

   public class ActivityA extends Activity {

    private String mActivityName;
    private TextView mStatusView;
    private TextView mStatusAllView;
    private StatusTracker mStatusTracker = StatusTracker.getInstance();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_a);
        mActivityName = getString(R.string.activity_a);
        mStatusView = (TextView)findViewById(R.id.status_view_a);
        mStatusAllView = (TextView)findViewById(R.id.status_view_all_a);
        mStatusTracker.setStatus(mActivityName, getString(R.string.on_create));
        Utils.printStatus(mStatusView, mStatusAllView);
    }

    @Override
    protected void onStart() {
        super.onStart();
        mStatusTracker.setStatus(mActivityName, getString(R.string.on_start));
        Utils.printStatus(mStatusView, mStatusAllView);
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        mStatusTracker.setStatus(mActivityName, getString(R.string.on_restart));
        Utils.printStatus(mStatusView, mStatusAllView);
    }

    @Override
    protected void onResume() {
        super.onResume();
        mStatusTracker.setStatus(mActivityName, getString(R.string.on_resume));
        Utils.printStatus(mStatusView, mStatusAllView);
    }

    @Override
    protected void onPause() {
        super.onPause();
        mStatusTracker.setStatus(mActivityName, getString(R.string.on_pause));
        Utils.printStatus(mStatusView, mStatusAllView);
    }

    @Override
    protected void onStop() {
        super.onStop();
        mStatusTracker.setStatus(mActivityName, getString(R.string.on_stop));
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mStatusTracker.setStatus(mActivityName, getString(R.string.on_destroy));
        mStatusTracker.clear();
    }

    public void startDialog(View v) {
        Intent intent = new Intent(ActivityA.this, DialogActivity.class);
        startActivity(intent);
    }

    public void startActivityB(View v) {
        Intent intent = new Intent(ActivityA.this, ActivityB.class);
        startActivity(intent);
    }

    public void startActivityC(View v) {
        Intent intent = new Intent(ActivityA.this, ActivityC.class);
        startActivity(intent);
    }

    public void finishActivityA(View v) {
        ActivityA.this.finish();
    }
}

Dialog Popup.

Refrence

• Android Activity Lifecycle
• SJSU.edu

Thank You

Manoj Kumar

Solutions Architect