Simple Android App > Activity Lifecycle

package com.trollglodita.crystalballs;

import android.app.Activity;
import android.graphics.drawable.AnimationDrawable;
import android.hardware.Sensor;
import android.hardware.SensorManager;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.animation.AlphaAnimation;
import android.widget.ImageView;
import android.widget.TextView;

import com.trollglodita.crystalballs.ShakeDetector.OnShakeListener;

public class MainActivity extends Activity {

public static final String TAG = MainActivity.class.getSimpleName();

private CrystalBall mCrystalBall = new CrystalBall();
private TextView mAnswerLabel;
private ImageView mCrystalBallImage;
private SensorManager mSensorManager;
private Sensor mAccelerometer;
private ShakeDetector mShakeDetector;

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

    // Assign the Views from the layout file
    mAnswerLabel = (TextView) findViewById(R.id.textView1);
    mCrystalBallImage = (ImageView) findViewById(R.id.imageView1);

    mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    mAccelerometer =     mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    mShakeDetector = new ShakeDetector(new OnShakeListener() {

        @Override
        public void onShake() {
            handleNewAnswer();

        }
    });

    // Toast.makeText(this, "Yay! Our activity was created", Toast.LENGTH_LONG).show();

    Log.d(TAG, "We're logging from the onCreate() method!");


    @Override
    public void onResume(){
        super.onResume();
        mSensorManager.registerListener(mShakeDetector, mAccelerometer, 
                SensorManager.SENSOR_DELAY_UI);
    }

    @Override
    public void onPause(){
        super.onPause();
        mSensorManager.unregisterListener(mShakeDetector);
    }
}


private void animateCrystalBall() {
    mCrystalBallImage.setImageResource(R.drawable.ball_animation);
    AnimationDrawable ballAnimation = (AnimationDrawable) mCrystalBallImage.getDrawable();
    if (ballAnimation.isRunning()){
        ballAnimation.stop();
    }
    ballAnimation.start();
}

private void animateAnswer(){
    AlphaAnimation fadeInAnimation = new AlphaAnimation(0, 1);
    fadeInAnimation.setDuration(1500);
    fadeInAnimation.setFillAfter(true);

    mAnswerLabel.setAnimation(fadeInAnimation);
}

private void playSound(){
    MediaPlayer player = MediaPlayer.create(this, R.raw.crystal_ball);
    player.start();
    player.setOnCompletionListener(new OnCompletionListener() {

        @Override
        public void onCompletion(MediaPlayer mp) {
            mp.release();               
        }
    });
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}


private void handleNewAnswer() {
    String answer = mCrystalBall.getAnAnswer();

    // Update the label with our dynamic answer
    mAnswerLabel.setText(answer);

    animateCrystalBall();
    animateAnswer();
    playSound();
}

}