Boil an egg app - step by step (step 3 – code)
After reviewing part 2 of the tutorial, it’s time for coding. let’s get started.
In the main activity class we’ll have the following things to do:
1. set some private variables to be accessed from different places in the class.
2. bind some variables to views from the xml reviewed in part 2
3. set listeners for the different buttons on the screen
4. handle timer changing and displaying time remained
let’s elaborate on this :
1. initialize some variables in the main class, place those prior to the onCreate() method:
private Button btnSmallEgg,btnMediumEgg,btnLargeEgg;
private Button btnCookAnEggTimer,btnResetTimer;
private TextView btnSoftEgg,btnHardEgg;
private TextView tvTimer,tvTimerLabel;
private TextView tvChooseEggSize,tvChooseEggType,tvIntro ;
long minutes;
long seconds;
long maxTimer=600000;
long lastKnowTimer=600000;
final static int boilTimeHardLargeEgg=600000; // 10 minutes
final static int boilTimeSoftLargeEgg=300000; // 6 minutes
final static int boilTimeSoftMediumEgg=200000; // 4 minutes
final static int boilTimeHardMediumEgg=500000; // 4 minutes
final static int boilTimeSoftSmallEgg=100000; // 4 minutes
final static int boilTimeHardSmallEgg=250000; // 4 minutes
private int selected = 0; //default soft eggs
private int selectedSize=1;
private CountDownTimer timer;
2. bind some variables to the different UI controls from the XML, we’ll extract it to a
single method called init()
private void init() {
tvTimerLabel = (TextView)findViewById(R.id.main_eggs_timer_label);
tvChooseEggSize = (TextView)findViewById(R.id.tvChooseEggSize);
tvChooseEggType = (TextView)findViewById(R.id.tvChooseEggType);
tvIntro = (TextView)findViewById(R.id.intro);
btnCookAnEggTimer = (Button)findViewById(R.id.startCookingAnEgg);
btnResetTimer = (Button)findViewById(R.id.resetCookingAnEgg);
btnSmallEgg = (Button)findViewById(R.id.btnSmallEgg);
btnMediumEgg = (Button)findViewById(R.id.btnMediumEgg);
btnLargeEgg = (Button)findViewById(R.id.btnLargeEgg);
btnSoftEgg = (TextView)findViewById(R.id.btnSoftEgg);
btnHardEgg = (TextView)findViewById(R.id.btnHardEgg);
tvTimer = (TextView)findViewById(R.id.tvTimer);
setInitialValues();
}
private void setInitialValues() {
btnResetTimer.setEnabled(false);
btnSmallEgg.setBackgroundResource(R.drawable.egg_m_not_checked);
btnMediumEgg.setBackgroundResource(R.drawable.egg_l);
btnLargeEgg.setBackgroundResource(R.drawable.egg_xl_not_checked);
}
3. set listeners for the buttons:
//Listeners for all eggs
btnSmallEgg.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
btnSmallEgg.setBackgroundResource(R.drawable.egg_m);
btnMediumEgg.setBackgroundResource(R.drawable.egg_l_not_checked);
btnLargeEgg.setBackgroundResource(R.drawable.egg_xl_not_checked);
selectedSize=0;
}
});
btnMediumEgg.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
btnSmallEgg.setBackgroundResource(R.drawable.egg_m_not_checked);
btnMediumEgg.setBackgroundResource(R.drawable.egg_l);
btnLargeEgg.setBackgroundResource(R.drawable.egg_xl_not_checked);
selectedSize=1;
}
});
btnLargeEgg.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
btnSmallEgg.setBackgroundResource(R.drawable.egg_m_not_checked);
btnMediumEgg.setBackgroundResource(R.drawable.egg_l_not_checked);
btnLargeEgg.setBackgroundResource(R.drawable.egg_xl);
selectedSize=2;
}
});
// listener for "cook" button
btnCookAnEggTimer.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
tvTimer.clearAnimation();
tvTimerLabel.setVisibility(View.VISIBLE);
btnCookAnEggTimer.setCompoundDrawablesWithIntrinsicBounds(0, 0,R.drawable.timer_disabled , 0);
btnResetTimer.setEnabled(true);
btnResetTimer.setCompoundDrawablesWithIntrinsicBounds(0, 0, R.drawable.timer_red, 0);
btnCookAnEggTimer.setEnabled(false);
if (selected==1)
{
switch (selectedSize) {
case 0:
InitializeTimer(boilTimeHardSmallEgg);
break;
case 1:
InitializeTimer(boilTimeHardMediumEgg);
break;
case 2:
InitializeTimer(boilTimeHardLargeEgg);
break;
}
}
if (selected==0)
{
switch (selectedSize) {
case 0:
InitializeTimer(boilTimeSoftSmallEgg);
break;
case 1:
InitializeTimer(boilTimeSoftMediumEgg);
break;
case 2:
InitializeTimer(boilTimeSoftLargeEgg);
break;
default:
break;
}
}
timer.start();
}
});
// listener for reset timer button
btnResetTimer.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
timer.cancel();
InitializeTimer(maxTimer);
btnCookAnEggTimer.setEnabled(true);
tvTimer.setText("");
tvTimerLabel.setVisibility(View.GONE);
btnResetTimer.setEnabled(false);
// Change the icon inside the buttons
btnCookAnEggTimer.setCompoundDrawablesWithIntrinsicBounds(0, 0,R.drawable.timer_green, 0);
btnResetTimer.setCompoundDrawablesWithIntrinsicBounds(0, 0,R.drawable.timer_disabled, 0);
btnResetTimer.setEnabled(false);
}
});
btnHardEgg.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
selected=1;
btnHardEgg.setTextColor(getResources().getColor(R.color.orange));
btnSoftEgg.setTextColor(getResources().getColor(R.color.gray));
}
});
btnSoftEgg.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
selected=0;
btnSoftEgg.setTextColor(getResources().getColor(R.color.orange));
btnHardEgg.setTextColor(getResources().getColor(R.color.gray));
}
});
4. set timers depending on selections and updating the ui controls with time remaining:
private void InitializeTimer(long lastknowtimer) {
timer = new CountDownTimer(lastknowtimer, 1000) {
@Override
public void onTick(long lastknowtimer) {
int seconds = (int) (lastknowtimer / 1000) % 60 ;
int minutes = (int) ((lastknowtimer / (1000*60)) % 60);
tvTimerLabel.setVisibility(View.VISIBLE);
String timeLeft = (seconds<10) ? minutes + ":0" + seconds : minutes + ":" + seconds;
tvTimer.setText(timeLeft);
}
@Override
public void onFinish() {
tvTimer.setText("finished");
MediaPlayer mPlayer = MediaPlayer.create(getApplicationContext(), R.raw.chicken);
try {
mPlayer.prepare();
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
mPlayer.start();
}
};
}
and that’s it,
patch it all up together and your'e good to go 
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