selmanon

mkdir alpha
cd alpha
mkdir data
printf 'a' > data/letter.txt
git init
git add data/letter.txt
printf '1234' > data/number.txt
git add data
printf '1' > data/number.txt
git add data

selmanon

# Package by features

The directory structure is the very first thing encountered by a programmer when browsing source code. Everything flows from it. Everything depends on it. It is clearly one of the most important aspects of your source code.


### Gains and Benefits
* By looking at the structure you can already tell what the app is all about (figure 1);
* Higher modularity;
* Easier code navigation;
* Higher level of abstraction;

selmanon

## Note : 
We will use MVP as default architecture cause it's easy to implement comparing to MVVM.
Instead we will implement some features with MVVM architecture.

## Why we need an Architecture ?
1. The Android API is tightly coupled.
2. Make the app easy to test (the must important part).
3. Make the app modular.
4. Make app change/fix easy.

selmanon

inline fun<reified T:Activity>Context.startActivity() {
        val intent = Intent(this, T:: class.java)
        startActivity(intent)
    }
        
startActivity<DetailActivity>()

selmanon

testLoginError() 
testLoginSuccess()
testLoginWithoutStudentNameAndPassword()

selmanon

  @Test
  public void testSuccessfulLogin() {
    // Aragnge
    final LoginViewModel vm = new LoginViewModel(environment());

    final TestSubscriber<Void> loginSuccess  = new TestSubscriber<>();
    vm.outputs.loginSuccess().subscribe(loginSuccess);

    vm.inputs.email("hello@kickstarter.com");
    vm.inputs.password("danisawesome");

selmanon

Observable
	.just(1, 2, 3, 4, 5)
	.filter(new Func1<Integer, Boolean>() {
		@Override
		public Boolean call(Integer integer) {
			return integer % 2 != 0;
		}
	}).subscribe(new Observer<Integer>() {
		@Override
		public void onSubscribe(Disposable d) {

selmanon

Observable
	.just(1, 2, 3, 4, 5)
	.filter(integer -> integer % 2 != 0)
  .subscribe(
	integer -> Log.i(TAG, String.valueOf(integer)),
	error -> Log.e(TAG, "Error"),
    	() -> Log.i(TAG, "No more results")
);

selmanon

if (product.getType == productType.TYPE_A) {
     // ...
} else if (product.getType == productType.TYPE_B) {
    // ...
} else if (...) {
    // ...
}
else {
    // ... 
}

selmanon

import kotlin.math.ceil

data class Cell(val i: Int, val j: Int, val isAlive: Boolean) {
    operator fun get(i: Int, j: Int): Int {
        if ((i < 0 || i >= 2) || (j < 0 || j >= 2)) return 0
        else
            return 0
    }
}