Day71 of #100DaysOfCode

Day71 of #100DaysOfCode

Hii folks 🙌

Today I will be continuing the same pathway in which we’ll attach the LiveData to score and wordCount.

Unit 3: Navigation

Pathway 2: Architecture componentsSource

https://developer.android.com/courses/android-basics-kotlin/course

Use LiveData with ViewModel

We will learn how to wrap any data with LiveData , by converting the current word in the GameViewModel to LiveData . Later we will add an observer to these LiveData objects.

MutableLiveData is the mutable version of the LiveData, that is, the value of the data stored within it can be changed.

• In GameViewModel, we will change the type of the variable _currentScrambledWord to MutableLiveData<String>. LiveData and MutableLiveData are generic classes, so we need to specify the type of data that they hold.
• Now we will change the variable type of _currentScrambledWord to val because the value of the LiveData/MutableLiveData object will remain the same, and only the data stored within the object will change.

private val _currentScrambledWord = MutableLiveData<String>()

• Now we will change the backing field, currentScrambledWord type to LiveData<String>, because it is immutable.

val currentScrambledWord: LiveData<String>
   get() = _currentScrambledWord

• To access the data within a LiveData object, we use the value property. In GameViewModel inside the getNextWord() method, within the else block, change the reference of _currentScrambledWord to _currentScrambledWord.value.

private fun getNextWord() {
 ...
   } else {
       _currentScrambledWord.value = String(tempWord)
       ...
   }
}

Now we will attach the observer to the LiveData object

private fun onSubmitWord() {
    val playerWord = binding.textInputEditText.text.toString()

    if (viewModel.isUserWordCorrect(playerWord)) {
        setErrorTextField(false)
        if (!viewModel.nextWord()) {
            showFinalScoreDialog()
        }
    } else {
        setErrorTextField(true)
    }
}

• And, we will attach an observer for currentScrambledWord LiveData. In GameFragment at the end of the callback onViewCreated(), call the observe() method on currentScrambledWord.

// Observe the currentScrambledWord LiveData.
viewModel.currentScrambledWord.observe()

• Now we will add a lambda as a second parameter with newWord as a function parameter. The newWord will contain the new scrambled word value.

// Observe the scrambledCharArray LiveData, passing in the LifecycleOwner and the observer.
viewModel.currentScrambledWord.observe(viewLifecycleOwner,
   { newWord ->
   })

• In the function body of the lambda expression, we will assign newWord to the scrambled word text view.

// Observe the scrambledCharArray LiveData, passing in the LifecycleOwner and the observer.
viewModel.currentScrambledWord.observe(viewLifecycleOwner,
   { newWord ->
       binding.textViewUnscrambledWord.text = newWord
   })

That is all for Day71 ✅

Thanks for reading, See you tomorrow!

If you are reading my #100Days Journey, feel free to drop by ;)

The Journey of #100DaysOfCode (@im_Kushagra)