[AndroidStudio] ProgressBar

class MainActivity : AppCompatActivity() {

	// viewBinding
    val binding by lazy {
        ActivityMainBinding.inflate(layoutInflater)
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // viewBinding
        setContentView(binding.root)

		// 4초동안 실행
        thread(start = true) {
            Thread.sleep(4000)
            // 화면에서 실행하게 만들기
            runOnUiThread {
                showProgress(false)
            }
        }
    }

    fun showProgress(show: Boolean) {
        binding.progressBar.visibility = if (show) View.VISIBLE else View.GONE
        // 로딩이 끝나면 토스트 메세지와 함께 이미지 띄우기
        if (show) binding.textView.visibility = View.VISIBLE
        else {
            Toast.makeText(this@MainActivity, "Download complete!", Toast.LENGTH_SHORT)
            binding.imageView.visibility = View.VISIBLE
        }
    }
}