Day 14 | 同步与非同步- Handler类别

Handler类别

使不同Thread沟通的机制，将Thread要传递的讯息放入Message类别，透过Handler与另一个Thread沟通，让另一个Thread从类别取得讯息

class MainActivity : AppCompatActivity(){
	//Step1:建立Handler物件接受讯息
	private val handler = Handler(Looper.getMainLooper()) { msg ->
		when (msg.what) { //判断msg的编号
			1 -> {
				//执行於Main Thread
			}
		}
		return@Handeler true
	}

	override fun onCreate(savedInstanceState: Bundle?){
		super.onCreate(savedInstanceState)
		setContentView(R.layout.activity_main)
		Thread{
			//执行於Background Thread
			//Step2:建立Message物件并加入编号
			val msg = Message()
			msg.what = 1
			//Step3:透过sendMessage传送讯息
			handler.sendMessage(msg)
		}.start()
	}
}