android 短视频开发，依靠Kotlin和Handler实现倒计时

android 短视频开发，依靠Kotlin和Handler实现倒计时效果

1、布局文件

<?xml version="1.0" encoding="utf-8"?><br><androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"<br>    xmlns:app="http://schemas.android.com/apk/res-auto"<br>    xmlns:tools="http://schemas.android.com/tools"<br>    android:layout_width="match_parent"<br>    android:layout_height="match_parent"<br>    tools:context=".countDown.CountDownActivity"><br> <br>    <TextView<br>        android:id="@+id/tvCountDown"<br>        android:layout_width="wrap_content"<br>        android:layout_height="wrap_content"<br>        android:text="剩余60秒"<br>        app:layout_constraintStart_toStartOf="parent"<br>        app:layout_constraintEnd_toEndOf="parent"<br>        app:layout_constraintTop_toTopOf="parent"<br>        android:layout_marginTop="24dp"/><br> <br></androidx.constraintlayout.widget.ConstraintLayout>

2、Activity当中逻辑处理

import androidx.appcompat.app.AppCompatActivity<br>import android.os.Bundle<br>import android.os.Handler<br>import com.example.myapplication.R<br>import kotlinx.android.synthetic.main.activity_count_down.*<br> <br>class CountDownActivity : AppCompatActivity() {<br> <br>    private val handler = Handler()<br>    private var mCountNum = 60<br> <br>    override fun onCreate(savedInstanceState: Bundle?) {<br>        super.onCreate(savedInstanceState)<br>        setContentView(R.layout.activity_count_down)<br> <br>        tvCountDown.setOnClickListener {<br>            handler.postDelayed(countDown, 0)<br>        }<br>    }<br> <br>    private val countDown = object : Runnable {<br> <br>        override fun run() {<br> <br>            tvCountDown.text = "剩余" + mCountNum + "秒"<br>            tvCountDown.isEnabled = false<br>            if (mCountNum > 0) {<br>                handler.postDelayed(this, 1000)<br>            } else {<br>                tvCountDown.text = "重新倒计时"<br>                tvCountDown.isEnabled = true<br>                mCountNum = 60<br>            }<br>            mCountNum--<br>        }<br>    }<br>    <br>    private fun removeCountDOwn() {<br>        <br>        handler.removeCallbacks(countDown)<br>    }<br>}