直接上代码

<video id="myVideo" class="course-head-img video" :src="currentVideo.url" autoplay controls @timeupdate="videoTimeUpdateEvent" @fullscreenchange="videoControl">
 </video>
 </video>
// 先声明
mounted() {
   获取当前视频
    this.videoContext = uni.createVideoContext('myVideo', this)
},

// 当视频进入和退出全屏时触发
videoControl(e) {
    console.log('eee', e.detail.fullScreen)
    if (e.detail.fullScreen) {

    }
    if (!e.detail.fullScreen) {
        this.videoContext.pause();    //终止视频
        this.popupvideo = false  //关闭视频弹窗
    }
},


// 打开视频直接进入全屏(横屏)
this.popupvideo = true  //打开视频弹窗
this.videoContext = uni.createVideoContext('myVideo', this);
this.videoContext.requestFullScreen();    打开视频直接进入全屏(横屏)
this.videoContext.requestFullScreen({direction: 0});    打开视频直接进入全屏(半黑屏)

上述选其一即可
this.videoContext.play()   视频播放

注:(不建议直接使用@play方法进入全屏,虽可实现进入全屏横屏,但无法直接收回全屏横屏,收回需先暂停视频再点击收回,直接收回会与视频播放暂停有冲突)