uniapp 开发小程序 自定义导航栏 电脑端小程序不展示返回按钮

<template>
	<view>
		<cu-custom :bgColor="bgColors" :isBack="false">
			<!-- <block slot="backText">返回</block> -->
			<block slot="content" style="color: #333">
				<view class="navBar" :class="[bgColor == 'bg-white' ? 'whiteBar' : '', trans == true ? 'transp' : '']">
					<u-icon v-if="!isWindow" name="arrow-left" :color="bgColor == 'bg-white' ? '#000' : '#fff'" size="19" @tap="back"></u-icon>
					<u-line v-if="!isWindow" direction="column" color="#fff" :hairline="false" length="16" margin="0 10px"></u-line>
					<view class="">
						<u-icon name="list" :color="bgColor == 'bg-white' ? '#000' : '#fff'" size="19" @tap="show = !show"></u-icon>
						<view class="listBox" v-if="show">
							<view class="" @tap.stop="goTo('home')">首页</view>
							<view class="" @tap.stop="goTo('supply')">大厅</view>
							<view class="" @tap.stop="goTo('video')">视频</view>
							<view class="" @tap.stop="goTo('news')">资讯</view>
						</view>
						<view class="mask" v-if="show" @touchstart="show = false"></view>
					</view>
				</view>
				<view class="content">
					{{ title }}
				</view>
			</block>
		</cu-custom>
	</view>
</template>

<script>
export default {
	name: 'topNavbar',
	props: {
		bgColor: {
			type: String,
			default: 'transparent'
		},
		title: {
			type: String,
			default: ''
		},
		trans: {
			type: Boolean,
			default: false
		}
	},
	data() {
		return {
			show: false,
			isWindow: false, //是否是电脑打开小程序
			bgColors: this.bgColor
		};
	},
	created() {
		wx.getSystemInfo({
			success: (res) => {
				// windows | mac为pc端
				// android | ios为手机端
				if (res.platform == 'windows' || res.platform == 'mac') {
					this.isWindow = true;
					console.log(this.isWindow);
					uni.setNavigationBarColor({
						frontColor: '#000000',
						backgroundColor: '#ffffff',
						animation: {
							duration: 400,
							timingFunc: 'easeIn'
						}
					});
				}
				console.log('getSystemInfo,', res.platform);
			}
		});
	},
	mounted() {
		let that = this;
		uni.$on('onPageScroll', function (data) {
			that.handleScroll(data);
		});
	},

	methods: {
		handleScroll(data) {
			const scrollTop = data;
			if (scrollTop > 30) {
				this.bgColors = 'bg-white'; // 背景色变为白色
			} else {
				this.bgColors = 'transparent'; // 背景色恢复透明
			}
		},
		back() {
			if (getCurrentPages().length < 2 && ' undefined' !== typeof __wxConfig) {
				let url = '/' + __wxConfig.pages[0];
				// return
				uni.redirectTo({ url });
			}
			uni.navigateBack({ delta: 1 });
		},
		goTo(item) {
			this.show = false;

			let url = '';
			switch (item) {
				case 'home':
					url = '/pages/index/index';
					uni.reLaunch({ url });
					break;
				case 'video':
					url = '/pages/video/index';
					uni.navigateTo({ url });
					break;
				default:
					url = `/pages/index/index?cur=${item}`;
					uni.reLaunch({ url });
			}
		}
	}
};
</script>

<style lang="scss">
.transp {
	background-color: rgba(0, 0, 0, 0.2);
}
.content {
	width: 320rpx;
	overflow: hidden;
}
</style>