最近来个需求，要求给小程序的 modal 增加个关闭按钮，上网一查发现原来 2018 年就有人给出解决方案了，于是总结下微信小程序自定义组件的思路：一句话，用 wxml + css实现和原生组件类似的样式和效果，之后用 JS 实现类似原生组件的功能。
比如 modal 组件，观察可以得出就是个在页面顶层显示的 mask + div。modal 的显示与否可以通过 wx-if 控制，需要注意的点是 modal 显示的时候要有动画效果，这个功能可以通过 css animation 实现。
自定义 modal 的示例代码：
WXML:
<view wx-if="{{cusModalShow}}" bindtap="handleCusModalMaskTap" class="cus-modal"><view catchtap class="cus-modal__content"><view class="cus-modal__close-btn" bindtap="handleCusModalMaskTap">×</view><view class="cus-modal__content-title"><text>提示</text></view><view class="cus-modal__content-text"><text>请确认操作</text></view><view class="cus-modal__content-buttons"><text bindtap="handleCusModalCancel" class="cus-modal__content-button-cancel">取消</text><text bindtap="handleCusModalConfirm" class="cus-modal__content-button-confirm">确认</text></view></view>
</view>
CSS:
@keyframes fade-in {0% {opacity: 0;}100% {opacity: 1;}
}.cus-modal {display: flex;align-items: center;justify-content: center;position: fixed;top: 0;left: 0;width: 100%;height: 100%;background: rgba(0, 0, 0, 0.6);animation: fade-in 0.3s ease;
}.cus-modal__content {background-color: white;border-radius: 15px;width: 80%;position: relative;
}.cus-modal__close-btn {color: rgb(179, 179, 179);font-size: 1.5rem;position: absolute;right: 0.5rem;top: 0.1rem;
}.cus-modal__content-title,
.cus-modal__content-text {font-size: 1.1rem;text-align: center;
}.cus-modal__content-title {font-weight: bold;margin: 40px 0 20px 0;
}.cus-modal__content-text {color: rgb(179, 179, 179);margin-bottom: 40px;
}.cus-modal__content-buttons {display: flex;
}.cus-modal__content-buttons {border-top: 1px solid rgb(245, 245, 245);
}.cus-modal__content-buttons>text {flex: 1;text-align: center;padding: 20px 30px;border-right: 1px solid rgb(245, 245, 245);box-sizing: border-box;height: 60px;
}.cus-modal__content-buttons>text:last-child {border-right: none;
}.cus-modal__content-button-cancel {font-weight: bold;
}.cus-modal__content-button-confirm {font-weight: bold;color: rgb(90, 117, 155);
}
自定义 Picker：
这里实际只是模拟了原生 Picker 从底部弹入的效果，具体内容可以通过放在里面的组件实现。
WXML
<view bindtap="closeBottomPicker" wx-if="{{cusPickerShow}}" class="cus-picker"><view class="cus-picker__mask"></view><view catchtap class="cus-picker__content"><!-- <view class="cus-picker__header"><text class="cus-pick__header__btn-cancel">取消</text><text class="cus-pick__header__btn-confirm">确定</text></view> --><some-component bindclose="handleCarFilterClose"></some-component></view>
</view>
CSS:
@keyframes slide-up-from-bottom {0% {transform: translateY(100%);}100% {transform: translateY(0);}
}@keyframes fade-in {0% {opacity: 0;}100% {opacity: 1;}
}.cus-picker {z-index: 114514;position: fixed;top: 0;left: 0;width: 100%;height: 100%;
}.cus-picker__mask {position: absolute;width: 100%;height: 100%;left: 0;top: 0;background-color: rgba(0, 0, 0, 0.5);animation: fade-in 0.3s ease;
}.cus-picker__content {box-sizing: border-box;position: absolute;height: 50%;width: 100%;bottom: 0;background-color: white;animation: slide-up-from-bottom 0.3s ease;
}.cus-picker__header {display: flex;justify-content: space-between;padding: 20px;border-bottom: 1px solid rgb(245, 245, 245);font-size: 16px;
}.cus-pick__header__btn-cancel {color: rgb(127, 127, 127);
}.cus-pick__header__btn-confirm {color: rgb(0, 196, 105);
}
