# 组件的公共属性和事件

每个组件都有属性和事件。有些属性和事件，是所有组件都支持的。

## 组件公共属性

- id
- ref
- style
- class
- data-

<!-- CUSTOMTYPEJSON.general-attribute.example -->

## 组件公共事件

- @touchstart
- @touchmove
- @touchend
- @touchcancel
- @tap
- @click //与tap等价
- @longpress
- @transitionend

在多点触摸的屏幕上，touch事件返回数组，包含了每个touch点对应的x、y坐标。

### transition 事件

- @transitionend

	transition 效果结束时触发

	#### 兼容性

	安卓 3.93+ 版本开始支持

```vue
<template>
  <image class="transition-transform" id="transition-transform" @transitionend="onEnd" src="/static/uni.png"></image>
</template>
<script>
  export default {
    data() {
      return {}
    },
    onReady() {
      var element = uni.getElementById('transition-transform')
      element!.style.setProperty('transform', 'rotate(360deg)')
    },
    methods: {
      onEnd() {
        console.log("transition效果结束")
      }
    }
  }
</script>

<style>
  .transition-transform {
    transition-duration: 2000;
    transition-property: transform;
    transform: rotate(0deg);
  }
</style>
```

### 冒泡事件系统

DOM事件主要有三个阶段：捕获阶段、目标阶段和冒泡阶段。

以点击事件为例，当触发点击时，
1. 首先从根节点逐级向下分发，直到监听点击事件的节点为止（捕获阶段）；
2. 然后事件到达当前节点并触发点击事件（目标阶段）；
3. 接着继续向上逐级触发父节点的点击事件，直到根节点为止（冒泡阶段）。

注意，虽然有3个阶段，但第2个阶段（“目标阶段”：事件到达了元素）并没有单独处理：捕获和冒泡阶段的处理程序都会在该阶段触发。

我们一般使用默认的事件注册机制，将事件注册到冒泡阶段，相对来说，大多数处理情况都在冒泡阶段。

uvue 目前暂不支持事件的捕获阶段。

#### 阻止冒泡

在事件回调中，可以通过调用`event.stopPropagation`方法阻止事件冒泡。

```ts
handleClick (event : MouseEvent) {
    // 阻止继续冒泡.
    event.stopPropagation();
}
```

#### 阻止默认行为

在事件回调中，可以通过调用`event.preventDefault`方法阻止默认行为。`event.preventDefault`仅处理默认行为，事件冒泡不会被阻止。

```vue
<template>
	<scroll-view style="flex: 1;">
		<view style="width: 750rpx;height: 1750rpx;background-color: bisque;">
			滑动框中区域修改进度并阻止滚动，滑动其余空白区域触发滚动
			<view style="width: 750rpx;height: 40rpx; margin-top: 100rpx;border:5rpx;" @touchmove="slider">
				<view ref="view1" style="background-color: chocolate;width: 0rpx;height: 30rpx;"></view>
			</view>
		</view>
	</scroll-view>
</template>
<script>
	export default {
		data() {
			return {
				$view1Element: null as UniElement | null
			}
		},
    onReady() {
      this.$view1Element = this.$refs['view1'] as UniElement
    },
		methods: {
			slider(e : TouchEvent) {
				e.preventDefault() // 阻止外层scroll-view滚动行为
				this.$view1Element!.style?.setProperty('width', e.touches[0].screenX);
			}
		}
	}
</script>
```

### Bug & Tips

连续触发`click`或`tap`事件，可能会出现事件丢失的情况。

## Event

<!-- CUSTOMTYPEJSON.Event.description -->

<!-- CUSTOMTYPEJSON.Event.extends -->

<!-- CUSTOMTYPEJSON.Event.param -->



### Event 方法 @event-methods
<!-- CUSTOMTYPEJSON.Event.methods.stopPropagation.name -->

<!-- CUSTOMTYPEJSON.Event.methods.stopPropagation.description -->

<!-- CUSTOMTYPEJSON.Event.methods.stopPropagation.param -->

<!-- CUSTOMTYPEJSON.Event.methods.stopPropagation.returnValue -->

<!-- CUSTOMTYPEJSON.Event.methods.stopPropagation.compatibility -->

<!-- CUSTOMTYPEJSON.Event.methods.stopPropagation.tutorial -->

<!-- CUSTOMTYPEJSON.Event.methods.preventDefault.name -->

<!-- CUSTOMTYPEJSON.Event.methods.preventDefault.description -->

<!-- CUSTOMTYPEJSON.Event.methods.preventDefault.param -->

<!-- CUSTOMTYPEJSON.Event.methods.preventDefault.returnValue -->

<!-- CUSTOMTYPEJSON.Event.methods.preventDefault.compatibility -->

<!-- CUSTOMTYPEJSON.Event.methods.preventDefault.tutorial -->

## CustomEvent

<!-- CUSTOMTYPEJSON.CustomEvent.description -->

<!-- CUSTOMTYPEJSON.CustomEvent.extends -->

<!-- CUSTOMTYPEJSON.CustomEvent.param -->



### CustomEvent 方法 @customevent-methods
<!-- CUSTOMTYPEJSON.CustomEvent.methods.stopPropagation.name -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.stopPropagation.description -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.stopPropagation.param -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.stopPropagation.returnValue -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.stopPropagation.compatibility -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.stopPropagation.tutorial -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.preventDefault.name -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.preventDefault.description -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.preventDefault.param -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.preventDefault.returnValue -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.preventDefault.compatibility -->

<!-- CUSTOMTYPEJSON.CustomEvent.methods.preventDefault.tutorial -->

## CustomEventOptions

<!-- CUSTOMTYPEJSON.CustomEventOptions.description -->

<!-- CUSTOMTYPEJSON.CustomEventOptions.extends -->

<!-- CUSTOMTYPEJSON.CustomEventOptions.param -->

## MouseEvent

<!-- CUSTOMTYPEJSON.MouseEvent.description -->

<!-- CUSTOMTYPEJSON.MouseEvent.extends -->

<!-- CUSTOMTYPEJSON.MouseEvent.param -->


### MouseEvent 方法 @mouseevent-methods
<!-- CUSTOMTYPEJSON.MouseEvent.methods.stopPropagation.name -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.stopPropagation.description -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.stopPropagation.param -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.stopPropagation.returnValue -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.stopPropagation.compatibility -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.stopPropagation.tutorial -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.preventDefault.name -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.preventDefault.description -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.preventDefault.param -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.preventDefault.returnValue -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.preventDefault.compatibility -->

<!-- CUSTOMTYPEJSON.MouseEvent.methods.preventDefault.tutorial -->

## TouchEvent

<!-- CUSTOMTYPEJSON.TouchEvent.description -->

<!-- CUSTOMTYPEJSON.TouchEvent.extends -->

<!-- CUSTOMTYPEJSON.TouchEvent.param -->

### TouchEvent 方法 @touchevent-methods
<!-- CUSTOMTYPEJSON.TouchEvent.methods.stopPropagation.name -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.stopPropagation.description -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.stopPropagation.param -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.stopPropagation.returnValue -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.stopPropagation.compatibility -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.stopPropagation.tutorial -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.preventDefault.name -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.preventDefault.description -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.preventDefault.param -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.preventDefault.returnValue -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.preventDefault.compatibility -->

<!-- CUSTOMTYPEJSON.TouchEvent.methods.preventDefault.tutorial -->

## Touch

<!-- CUSTOMTYPEJSON.Touch.description -->

<!-- CUSTOMTYPEJSON.Touch.extends -->

<!-- CUSTOMTYPEJSON.Touch.param -->

<!-- CUSTOMTYPEJSON.general-event.example -->

## 参见

- [相关 Bug](https://issues.dcloud.net.cn/?mid=component.common)