【每日学点HarmonyOS Next知识】图片拖动、动画放大、列表高度、返回键监听、分割线颜色
1、HarmonyOS image 组件的图片可以随意拖动?
mage组件默认拖拽效果,draggable设置为true时,组件可拖拽,参考以下文档:https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/image-V5
HarmonyOS中Image组件默认支持长按触发拖拽事件。具体来说,Image组件的拖拽能力是通过设置组件的draggable属性来实现的。通常情况下,Text、TextInput、TextArea、Hyperlink、Image和RichEditor组件的draggable属性是默认为true的,这意味着这些组件可以被长按并拖拽。可以通过自定义image相关组件,实现部分把draggable关了
2、HarmonyOS 换成model后动画放大实现不了?
listitem内容为object,不能直接用 ==
判断当前item,可以改用index确定当前点击的item,修改如下:(其他案例参考:https://gitee.com/harmonyos-cases/cases/tree/master/CommonAppDevelopment/feature/listexchange)
import curves from '@ohos.curves';
@Entry
@Component
struct model {
@State private arr: titleStrModel[] = []
@State dragItem: titleStrModel = new titleStrModel()
@State scaleItem: titleStrModel = new titleStrModel()
@State neighborItem: titleStrModel = new titleStrModel()
@State selectedIndex:number = -1
@State neighborScale: number = -1
private dragRefOffset: number = 0
@State offsetX: number = 0
@State offsetY: number = 0
private ITEM_INTV: number = 120
aboutToAppear(): void {
const d = new titleStrModel()
d.name = 'wewewe'
const b = new titleStrModel()
b.name = 'adadad'
const h = new titleStrModel()
h.name = 'dfdfdf'
this.arr.push(d)
this.arr.push(b)
this.arr.push(h)
}
//根据当前index确定item是否缩放
scaleSelect(item: titleStrModel):void {
this.selectedIndex = this.arr.indexOf(item)
this.arr[this.selectedIndex].scale = 1.05
}
itemMove(index: number, newIndex: number): void {
let tmp = this.arr.splice(index, 1)
this.arr.splice(newIndex, 0, tmp[0])
}
build() {
Stack() {
List({ space: 20, initialIndex: 0 }) {
ForEach(this.arr, (item: titleStrModel) => {
ListItem() {
Row() {
Text('' + item.name)
.width('100%')
.height(100)
.fontSize(16)
.textAlign(TextAlign.Center)
.borderRadius(10)
.backgroundColor(0xFFFFFF)
Image($r('app.media.app_icon'))
.width(100)
.height(100)
}
.shadow(this.scaleItem.name == item.name ? { radius: 70, color:Color.Blue, offsetX: 0, offsetY: 0 } :
{ radius: 0, color: Color.Blue, offsetX: 0, offsetY: 0 })
.animation({ curve: Curve.Sharp, duration: 300 })
}
.margin({ left: 12, right: 12 })
.scale({ x: item.scale, y: item.scale })
.zIndex(this.dragItem.name == item.name ? 1 : 0)
.translate(this.dragItem.name == item.name ? { y: this.offsetY } : { y: 0 })
.gesture(
//以下组合手势为顺序识别,当长按手势事件未正常触发时则不会触发拖动手势事件
GestureGroup(GestureMode.Sequence,
LongPressGesture({ repeat: true })
.onAction((event?: GestureEvent) => {
animateTo({ curve: Curve.Friction, duration: 300 }, () => {
this.scaleItem = item
this.scaleSelect(item)
})
})
.onActionEnd(() => {
animateTo({ curve: Curve.Friction, duration: 300 }, () => {
this.scaleItem = new titleStrModel()
})
}),
PanGesture({ fingers: 1, direction: null, distance: 0 })
.onActionStart(() => {
this.dragItem = item
this.dragRefOffset = 0
})
.onActionUpdate((event: GestureEvent) => {
this.offsetY = event.offsetY - this.dragRefOffset
// console.log('Y:' + this.offsetY.toString())
this.neighborItem = new titleStrModel()
let index = this.arr.indexOf(item)
let curveValue = curves.initCurve(Curve.Sharp)
let value: number = 0
//根据位移计算相邻项的缩放
if (this.offsetY < 0) {
value = curveValue.interpolate(-this.offsetY / this.ITEM_INTV)
this.neighborItem = this.arr[index-1]
this.neighborScale = 1 - value / 20;
console.log('neighborScale:' + this.neighborScale.toString())
} else if (this.offsetY > 0) {
value = curveValue.interpolate(this.offsetY / this.ITEM_INTV)
this.neighborItem = this.arr[index+1]
this.neighborScale = 1 - value / 20;
}
//根据位移交换排序
if (this.offsetY > this.ITEM_INTV / 2) {
animateTo({ curve: curves.interpolatingSpring(0, 1, 400, 38) }, () => {
this.offsetY -= this.ITEM_INTV
this.dragRefOffset += this.ITEM_INTV
this.itemMove(index, index + 1)
})
} else if (this.offsetY < -this.ITEM_INTV / 2) {
animateTo({ curve: curves.interpolatingSpring(0, 1, 400, 38) }, () => {
this.offsetY += this.ITEM_INTV
this.dragRefOffset -= this.ITEM_INTV
this.itemMove(index, index - 1)
})
}
})
.onActionEnd((event: GestureEvent) => {
animateTo({ curve: curves.interpolatingSpring(0, 1, 400, 38) }, () => {
this.dragItem = new titleStrModel()
this.neighborItem = new titleStrModel()
//动画结束将缩放还原
this.arr[this.arr.indexOf(this.scaleItem)].scale = 1
})
animateTo({
curve: curves.interpolatingSpring(14, 1, 170, 17), delay: 150
}, () => {
this.scaleItem = new titleStrModel()
})
})
)
.onCancel(() => {
animateTo({ curve: curves.interpolatingSpring(0, 1, 400, 38) }, () => {
this.dragItem = new titleStrModel()
this.neighborItem = new titleStrModel()
})
animateTo({
curve: curves.interpolatingSpring(14, 1, 170, 17), delay: 150
}, () => {
this.scaleItem = new titleStrModel()
})
})
)
})
}
}.width('100%').height('100%').backgroundColor(0xDCDCDC).padding({ top: 5 })
}
}
class titleStrModel {
name:string = ''
scale:number = 1 //增加scale属性, 每个item都有对应的scale值
}
3、HarmonyOS 为什么List的高度设置100% 还是显示不全?
问题是解决了(方法:子控件Column,List都加上layoutWeight(1)),有点疑惑,想请教一下:
- 为什么外部用了layoutWeight(1) 内部所有的Column与List也要用layoutWeight(1) 想知道原理
- 外部我已经计算高度了(TNAppUIData.getPageHeight())为什么Tabs我不用layoutWeight(1)还是占满屏幕的剩余高度,我计算给的高度不起作用?
问题1:父容器尺寸确定时,设置了layoutWeight属性的子元素与兄弟元素占主轴尺寸按照权重进行分配,前提是父容器尺寸确定。比如共有三个元素且都用了layoutWeight(1),它们按照“1:1:1”的比例均分父容器主轴方向的空间。与.width(‘33%’)、.width(‘34%’)、.width(‘33%’)效果相同。
问题2:tabs是默认占满屏幕的
4、HarmonyOS 物理返回键监听?
customdialog弹窗打开时,按物理返回键,希望不关闭弹窗
可以使用onBackPress当用户点击返回按钮时触发,仅@Entry装饰的自定义组件生效。返回true表示页面自己处理返回逻辑,不进行页面路由;返回false表示使用默认的路由返回逻辑,不设置返回值按照false处理。参考文档:https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/ts-custom-component-lifecycle-V5#onbackpress
onBackPress?(): void | boolean
当用户点击返回按钮时触发,仅@Entry装饰的自定义组件生效。返回true表示页面自己处理返回逻辑,不进行页面路由;返回false表示使用默认的路由返回逻辑,不设置返回值按照false处理。
// xxx.ets
@Entry
@Component
struct IndexComponent {
@State textColor: Color = Color.Black;
onPageShow() {
this.textColor = Color.Blue;
console.info('IndexComponent onPageShow');
}
onPageHide() {
this.textColor = Color.Transparent;
console.info('IndexComponent onPageHide');
}
onBackPress() {
this.textColor = Color.Red;
console.info('IndexComponent onBackPress');
}
build() {
Column() {
Text('Hello World')
.fontColor(this.textColor)
.fontSize(30)
.margin(30)
}.width('100%')
}
}
5、HarmonyOS list divider中startmargin前面的颜色怎么和listitem保持一致?
目前使用list的divider属性并不能满足你想实现的效果,可以自定义实现分隔线效果,参考如下代码:
build() {
Row(){
List(){
ListItem(){
Flex({direction:FlexDirection.Column,justifyContent:FlexAlign.SpaceBetween}){
Text('test')
Divider()
.color(Color.Red)
// .height(15)
.strokeWidth(5)
.margin({left:50})
}
}.backgroundColor(Color.Blue)
.height(100)
ListItem(){
Flex({direction:FlexDirection.Column,justifyContent:FlexAlign.SpaceBetween}){
Text('test')
Divider()
.color(Color.Red)
.strokeWidth(5)
.margin({left:50,bottom:0})
}
}.backgroundColor(Color.Orange)
.height(100)
ListItem(){
Flex({direction:FlexDirection.Column,justifyContent:FlexAlign.SpaceBetween}){
Text('test')
Divider()
.color(Color.Red)
.strokeWidth(5)
.margin({left:50})
}
}.backgroundColor(Color.Yellow)
.height(100)
}
// .divider({strokeWidth:5,color:Color.Red,startMargin:50})
.width('100%').height('100%')
.backgroundColor(Color.Gray)
}
}