SwiftUI |使用onDrag和onDrop对单个LazyGrid中的项目重新排序? [英] SwiftUI | Using onDrag and onDrop to reorder Items within one single LazyGrid?
问题描述
我想知道是否可以使用 View.onDrag
和 View.onDrop
添加拖动和
尽管我能够使用 onDrag拖动每个项目,但是否可以在一个
LazyGrid
中手动重新排序?
code>,我不知道如何实现删除部分。
这是我正在尝试的代码:
import SwiftUI
/ / MARK:-数据
结构数据:可识别的{
let id:Int
}
// MARK:-模型
类模型:ObservableObject {
@已发布的var数据:[数据]
让列= [
GridItem(.fixed(160)),
GridItem (.fixed(160))
]
init(){
data = Array< Data>(重复:Data(id:0),计数:100)
for i in 0 ..< data.count {
data [i] = Data(id:i)
}
}
}
// MARK:-网格
struct ContentView:View {
@StateObject private var model = Model()
var正文:某些视图{
ScrollView {
LazyVGrid(列:model.columns,间距:32){
ForEach(model.data){d在
ItemView(d :d)
.id(d.id)
.frame(宽度:160,高度:240)
.background(Color.green)
.onDrag {return NSItemProvider(对象:String(d.id)as NSString)}
}
}
}
}
}
// MARK:- GridItem
struct ItemView:View {
var d:Data
var body:some View {
VStack {
Text(String( d.id))
.font(.headline)
.foregroundColor(.white)
}
}
}
SwiftUI 2.0
完成了可能方法的简单演示(没有进行太多调整,因为代码像演示一样快速增长)。
重要的一点是:a)重新排序不假定等待下降,因此应实时跟踪; b)为避免与坐标共舞,处理逐格项目视图更简单; c)找到要移动的内容并在数据模型中执行此操作,以便SwiftUI自己对视图进行动画处理。
通过Xcode 12b3 / iOS 14测试
导入SwiftUI
导入UniformTypeIdentifiers
struct GridData:可识别的,相等的{
let id:Int
}
// MARK:-模型
类模型:ObservableObject {
@已发布的var数据:[GridData]
让列= [
GridItem(.fixed(160)),
GridItem(.fixed(160))
]
init(){
data = Array(重复:GridData( id:0),count:100)
for i in 0 ..< data.count {
data [i] = GridData(id:i)
}
}
}
//标记:-网格
结构DemoDragRelocateView:视图{
@StateObject private var model = Model()
@State private var dragging:GridData?
var主体:某些视图{
ScrollView {
LazyVGrid(列:model.columns,间距:32){
ForEach(model.data){d
GridItemView(d:d)
.overlay(dragging?.id == d.id?Color.white.opacity(0.8):Color.clear)
.onDrag {
self.dragging = d
返回NSItemProvider(object:String(d.id)as NSString)
}
.onDrop(of:[UTType.text],委托:DragRelocateDelegate(item: d,listData:$ model.data,当前:$ dragging))
}
} .animation(.default,value:model.data)
}
}
}
结构DragRelocateDelegate:DropDelegate {
let项:GridData
@Binding var listData:[GridData]
@Binding var当前:GridData?
func dropEntered(info:DropInfo){
如果item!= current {
let from = listData.firstIndex(of:current!)!
让我们= listData.firstIndex(of:item)!
if listData [to] .id!= current!.id {
listData.move(fromOffsets:IndexSet(integer:from),
toOffset:to> from?to + 1: to)
}
}
}
func dropUpdated(info:DropInfo)-> DropProposal? {
return DropProposal(operation:.move)
}
func performDrop(info:DropInfo)-> Bool {
self.current = nil
return true
}
}
// MARK:-GridItem
结构GridItemView:View {
var d:GridData
var body:some View {
VStack {
Text(String(d.id))
。 font(.headline)
.foreColorColor(.white)
}
.frame(宽度:160,高度:240)
.background(Color.green)
}
}
I was wondering if it is possible to use the View.onDrag
and View.onDrop
to add drag and drop reordering within one LazyGrid
manually?
Though I was able to make every Item draggable using onDrag
, I have no idea how to implement the dropping part.
Here is the code I was experimenting with:
import SwiftUI
//MARK: - Data
struct Data: Identifiable {
let id: Int
}
//MARK: - Model
class Model: ObservableObject {
@Published var data: [Data]
let columns = [
GridItem(.fixed(160)),
GridItem(.fixed(160))
]
init() {
data = Array<Data>(repeating: Data(id: 0), count: 100)
for i in 0..<data.count {
data[i] = Data(id: i)
}
}
}
//MARK: - Grid
struct ContentView: View {
@StateObject private var model = Model()
var body: some View {
ScrollView {
LazyVGrid(columns: model.columns, spacing: 32) {
ForEach(model.data) { d in
ItemView(d: d)
.id(d.id)
.frame(width: 160, height: 240)
.background(Color.green)
.onDrag { return NSItemProvider(object: String(d.id) as NSString) }
}
}
}
}
}
//MARK: - GridItem
struct ItemView: View {
var d: Data
var body: some View {
VStack {
Text(String(d.id))
.font(.headline)
.foregroundColor(.white)
}
}
}
Thank you!
SwiftUI 2.0
Here is completed simple demo of possible approach (did not tune it much, `cause code growing fast as for demo).
Important points are: a) reordering does not suppose waiting for drop, so should be tracked on the fly; b) to avoid dances with coordinates it is more simple to handle drop by grid item views; c) find what to where move and do this in data model, so SwiftUI animate views by itself.
Tested with Xcode 12b3 / iOS 14
import SwiftUI
import UniformTypeIdentifiers
struct GridData: Identifiable, Equatable {
let id: Int
}
//MARK: - Model
class Model: ObservableObject {
@Published var data: [GridData]
let columns = [
GridItem(.fixed(160)),
GridItem(.fixed(160))
]
init() {
data = Array(repeating: GridData(id: 0), count: 100)
for i in 0..<data.count {
data[i] = GridData(id: i)
}
}
}
//MARK: - Grid
struct DemoDragRelocateView: View {
@StateObject private var model = Model()
@State private var dragging: GridData?
var body: some View {
ScrollView {
LazyVGrid(columns: model.columns, spacing: 32) {
ForEach(model.data) { d in
GridItemView(d: d)
.overlay(dragging?.id == d.id ? Color.white.opacity(0.8) : Color.clear)
.onDrag {
self.dragging = d
return NSItemProvider(object: String(d.id) as NSString)
}
.onDrop(of: [UTType.text], delegate: DragRelocateDelegate(item: d, listData: $model.data, current: $dragging))
}
}.animation(.default, value: model.data)
}
}
}
struct DragRelocateDelegate: DropDelegate {
let item: GridData
@Binding var listData: [GridData]
@Binding var current: GridData?
func dropEntered(info: DropInfo) {
if item != current {
let from = listData.firstIndex(of: current!)!
let to = listData.firstIndex(of: item)!
if listData[to].id != current!.id {
listData.move(fromOffsets: IndexSet(integer: from),
toOffset: to > from ? to + 1 : to)
}
}
}
func dropUpdated(info: DropInfo) -> DropProposal? {
return DropProposal(operation: .move)
}
func performDrop(info: DropInfo) -> Bool {
self.current = nil
return true
}
}
//MARK: - GridItem
struct GridItemView: View {
var d: GridData
var body: some View {
VStack {
Text(String(d.id))
.font(.headline)
.foregroundColor(.white)
}
.frame(width: 160, height: 240)
.background(Color.green)
}
}
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