如何使用SwiftUI使按钮可拖动/移动?
我正在尝试使一个按钮可以用SwiftUI移动。从表面上看,这应该是可行的。我曾尝试将带有文本的按钮放在另一个ZStack中,有一秒钟它工作正常,但我一松开按钮,拖动就停止了,我无法再拖动了。我注意到,尽管按钮移动了,但水龙头仍保持在中间。而且拖拉的车看起来像是四轮马车如何使用SwiftUI使按钮可拖动/移动?,swift,xcode,swift5.2,swiftui,Swift,Xcode,Swift5.2,Swiftui,我正在尝试使一个按钮可以用SwiftUI移动。从表面上看,这应该是可行的。我曾尝试将带有文本的按钮放在另一个ZStack中,有一秒钟它工作正常,但我一松开按钮,拖动就停止了,我无法再拖动了。我注意到,尽管按钮移动了,但水龙头仍保持在中间。而且拖拉的车看起来像是四轮马车 struct CircleButton: View { @State private var dragAmount = CGSize.zero var body: some View { ZStack {
struct CircleButton: View {
@State private var dragAmount = CGSize.zero
var body: some View {
ZStack {
Button(action: performAction){
ZStack {
Circle()
.foregroundColor(.blue)
.frame(width: 100, height: 100)
Text("Move me")
.foregroundColor(.white)
.font(.system(.caption, design: .serif))
}
}
.animation(.default)
.offset(self.dragAmount)
}
.gesture(
DragGesture()
.onChanged { self.dragAmount = $0.translation})
}
func performAction(){
print("button pressed")
}
}
我试过这个:
struct CircleButton: View {
@State private var dragAmount = CGSize.zero
var body: some View {
ZStack {
ZStack {
Button(action: performAction){
Circle()
.foregroundColor(.blue)
.frame(width: 100, height: 100)
}
Text("Tap me")
}
.offset(self.dragAmount)
.animation(.default)
}
.gesture(
DragGesture()
.onChanged{ self.dragAmount = $0.translation})
}
func performAction(){
print("button pressed")
}
}
下面是一个可能方法的演示。使用Xcode 11.4/iOS 13.4进行测试和工作 另请参见注释内联
struct CircleButton: View {
@State private var dragAmount: CGPoint?
var body: some View {
GeometryReader { gp in // just to center initial position
ZStack {
Button(action: self.performAction) {
ZStack {
Circle()
.foregroundColor(.blue)
.frame(width: 100, height: 100)
Text("Move me")
.foregroundColor(.white)
.font(.system(.caption, design: .serif))
}
}
.animation(.default)
.position(self.dragAmount ?? CGPoint(x: gp.size.width / 2, y: gp.size.height / 2))
.highPriorityGesture( // << to do no action on drag !!
DragGesture()
.onChanged { self.dragAmount = $0.location})
}
.frame(maxWidth: .infinity, maxHeight: .infinity) // full space
}
}
func performAction() {
print("button pressed")
}
}
struct CircleButton:视图{
@国家私有var dragAmount:CGPoint?
var body:一些观点{
GeometryReader{gp in//刚好到中心初始位置
ZStack{
按钮(动作:自我执行){
ZStack{
圈()
.foregroundColor(.blue)
.框架(宽度:100,高度:100)
文本(“移动我”)
.foregroundColor(.白色)
.font(.system(.caption,design:.serif))
}
}
.animation(.default)
.位置(自dragAmount??CGPoint(x:gp.size.width/2,y:gp.size.height/2))
.highprioritysignature(//做些不同的简洁的事情怎么样:
import SwiftUI
struct ContentView: View {
var body: some View {
CircleButton()
}
}
struct CircleButton: View {
@State private var pos = CGPoint(x:222,y:222) // just for testing
var body: some View {
theButton.position(self.pos).highPriorityGesture(self.drag)
}
var theButton: some View {
ZStack {
Circle()
.foregroundColor(.blue)
.frame(width: 100, height: 100)
.onTapGesture { self.performAction() }
Text("Tap me")
.foregroundColor(.white)
.font(.system(.caption, design: .serif))
}
}
func performAction(){
print("button pressed")
}
var drag: some Gesture {
DragGesture().onChanged { value in self.pos = CGPoint(x: value.location.x, y: value.location.y)}
}
}
我在这里找到了一个简单的解决方案。只需一个ViewModifier和一个扩展:
struct DraggablePita: View {
var body: some View {
Image(uiImage: UIImage(named: "pita.png")!)
.draggable() // Add the new, custom modifier to make this draggable
}
}
// Handle dragging
struct DraggableView: ViewModifier {
@State var offset = CGPoint(x: 0, y: 0)
func body(content: Content) -> some View {
content
.gesture(DragGesture(minimumDistance: 0)
.onChanged { value in
self.offset.x += value.location.x - value.startLocation.x
self.offset.y += value.location.y - value.startLocation.y
})
.offset(x: offset.x, y: offset.y)
}
}
// Wrap `draggable()` in a View extension to have a clean call site
extension View {
func draggable() -> some View {
return modifier(DraggableView())
}
}
一个问题:当我删除.frame()时你在底部添加的方法,我注意到结果是一样的。是否有必要使用它的原因?我看到它旁边的注释写满了空格,但我不确定它的意思。@OcielLerma,它仍然是最初尝试时使用的,没有使用GeometryReader,因此如果要删除它,应该是这样的。但是如果你保持它不变,t当您可以安全地删除.frame修改器时,请使用.animation(.none)
停止拖动