Releases: josercc/DeveloperGist
Releases · josercc/DeveloperGist
2022年开发笔记第一期
解决 Dart 打印日志打印不全
我们测试了[print] [debugPrint] [log] 三个函数
分别打印 10000行的日志
- 【print】函数打印几百个字符就停止打印
- 【debugPrint】虽然可以打印完毕 但是耗时 40秒
- 【log】瞬间打印完毕
请使用【log】函数打印日志
修复 Center 组件宽度被拉长
40，左右的Padding分别为40。
TextButton(
onPressed: () {},
child: Container(
height: 40,
decoration: BoxDecoration(
color: Colors.green,
borderRadius: BorderRadius.circular(4),
),
child: const Center(
child: Padding(
padding: EdgeInsets.symmetric(horizontal: 40),
child: Text(
"登录",
style: TextStyle(
color: Colors.white,
),
),
),
),
),
)
结果按钮宽度被拉伸了。了解可以通过Center.widthFactor属性进行设置。
如果非空，则将其宽度设置为子宽度乘以该因子。
可以大于也可以小于 1.0，但必须为非负数。
TextButton(
onPressed: () {},
child: Container(
height: 40,
decoration: BoxDecoration(
color: Colors.green,
borderRadius: BorderRadius.circular(4),
),
child: const Center(
widthFactor: 1,
child: Padding(
padding: EdgeInsets.symmetric(horizontal: 40),
child: Text(
"登录",
style: TextStyle(
color: Colors.white,
),
),
),
),
),
)我们设置1 ,代表等于child的宽度。
修复 Column 自动拉伸。
在做这个效果过程中。
Container(
constraints: const BoxConstraints(
minHeight: 90,
minWidth: 90,
),
decoration: BoxDecoration(
color: Colors.black,
borderRadius: BorderRadius.circular(4),
),
padding: const EdgeInsets.all(15),
child: Column(
children: const [
CircularProgressIndicator(
color: Colors.white,
strokeWidth: 2,
),
SizedBox(
height: 15,
),
Text(
"加载中",
style: TextStyle(color: Colors.white),
),
],
),
)
但是我们的组件纵向铺满了，这不是我们要的效果呀。
MainAxisSize mainAxisSize = MainAxisSize.max,查询到Column有mainAxisSize属性默认为MainAxisSize.max,那我们设置MainAxisSize.min是不是就可以了呀。
Container(
constraints: const BoxConstraints(
minHeight: 90,
minWidth: 90,
),
decoration: BoxDecoration(
color: Colors.black,
borderRadius: BorderRadius.circular(4),
),
padding: const EdgeInsets.all(15),
child: Column(
mainAxisSize: MainAxisSize.min,
children: const [
CircularProgressIndicator(
color: Colors.white,
strokeWidth: 2,
),
SizedBox(
height: 15,
),
Text(
"加载中",
style: TextStyle(color: Colors.white),
),
],
),
)
showMaterialModalBottomSheet 不支持 Hot Reload
将 showMaterialModalBottomSheet builder内容单独提炼一个Widget即可
Flutter 怎么去掉 AppBar 底部阴影
设置 elevation = 0 即可
2021年开发笔记第一期
iOS13之后怎么获取Key Window
static var keyWindow:UIWindow? {
if #available(iOS 13.0, *) {
return UIApplication.shared.connectedScenes
.filter({$0.activationState == .foregroundActive})
.compactMap({$0 as? UIWindowScene})
.first?.windows
.filter({$0.isKeyWindow})
.first
} else {
return UIApplication.shared.windows
.filter({$0.isKeyWindow})
.first
}
}'xxx_App' is annotated with @main and must provide a main static function of type () -> Void or () throws -> Void. Inheritance from non-protocol type 'App'
谷歌了半天，很多人都遇到过，但是都不能解决我的问题，后来研究发现，我项目存在一样的App名字的Struct，带上模块名字就修复了。
@main
struct Win_App: SwiftUI.App {
...
}SwiftUI 怎么在任何 Function 中实行跳转
struct ContentView: View {
/// 控制何时进行跳转
@State var action: Bool = false
var body: some View {
NavigationView {
HStack(spacing:0) {
/// NavigationLink 返回 `EmptyView` 不污染界面
NavigationLink(destination: destination, isActive: $action) {
EmptyView()
}
Text("Click me!")
.onTapGesture {
self.clicked()
}
}
}
}
func clicked() {
/// 执行跳转
action = true
}
}隐藏返回按钮文本
let backButtonAppearance = UIBarButtonItemAppearance()
backButtonAppearance.normal.titleTextAttributes = [
.font : UIFont.systemFont(ofSize: 0),
]
appearance.backButtonAppearance = backButtonAppearance修改 SwiftUI 返回按钮的颜色
NavigationView {
...
}
.accentColor(.black)
需要注意的是官方说
accentColor已经要废弃了，Use the asset catalog's accent color or View.tint(_:) instead."但是替换为
tint不起作用。
隐藏 SwiftUI 的 UITabbar
需要在需要隐藏界面进行设置
struct PalletBindBoxNumberPage: View {
...
var body: some View {
...
.onAppear {
App.tabBar?.isHidden = true
}
.onDisappear {
App.tabBar?.isHidden = false
}
}
}struct App {
static var keyWindow:UIWindow? {
if #available(iOS 13.0, *) {
return UIApplication.shared.connectedScenes
.filter({$0.activationState == .foregroundActive})
.compactMap({$0 as? UIWindowScene})
.first?.windows
.filter({$0.isKeyWindow})
.first
} else {
return UIApplication.shared.windows
.filter({$0.isKeyWindow})
.first
}
}
static var tabBar:UITabBar? {
return keyWindow?.rootViewController
.flatMap({$0.view})
.flatMap({$0.subviews.first})
.flatMap({$0.subviews.first})
.map({$0.subviews})
.map({$0.compactMap({$0 as? UITabBar})})
.flatMap({$0.first})
}
}巧妙利用 flatMap 和 Map 进行解包
比如我有下面的一个结构
struct Model {
let age:Int?
}
let model:Model?此时我想让age显示在文本中，你可能这么写
if let age = model?.age {
Text("\(age)")
} else {
Text("")
}但是使用flatMap和map进行解包
Text(model.flatMap({$0.age}).map({"\($0)"}) ?? "")Contributors
main
Assets 2
2020年开发笔记第一期
SwiftUI中怎么设置选中图片的颜色？
public func accentColor(_ accentColor: Color?) -> some ViewExample
import SwiftUI
/// 自定义的Tab
struct CustomTabView<Content:View>: View {
///需要展示的内容元祖数组
/// - Parameter title: 显示标题
/// - Parameter image: 默认的显示图片
/// - Parameter selectImage: 选中的图片 图片颜色将由`selectColor`设置
/// - Parameter content: 对应的内容试图
let contents:[(title:String, image:UIImage, selectImage:UIImage, content:Content)]
/// 设置选中图片的前景色
let selectColor:UIColor
@State var tabIndex:Int = 0
var body: some View {
TabView(selection: $tabIndex) {
ForEach(0 ..< contents.count) { index in
contents[index].3
.tabItem {
TabItemView(title: contents[index].0,
image: contents[index].1,
selectImage: contents[index].2,
index: index,
currentIndex: $tabIndex)
}
.tag(index)
}
}.accentColor(Color(selectColor))
}
}
extension CustomTabView {
struct TabItemView: View {
let title:String
let image:UIImage
let selectImage:UIImage
let index:Int
@Binding var currentIndex:Int
var body: some View {
VStack{
if (currentIndex == index) {
Image(uiImage: selectImage)
} else {
Image(uiImage: image.withRenderingMode(.alwaysTemplate))
}
Text(title)
}
}
}
}
struct CustomTabView_Previews: PreviewProvider {
static var previews: some View {
CustomTabView(contents: [
("首页",#imageLiteral(resourceName: "icon_nav_food1"),#imageLiteral(resourceName: "icon_nav_food2"),Text("1")),
("首页",#imageLiteral(resourceName: "icon_nav_food1"),#imageLiteral(resourceName: "icon_nav_food2"),Text("2"))
], selectColor: .red)
}
}
Swift使用#if DEBUG
1 第一步在Build Settings->Swift Compiler - Custom Flags->"Other Swift Flags" 在Debug新增"-DDBUG"或者"-D DEBUG"
2 第二部Build Settings->Apple LLVM x.x - Preprocessiong->Preprocessor Macros在Debug新增"DEBUG=1"Flutter 获取当前Widget所有的子树
对于我们常用的StatefulWidget和StatelessWidget我们可以通过下面方法
createElement().debugGetDiagnosticChain()SwiftUI cornerRadius方法无法给UIViewRepresentable的UIView生成圆角
需要用UIView的方法设置圆角
view.layer.masksToBounds = true
view.layer.cornerRadius = cornerRadiusUIScroolView实现自定义分页
public func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
/// 实现自定义分页
if velocity != .zero {
/// 如果velocity不为空 则代表是用户快速拖动离开的 则滚动到下一个位置
/// 获取到当前的索引
guard let currentIndex = currentShopIndex else {
return
}
var index:Int
if velocity.x > 0 {
index = currentIndex + 1
} else {
index = currentIndex - 1
}
index = max(0, index)
index = min(index, self.currentDisplayModels.count - 1)
let point = scrollCellPoint(index: index)
targetContentOffset.pointee = point
}
}SwiftUI 自定义UINavigationBar背景颜色
struct NavigationBarModifier: ViewModifier {
var backgroundColor: UIColor?
init( backgroundColor: UIColor?) {
self.backgroundColor = backgroundColor
let coloredAppearance = UINavigationBarAppearance()
coloredAppearance.configureWithTransparentBackground()
coloredAppearance.backgroundColor = .clear
coloredAppearance.titleTextAttributes = [.foregroundColor: UIColor.white]
coloredAppearance.largeTitleTextAttributes = [.foregroundColor: UIColor.white]
UINavigationBar.appearance().standardAppearance = coloredAppearance
UINavigationBar.appearance().compactAppearance = coloredAppearance
UINavigationBar.appearance().scrollEdgeAppearance = coloredAppearance
UINavigationBar.appearance().tintColor = .white
}
func body(content: Content) -> some View {
ZStack{
content
VStack {
GeometryReader { geometry in
Color(self.backgroundColor ?? .clear)
.frame(height: geometry.safeAreaInsets.top)
.edgesIgnoringSafeArea(.top)
Spacer()
}
}
}
}
}
extension View {
public func navigationBarBackgroundColor(_ backgroundColor: UIColor?) -> some View {
self.modifier(NavigationBarModifier(backgroundColor: backgroundColor))
}
}SwiftUI .position 定位不准确
因为position是按照中心点进行偏移定位的
2022年开发笔记第二期
Flutter 中 Provider 如何监听 List 的更新
不要直接操作数组，需要先设置新数组
错误操作
list.add("hello");
notifyListeners()list.add("hello");
list = [...list];
notifyListeners()
正确操作
list = [...list];
list.add("hello");
notifyListeners();