SwiftUI学习<一>

1、command + option + p 刷新canvas画布

2、SwiftUI支持环境：iOS13+Swift5.1+Xcode11

3、列表List使用：

struct ContentView: View {
    var body: some View {
        List(0 ..< 5) { item in
            Image(systemName: "photo")
            VStack(alignment: .center) {
                Text("长城")
                Text("北京")
                    .font(.subheadline)
                    .foregroundColor(.secondary)
            }
        }
    }
}

4、SwiftUI导航栏，页面跳转：

struct ContentView: View {
    var body: some View {
        // 导航栏
        NavigationView {
            List(0 ..< 5) { item in
                // 点击事件
                NavigationLink(
                    destination: Text("好")) {
                    Image(systemName: "photo").cornerRadius(3.0)
                    VStack(alignment: .center) {
                        Text("长城")
                        Text("北京")
                            .font(.subheadline)
                            .foregroundColor(.secondary)
                    }
                }
            }.navigationTitle("世界地标")
        }
    }
}

5、页面跳转，页面叠加：

struct LandmarkDetail: View {
    var body: some View {
        // 叠加效果
        ZStack(alignment: .bottomTrailing) {
            Image("guide1")
                .resizable()
                .aspectRatio(contentMode: .fit)
                .navigationBarTitle("试试", displayMode: .inline)
                // 让文字靠最下显示
                .frame(minWidth: 0, maxWidth: .infinity, minHeight: 0, maxHeight: .infinity)
            Text("北京呀~")
                .font(.largeTitle)
                .foregroundColor(.secondary)
        }
    }
}

struct LandmarkDetail_Previews: PreviewProvider {
    static var previews: some View {
        // 导航栏显示
        NavigationView {
            LandmarkDetail()
        }
    }
}

6、SwiftUI页面跳转正向传值：