在swift 类中有一个方法deinit(),我们可以在其中定义类的实例将从内存中删除.我们如何知道struct将从内存中删除?
例如,
struct Vehicle { ... }
var v: Vehicle? = Vehicle()
v = nil
Run Code Online (Sandbox Code Playgroud) 我有一个平面列表
<View style={styles.container}>
<FlatList data={this.state.restaurants}
renderItem={({ item }) => this.renderItem(item.restaurant)}
keyExtractor={restaurant => restaurant.key}
ListHeaderComponent={() => this.renderHeaderComponent()}
ItemSeparatorComponent={this.renderSeparator}/>
</View>
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并在标题中包含 TextInput。我使用 TextInput 作为搜索栏。
renderHeaderComponent() {
return(
<View style={{ flexDirection: 'row', marginTop: 10, borderBottomColor: '#CED0CE', borderWidth: 1, borderColor: 'transparent' }}>
<Icon name='search' size={30} style={{ marginLeft: 10, marginRight: 10 }}/>
<TextInput
style={{height: 40, flex: 1}}
onChangeText={(text) => this.onChangeText(text)}
placeholder='Type text for search'
clearButtonMode='while-editing'
value={this.state.searchText}
/>
</View>
);
};
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在 onChangeMethod 中,我过滤了我的数据。
onChangeText(text) {
const filteredRestaurants = _.filter(this.props.list, (restaurantObject) => {
const restaurant = …Run Code Online (Sandbox Code Playgroud) 我正在使用模式MVVM+Coordinator。我的每个控制器都是由coordinators. 但是,当点击Navigation控制器的后退按钮时,停止我的协调器的正确方法是什么?
class InStoreMainCoordinator: NavigationCoordinatorType, HasDisposeBag {
let container: Container
enum InStoreMainChildCoordinator: String {
case menu = "Menu"
case locations = "Locations"
}
var navigationController: UINavigationController
var childCoordinators = [String: CoordinatorType]()
init(navigationController: UINavigationController, container: Container) {
self.navigationController = navigationController
self.container = container
}
func start() {
let inStoreMainViewModel = InStoreMainViewModel()
let inStoreMainController = InStoreMainController()
inStoreMainController.viewModel = inStoreMainViewModel
navigationController.pushViewController(inStoreMainController, animated: true)
}
}
Run Code Online (Sandbox Code Playgroud) 我有从嵌套数组生成flatted数组的函数.它适用于int数组.
let array: [Any] = [1, 2, [3]]
func makeFlatArray(_ array: [Any]) -> [Int] {
var flatArray = [Int]()
for item in array {
if let item = item as? Int {
flatArray.append(item)
} else if let item = item as? [Any] {
let result = makeFlatArray(item)
flatArray += result
}
}
return flatArray
}
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但我想让它变得通用,我在尝试时遇到了错误.
func makeFlatArrayGeneric<T>(_ array: [Any]) -> [T] {
var flatArray = [T]()
for item in array {
if let item = item as? T { …Run Code Online (Sandbox Code Playgroud) 在ARC(自动引用计数)工作时在Objective-C或Swift中?在编译阶段还是在运行时阶段?那为什么重要呢?
UserDefaults在Swift中是否安全?怎么检查?例如,如果有10个线程使用UserDafaults写入数据.我们如何检查线程安全?
据我所知,在 Objective-C 中,所有类都继承自 NSObject 类。斯威夫特呢?我们出于什么目的需要在 Swift 中继承 NSObject?
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