一 Xcode12编译报错:

error: can't exec 'copypng' (No such file or directory) Command copypng failed with exit code 71;在Xcode12中编译时有这个报错,因项目需求,以前的Xcode11还要保留,再加上mac空间小,安装的时候删除了一些文件,借助SD解压,然后在复制到mac的应用程序中,就报错了, 所以重新安装;详见:https://stackoverflow.com/questions/40998809/command-copypng-failed-with-exit-code-71

二 UIPageControl自定义适配

if (@available(iOS 14.0,*)) {
            // 先去遍历试图
            if (![self findIndicatorContentView]) {
                for (int i = 0; i < self.numberOfPages; i++) {
                    // 图片无法正确显示 有bug
                 if (i == self.currentPage) {
                      [self setIndicatorImage:[self.inactiveImage imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate] forPage:self.currentPage];
                  }else{
                       [self setIndicatorImage:[self.activeImage imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate] forPage:i];
                  }
                    //
    
               }
                
            }

            // 自定义样式
            int temp = 0;
            for ( id view in [self findIndicatorContentView].subviews) {
                
                if ([view isKindOfClass:[UIImageView class]]) {
                    
                    if (self.currentTintColor) {
                        self.currentPageIndicatorTintColor = self.currentTintColor;
                        //self.currentPageIndicatorTintColor = [UIColor orangeColor];
                    }
                    
                    if (self.inactiveTintColor) {
                        self.pageIndicatorTintColor = self.inactiveTintColor;
                        //self.pageIndicatorTintColor = [UIColor grayColor];
                    }

                    UIImageView * imageView = (UIImageView *)view;
                    //imageView.contentMode = UIViewContentModeCenter;
                    if (temp == self.currentPage) {
                        imageView.image = [self.inactiveImage imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
                    }else{
                        imageView.image = [self.activeImage imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
                    }
                    
                }
                
                temp++;
            }
        
        }

-(UIView *)findIndicatorContentView{
    Class contentViewClass = NSClassFromString(@"_UIPageControlContentView");
    
    Class indicatorContentViewClass = NSClassFromString(@"_UIPageControlIndicatorContentView");
    
    for (UIView *contentView in self.subviews) {
        if ([contentView isKindOfClass:contentViewClass]) {
            for (UIView *indicatorContentView in contentView.subviews) {
                if ([indicatorContentView isKindOfClass:indicatorContentViewClass]) {
                    return indicatorContentView;
                }
            }
        }
    }
    
    return nil;
    
}

参考https://www.cnblogs.com/4zjq/archive/2020/11/25/14034333.html

三 UITableViewController 在iOS14上,打印self.view为

 <UITableView: 0x1080c4000; frame = (0 0; 0 0); clipsToBounds = YES; autoresize = W+H; gestureRecognizers = <NSArray: 0x280789290>; layer = <CALayer: 0x280de3460>; contentOffset: {0, 0}; contentSize: {0, 0}; adjustedContentInset: {0, 0, 0, 0}; dataSource: <_UIFilteredDataSource: 0x280789080>>  

self.view.frame.size.width == 0 大坑啊!!!

四 Widget的适配

3.1 在iOS14上,推出了WidgetKit框架,还没有用到,但要沿用以前的Today Extension ,界面变形,需要适配.

-(UIView *)noneDataView{
    if (!_noneDataView) {
        _noneDataView = [[UIView alloc] initWithFrame:CGRectZero];
        if (@available(iOS 14.0 , *)) {
            _noneDataView.frame = CGRectMake(0, 0,ScreenWidth - 40,widgetHeigth );
        }else{
            _noneDataView.frame = CGRectMake(0, 0,widgetWidth,widgetHeigth );
        }
    }
    return _noneDataView;
}

3.2 学习WidgetKit

(1) 在学习WidgetKit之前,需要先调研SwiftUI

参考一些优质博文:
https://gitee.com/TheAlgorithms/SwiftUI?utm_source=alading&utm_campaign=repo#Text_D
http://www.zyiz.net/tech/detail-141529.html

(2) supportedFamilies:

默认情况下只有一个widget WidgetConfiguration 支持3种尺寸 supportedFamilies 赋值4个卡片 也展示3个 ,可以设置2个卡片,默认打开第一个卡片.展示为小,中,大.

.supportedFamilies([.systemSmall,.systemMedium,.systemLarge]

.supportedFamilies([.systemMedium,.systemSmall,.systemLarge]

(3) 自定义多个widget

@main
/// 自定义widget 多个
struct HunterWidgets:WidgetBundle {
    @WidgetBundleBuilder
    var body: some Widget{
        PoetryWidget1();
        PoetryWidget2();
        PoetryWidget3();

    }

// 小
struct PoetryWidget1: Widget {
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: "TestWidgetIOS14_1", provider: PoetryProvider()) { entry in
            PoetryWidgetView(entry: entry)
        }
        .configurationDisplayName("你的世界真好")
        .description("描述美妙不可言传")
        .supportedFamilies([.systemSmall])
    }
}
//中
struct PoetryWidget2: Widget {
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: "TestWidgetIOS14_2", provider: PoetryProvider()) { entry in
            PoetryWidgetView(entry: entry)
        }
        .configurationDisplayName("每日一湿")
        .description("优文章")
        .supportedFamilies([.systemMedium])
    }
}
// 小
struct PoetryWidget3: Widget {
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: "TestWidgetIOS14_3", provider: PoetryProvider()) { entry in
            PoetryWidgetView(entry: entry)
        }
        .configurationDisplayName("每日三湿")
        .description("我的文章")
        .supportedFamilies([.systemSmall])
    }
}

(4) list组件无法再WidgetKit上使用

81CD576DBFE9BA4F683CE2BBABA8208D.png

4 objc_msgSender()报错

objc_msgSend(self, @selector(setName:),str);改成((id (*)(Class _Nullable, SEL _Nonnull, NSString *)) (void *) objc_msgSend)(self, @selector(setName:),str)

objc_msgSend(observer, @selector(observeValueForKeyPath:ofObject:change:context:),@"name",self,@{@"new":str},nil);改成 ((id (*)(id _Nullable,SEL _Nonnull ,NSString *, Class _Nullable,NSDictionary*,NSNull*)) (void *) objc_msgSend)(observer, @selector(observeValueForKeyPath:ofObject:change:context:),@"name",self,@{@"new":str},nil);