1. 模态页面弹出 默认样式 xcode11

/*
 Defines the presentation style that will be used for this view controller when it is presented modally. Set this property on the view controller to be presented, not the presenter.
 If this property has been set to UIModalPresentationAutomatic, reading it will always return a concrete presentation style. By default UIViewController resolves UIModalPresentationAutomatic to UIModalPresentationPageSheet, but system-provided subclasses may resolve UIModalPresentationAutomatic to other concrete presentation styles. Participation in the resolution of UIModalPresentationAutomatic is reserved for system-provided view controllers.
 Defaults to UIModalPresentationAutomatic on iOS starting in iOS 13.0, and UIModalPresentationFullScreen on previous versions. Defaults to UIModalPresentationFullScreen on all other platforms.
 */

@property(nonatomic,assign) UIModalPresentationStyle modalPresentationStyle API_AVAILABLE(ios(3.2));

2. webwview 桥接线程问题,主线程调用桥接回调

void _WebThreadLock(), 0x116cc0030: Tried to obtain the web lock from a thread other than the main thread or the web thread. This may be a result of calling to UIKit from a secondary thread. Crashing now...

3.不能在子线程创建 uiviewcontroller alloc

4. UIModalTransitionStylePartialCurl 使用异常

reason: 'Application tried to present UIModalTransitionStylePartialCurl to or from non-fullscreen view controller <ConversationListController:

https://developer.apple.com/documentation/uikit/uimodaltransitionstyle/partialcurl

5. UISearchBar 搜索栏私有属性访问

'Access to UISearchBar's _searchField ivar is prohibited. This is an application bug'

            UITextField *searchField ;

#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 130000

            if (@available(iOS 13.0, *)) {
                searchField = self.searchBar.searchTextField;
            } else {
                searchField = [self.searchBar valueForKey:@"_searchField"];
            }
#else

            searchField = [self.searchBar valueForKey:@"_searchField"];

#endif

6.蓝牙权限

This app has crashed because it attempted to access privacy-sensitive data without a usage description.  The app's Info.plist must contain an NSBluetoothAlwaysUsageDescription key with a string value explaining to the user how the app uses this data.

https://developer.apple.com/documentation/bundleresources/information_property_list/nsbluetoothalwaysusagedescription