图片适配
1.选择Assets.xcassets—>左下角+号—>New Image Set.然后自己命一个名字
2.修改图片的Contents.json文件,修改内容如下(双击图片,选择Show in Finder,文件夹里面有一个Contents.json文件,双击打开)
{"images":[{"idiom":"iphone","scale":"1x"},{"idiom":"iphone","scale":"2x"},{"idiom":"iphone","scale":"3x"},{"idiom":"iphone","scale":"1x","subtype":"retina4"},{"idiom":"iphone","scale":"2x","subtype":"retina4"},{"idiom":"iphone","scale":"3x","subtype":"retina4"},{"idiom":"iphone","scale":"3x","subtype":"736h"},{"idiom":"iphone","scale":"2x","subtype":"667h"},{"idiom":"iphone","scale":"3x","subtype":"2436h"},{"idiom":"iphone","scale":"3x","subtype":"2688h"},{"idiom":"iphone","scale":"2x","subtype":"1792h"}],"info":{"author":"xcode","version":1}}
3.此时就可以根据不同屏幕适配不同的启动图了
4.适配完各个屏幕图片后,去LaunchScreen.storyboard搭建启动图