The image set has 3 unassgined children

Asset.xcassets 找到对应的警告的图片

点开图片 show in finder ，你会发现缺少 Contents.json文件，从其他正常显示的图片中copy一份Contents.json文件过来，然后把下面xx替换成你的图片名称即可

只要修改这个文件即可： { "images" : [ { "idiom" : "universal", "filename" : "xx.png", "scale" : "1x" }, { "idiom" : "universal", "filename" : "xx@2x.png", "scale" : "2x" }, { "idiom" : "universal", "filename" : "xx@3x.png", "scale" : "3x" } ], "info" : { "version" : 1, "author" : "xcode" } }