两个方法中的区别
NSLog(@"[UIScreen mainScreen] bounds].size.width%f",[[UIScreen mainScreen] bounds].size.width);
打印出来的结果是
2016-07-22 17:00:02.084 huibamTracking[22437:373638] [UIScreen mainScreen] bounds].size.width320.000000
第二个
NSLog(@"[UIScreen mainScreen] bounds].size.width%f",self.view.frame.size.width);
2016-07-22 17:00:02.084 huibamTracking[22437:373638] [UIScreen mainScreen] bounds].size.width375.000000