部分代码总结7.29

UItextfield *textfield =[ [uitextfield alloc] init]textfield .contentHorizontalAlignment = UIControlContentHorizontalAlignmentCenter;
textfield .contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;textfield .placeholder= @"+++";//值textfield.delegate = self;//设置委托，如果要要使用uitextfield的方法，则要使用委托，并且添加UITextFieldDelegate
无论添加什么都可以放到contentview上

UIView *contentView = [[UIView alloc] initWithFrame:CGRectMake(380, 60, 610, 650)];

self.view = contentView;

bgImageView.userInteractionEnabled = YES;//背景图片可以操作