IOS几个常用功能

通过tag获取控件

MyButton *btn = (MyButton *)[self.contentView viewWithTag:tag];

通过segue跳转页面

[selfperformSegueWithIdentifier:@"playGame"sender:sender];

取消模式窗口

[selfdismissViewControllerAnimated:YEScompletion:nil];

呈现模式窗口

[selfpresentViewController:imagePicker animated:YEScompletion:nil];

设置imageview里图片按照原来比例显示

self.imageView.contentMode = UIViewContentModeScaleAspectFit;