iOS中弹出警示框
// 警示框提示请输入
UIAlertView *alertView = [[UIAlertView alloc]initWithTitle:@"友情提示" message:@"用户名不能为空" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:@"取消", nil];
// 显示警示框
[alertView show];
// 警示框提示请输入
UIActionSheet *actionSheet = [[UIActionSheet alloc]initWithTitle:@"友情提示" delegate:nil cancelButtonTitle:@"确定" destructiveButtonTitle:@"取消" otherButtonTitles:@"请确认信息", nil];
actionSheet.actionSheetStyle = UIActionSheetStyleBlackOpaque;
[actionSheet showInView:loginView];
