【代码笔记】下拉菜单

一，效果图。

二，工程图。

三，代码。

RootViewController.h

#import <UIKit/UIKit.h>

@interface RootViewController : UIViewController

@end

RootViewController.m

#import "RootViewController.h"
#import "NIDropDown.h"

@interface RootViewController ()

@end

@implementation RootViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    [email protected]"DropDown";

    UIButton *button=[UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame=CGRectMake(10, 100, 150,30);
    button.backgroundColor=[UIColor redColor];
    [button addTarget:self action:@selector(doClickAction:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];

}
-(void)doClickAction:(UIButton *)btn
{
     NSArray *dataArray=[NSArray arrayWithObjects:@"1",@"2",@"3",@"4",@"5", nil];

    NIDropDown *dropDown=[[NIDropDown alloc]init];
    [dropDown showDropDown:btn andHeight:[dataArray count]*36 andData:dataArray];
    [self.view addSubview:dropDown];
}