iOS实现简单的二级菜单效果

首先来看看要实现的效果图

示例代码如下

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#import "viewcontroller.h"
#import "collectionviewcell.h"
#import "collectionsectionview.h"
@interface viewcontroller ()<uicollectionviewdelegateflowlayout,uicollectionviewdatasource>
@property (nonatomic,strong)uicollectionview *collectionview;
@property (nonatomic,copy)nsstring *leftorright;
@property (nonatomic,strong)nsindexpath *clickindexpath;
@end
static nsstring *cellidentifier = @"collectionviewcell";
static nsstring *sectionidentifier = @"collectionsectionview";
@implementation viewcontroller

- (void)viewdidload {
 [super viewdidload];
 // do any additional setup after loading the view, typically from a nib.
 uicollectionviewflowlayout *flowlayout = [[uicollectionviewflowlayout alloc] init];
 flowlayout.itemsize = cgsizemake(50, 25);
 flowlayout.minimumlinespacing = 0;
 flowlayout.minimuminteritemspacing = 0;
 flowlayout.headerreferencesize = cgsizemake(0, 40);
 flowlayout.sectioninset = uiedgeinsetsmake(0, 0, 0, 0);
 self.collectionview = [[uicollectionview alloc] initwithframe:self.view.frame collectionviewlayout:flowlayout];
 _collectionview.backgroundcolor = [uicolor whitecolor];
 _collectionview.delegate = self;
 _collectionview.datasource = self;
 [_collectionview registerclass:[collectionviewcell class] forcellwithreuseidentifier:cellidentifier];
 [_collectionview registerclass:[collectionsectionview class] forsupplementaryviewofkind:uicollectionelementkindsectionheader withreuseidentifier:sectionidentifier];
 [self.view addsubview:_collectionview];
}
- (nsinteger)numberofsectionsincollectionview:(uicollectionview *)collectionview{
 return 3;
}
- (nsinteger)collectionview:(uicollectionview *)collectionview numberofitemsinsection:(nsinteger)section{
 if (self.clickindexpath.section == section) {
  if (self.clickindexpath.section == 0 && [self.leftorright isequaltostring:@"left"]) {
   return 3;
  }
  if (self.clickindexpath.section == 0 && [self.leftorright isequaltostring:@"right"]) {
   return 4;
  }
  if (self.clickindexpath.section == 1 && [self.leftorright isequaltostring:@"left"]) {
   return 10;
  }
  if (self.clickindexpath.section == 1 && [self.leftorright isequaltostring:@"right"]) {
   return 8;
  }
  if (self.clickindexpath.section == 2 && [self.leftorright isequaltostring:@"left"]) {
   return 33;
  }
  if (self.clickindexpath.section == 2 && [self.leftorright isequaltostring:@"right"]) {
   return 6;
  }
 }
 return 0;
}
- (uicollectionviewcell *)collectionview:(uicollectionview *)collectionview cellforitematindexpath:(nsindexpath *)indexpath{
 collectionviewcell *cell = [collectionview dequeuereusablecellwithreuseidentifier:cellidentifier forindexpath:indexpath];
 cell.label.text = [nsstring stringwithformat:@"%ld-%ld",indexpath.section,indexpath.row];
 return cell;
}
- (uicollectionreusableview *)collectionview:(uicollectionview *)collectionview viewforsupplementaryelementofkind:(nsstring *)kind atindexpath:(nsindexpath *)indexpath{
 if ([kind isequaltostring:uicollectionelementkindsectionheader]) {
  collectionsectionview *sectionview = [collectionview dequeuereusablesupplementaryviewofkind:kind withreuseidentifier:sectionidentifier forindexpath:indexpath];
  sectionview.backgroundcolor = [uicolor lightgraycolor];
  sectionview.leftstr = @"家具";
  sectionview.rightstr = @"家电";
  [sectionview custombtnhandelaction:^(nsstring *leftorright) {
   self.clickindexpath = indexpath;
   self.leftorright = leftorright;
   [collectionview reloaddata];
  }];
  return sectionview;
 }
 return nil;
}
- (void)didreceivememorywarning {
 [super didreceivememorywarning];
 // dispose of any resources that can be recreated.
}

#import <uikit/uikit.h>
typedef void(^btnhandleaction)(nsstring *leftorright);
@interface collectionsectionview : uicollectionreusableview
@property (nonatomic,copy)nsstring *leftstr;
@property (nonatomic,copy)nsstring *rightstr;
- (void)custombtnhandelaction:(btnhandleaction)action;
@end

#import "collectionsectionview.h"
@interface collectionsectionview ()
@property (nonatomic,strong)uibutton *leftbtn;
@property (nonatomic,strong)uibutton *rightbtn;
@property (nonatomic,copy)btnhandleaction btnhandelaction;
@end
@implementation collectionsectionview
- (instancetype)initwithframe:(cgrect)frame
{
 self = [super initwithframe:frame];
 if (self) {
  [self setup];
 }
 return self;
}
- (uibutton *)leftbtn{
 if (!_leftbtn) {
  self.leftbtn = [uibutton buttonwithtype:(uibuttontypecustom)];
  _leftbtn.tag = 2000;
  _leftbtn.frame = cgrectmake(1, 1, self.frame.size.width / 2 - 2, self.frame.size.height - 2);
  _leftbtn.backgroundcolor = [uicolor whitecolor];
  [_leftbtn addtarget:self action:@selector(btnaction:) forcontrolevents:(uicontroleventtouchupinside)];
 }
 return _leftbtn;
}
- (uibutton *)rightbtn{
 if (!_rightbtn) {
  self.rightbtn = [uibutton buttonwithtype:(uibuttontypecustom)];
  _rightbtn.tag = 2001;
  _rightbtn.frame = cgrectmake(self.frame.size.width / 2 + 1, 1, self.frame.size.width / 2 - 2, self.frame.size.height - 2);
  _rightbtn.backgroundcolor = [uicolor whitecolor];
  [_rightbtn addtarget:self action:@selector(btnaction:) forcontrolevents:(uicontroleventtouchupinside)];
 }
 return _rightbtn;
}
- (void)btnaction:(uibutton *)sender{
 nsinteger tag = sender.tag;
 if (tag == 2000) {
  self.btnhandelaction(@"left");
 }
 if (tag == 2001) {
  self.btnhandelaction(@"right");
 }
}
- (void)custombtnhandelaction:(btnhandleaction)action{
 self.btnhandelaction = action;
}
- (void)setup{
 [self addsubview:self.leftbtn];
 [self addsubview:self.rightbtn];
}
- (void)setleftstr:(nsstring *)leftstr{
 [self.leftbtn settitle:leftstr forstate:(uicontrolstatenormal)];
 [self.leftbtn settitlecolor:[uicolor blackcolor] forstate:(uicontrolstatenormal)];
}
- (void)setrightstr:(nsstring *)rightstr{
 [self.rightbtn settitle:rightstr forstate:(uicontrolstatenormal)];
 [self.rightbtn settitlecolor:[uicolor blackcolor] forstate:(uicontrolstatenormal)];
}
@end

总结

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