第十二章：表视图常用UI范例——实现折叠列表，以及cell增加滑动手势

1.首先自定义一个UIView 用来作为SectionHeader，用一个大的button覆盖整个View

MKAccordionButton.h文件

#import <UIKit/UIKit.h>

@interface MKAccordionButton : UIView

@property (nonatomic,weak) IBOutlet UIButton *mainButton;
                        // 返回值  快名称              参数
@property (nonatomic,copy) void(^buttonTappedHandler)();

@end

MKAccordionButton.m文件

这里，需要注意的就是使用button的点击事件来调用块

#import "MKAccordionButton.h"

@implementation MKAccordionButton

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // Initialization code
    }
    return self;
}

- (void)awakeFromNib{
    //样式设置
    self.layer.borderColor = [UIColor colorWithWhite:0.6 alpha:0.6].CGColor;
    self.layer.borderWidth = 1.0f;
    [super awakeFromNib];
}

- (IBAction)buttonTapped:(id)sender
{
    //如果块不为nil，则调用块
    if(self.buttonTappedHandler)
        self.buttonTappedHandler();
}

@end

2.在TableViewController中，实现块的方法

//设置Section头部的View
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
    //根据nib实例化对象
    MKAccordionButton *button = [[[UINib nibWithNibName:@"MKAccordionButton" bundle:nil] instantiateWithOwner:self options:nil] objectAtIndex:0];
    
    [button.mainButton setTitle:[[self.objects allKeys] objectAtIndex:section] forState:UIControlStateNormal];
    
    //设置块的方法体
    button.buttonTappedHandler=^{
        [self openAccordionAtIndex:section];
    };
    
    return button;
}

具体tableVIew的操作

//主要方法，点击的sectionTitle时候调用
- (void)openAccordionAtIndex:(int) index{
    NSMutableArray *indexPaths = [NSMutableArray array];
    
    //得到当前展开的section的行数
    int sectionCount = [[self.objects objectForKey:[[self.objects allKeys] objectAtIndex:self.currentlyExpandedIndex]] count];
    
    //得到所有当前展开的行的indexPath
    for (int i=0; i<sectionCount; i++) {
        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:i inSection:self.currentlyExpandedIndex];
        [indexPaths addObject:indexPath];
    }
    
    //重要！！！必须将其设置为一个不存在的索引，否则出错
    //具体原因不太清楚，各位大大知道的话，帮忙评论告诉我下，谢谢。
    self.currentlyExpandedIndex=-2;
    
    //删除刚才展开的indexPaths,将后面的行上移
    [self.tableView deleteRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationTop];
    
    //将当前展开设置为点击的索引
    self.currentlyExpandedIndex = index;
    //得当当前点击的section拥有的行数
    sectionCount = [[self.objects objectForKey:[[self.objects allKeys] objectAtIndex:self.currentlyExpandedIndex]] count];
    
    [indexPaths removeAllObjects];
    
    //将其加入paths中
    for (int i=0; i<sectionCount; i++) {
        NSIndexPath *indexPath = [NSIndexPath indexPathForRow:i inSection:self.currentlyExpandedIndex];
        [indexPaths addObject:indexPath];
    }
    
    //动画，将这些行加入TableView中
    double delayInSeconds = 0.35;
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
    dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
        [self.tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationFade];
    });
    
    [self.tableView endUpdates];
}

3.创建tableViewCell并给予手势

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell"];
    if(!cell)
    {
        cell = [[UITableViewCell alloc] init];
    }
    
    NSString *str = [[self.objects objectForKey:[[self.objects allKeys] objectAtIndex:indexPath.section]] objectAtIndex:indexPath.row];
    
    cell.textLabel.text = str;
    
    //创建手势滑动 手指在单元格滑动
    UISwipeGestureRecognizer *swipeGestureRight = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
    //判断收拾是否在View中
    if(![swipeGestureRight respondsToSelector:@selector(locationInView:)])
    {
        swipeGestureRight=nil;
    }else{
        swipeGestureRight.delegate = self;
        //手指个数为1
        swipeGestureRight.numberOfTouchesRequired = 1;
        //指定手指滑动方向，只能指定一个方向
        swipeGestureRight.direction = UISwipeGestureRecognizerDirectionRight;
        
        [cell.contentView addGestureRecognizer:swipeGestureRight];
    }
    
    return cell;
}

手势的Selector方法

- (void)handleGesture:(UISwipeGestureRecognizer *)gestureRecognizer
{
    // 这个view是手势所属的view，也就是增加手势的那个view
    UIView *cellView = [gestureRecognizer view];
    
    //direction属性： 用来指明手势滑动的方向的。
    UISwipeGestureRecognizerDirection direction = gestureRecognizer.direction;
    switch (direction) {
        case UISwipeGestureRecognizerDirectionRight:
        {
            NSLog(@"direction==UISwipeGestureRecognizerDirectionRight");
            break;
        }
        case UISwipeGestureRecognizerDirectionLeft:
        {
            NSLog(@"direction==UISwipeGestureRecognizerDirectionLeft");
            break;
        }
        case UISwipeGestureRecognizerDirectionUp:
        {
            NSLog(@"direction==UISwipeGestureRecognizerDirectionUp");
            break;
        }
        case UISwipeGestureRecognizerDirectionDown:
        {
            NSLog(@"direction==UISwipeGestureRecognizerDirectionDown");
            break;
        }
        default:
            break;
    }
}

更多手势详解： UIGestureRecognizer学习笔记
Demo下载地址：MKAccordion_Demo