如何使用UITableView中的标题部分展开和折叠行 [英] How to expand and collapse rows using header section in a UITableView
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问题描述
我有一个表格视图。现在我想通过点击节标题来折叠和展开行。换句话说,当我点击标题时,行显示该部分。我该怎么做?
I have a table view. Now I want to collapse and expand rows by tapping on the section header. In other words, when I tap the header the rows display for that section. How can I do this?
推荐答案
我起草了一些代码来给你这个想法。我们的概念是跟踪 NSMutableSet
中的折叠部分,并根据该部分的用户触摸添加/删除它。折叠/展开动画实际上是添加/删除单元格的动画。
I draft up some code to give you the idea. The concept is we keep track of collapsed section in NSMutableSet
and add/remove it according to the user touch on the section. The collapse/expand animation is actually the animation of adding/removing cells.
#import "ViewController.h"
@interface ViewController () < UITableViewDataSource, UITableViewDelegate> {
NSMutableSet* _collapsedSections;
}
@property (nonatomic, weak) IBOutlet UITableView* tableView;
@end
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
_collapsedSections = [NSMutableSet new];
}
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 3;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [_collapsedSections containsObject:@(section)] ? 0 : 10;
}
-(NSArray*) indexPathsForSection:(int)section withNumberOfRows:(int)numberOfRows {
NSMutableArray* indexPaths = [NSMutableArray new];
for (int i = 0; i < numberOfRows; i++) {
NSIndexPath* indexPath = [NSIndexPath indexPathForRow:i inSection:section];
[indexPaths addObject:indexPath];
}
return indexPaths;
}
-(void)sectionButtonTouchUpInside:(UIButton*)sender {
sender.backgroundColor = [UIColor greenColor];
[self.tableView beginUpdates];
int section = sender.tag;
bool shouldCollapse = ![_collapsedSections containsObject:@(section)];
if (shouldCollapse) {
int numOfRows = [self.tableView numberOfRowsInSection:section];
NSArray* indexPaths = [self indexPathsForSection:section withNumberOfRows:numOfRows];
[self.tableView deleteRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationTop];
[_collapsedSections addObject:@(section)];
}
else {
int numOfRows = 10;
NSArray* indexPaths = [self indexPathsForSection:section withNumberOfRows:numOfRows];
[self.tableView insertRowsAtIndexPaths:indexPaths withRowAnimation:UITableViewRowAnimationTop];
[_collapsedSections removeObject:@(section)];
}
[self.tableView endUpdates];
//[_tableView reloadData];
}
-(UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
UIButton* result = [UIButton buttonWithType:UIButtonTypeCustom];
[result addTarget:self action:@selector(sectionButtonTouchUpInside:) forControlEvents:UIControlEventTouchUpInside];
result.backgroundColor = [UIColor blueColor];
[result setTitle:[NSString stringWithFormat:@"Section %d", section] forState:UIControlStateNormal];
result.tag = section;
return result;
}
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell* result = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cell"];
result.textLabel.text = [NSString stringWithFormat:@"Cell %d", indexPath.row];
return result;
}
@end
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