IOS开发笔记（2）EGOTableViewPullRefresh实现列表的下拉刷新功能


http://blog.csdn.net/xiaofansong/article/details/8260258

现在流行的列表上拉刷新基本上都是使用的EGOTableViewPullRefresh开源的类库。

1、到github上下载EGOTableViewPullRefresh

https://github.com/enormego/EGOTableViewPullRefresh

2、下载后的文件夹中包含以下内容



将EGOTableViewPullRefresh中的Resources文件夹中的所有图片全部都拷贝到自己的工程的Resources文件夹下，这些图片是下拉箭头及tableView的headerView的背景图片。在EGOTableViewPullRefresh文件夹下的Classes文件夹下的View文件夹下有两个文件，分别是EGORefreshTableHeaderView.h和EGORefreshTableHeaderView.m文件，将这两个文件放到自己的工程下。到此为止准备工作就做完了。

3、下拉是一个刷新的工作，所以需要我们添加的代码无非就是数据刷新的代码。

（1）在.h文件中添加如下代码

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#import "EGORefreshTableHeaderView.h" @interface RootViewController : UITableViewController <EGORefreshTableHeaderDelegate, UITableViewDelegate, UITableViewDataSource>{ EGORefreshTableHeaderView *_refreshHeaderView; // Reloading var should really be your tableviews datasource // Putting it here for demo purposes BOOL _reloading; } - (void)reloadTableViewDataSource; - (void)doneLoadingTableViewData;

#import "EGORefreshTableHeaderView.h"

@interface RootViewController : UITableViewController  <EGORefreshTableHeaderDelegate, UITableViewDelegate, UITableViewDataSource>{

EGORefreshTableHeaderView *_refreshHeaderView;

//  Reloading var should really be your tableviews datasource
//  Putting it here for demo purposes
BOOL _reloading;
}

- (void)reloadTableViewDataSource;
- (void)doneLoadingTableViewData;

（2）在- (void)viewDidLoad函数中添加下面的代码。

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if (_refreshHeaderView == nil) { EGORefreshTableHeaderView *view = [[EGORefreshTableHeaderView alloc] initWithFrame: CGRectMake(0.0f, self.tableView.contentSize.height, 320, 650)]; NSLog(@"%@", NSStringFromCGRect( view.frame )); view.delegate = self; [self.tableView addSubview:view]; _refreshHeaderView = view; [view release]; } // update the last update date [_refreshHeaderView refreshLastUpdatedDate];

if (_refreshHeaderView == nil) {

EGORefreshTableHeaderView *view = [[EGORefreshTableHeaderView alloc] initWithFrame: CGRectMake(0.0f, self.tableView.contentSize.height, 320, 650)];
NSLog(@"%@", NSStringFromCGRect( view.frame ));
view.delegate = self;
[self.tableView addSubview:view];
_refreshHeaderView = view;
[view release];

}

//  update the last update date
[_refreshHeaderView refreshLastUpdatedDate];

（3）在对应的.m文件中添加如下方法

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#pragma mark - #pragma mark Data Source Loading / Reloading Methods - (void)reloadTableViewDataSource{ // should be calling your tableviews data source model to reload // put here just for demo _reloading = YES; } - (void)doneLoadingTableViewData{ // model should call this when its done loading _reloading = NO; [_refreshHeaderView egoRefreshScrollViewDataSourceDidFinishedLoading:self.tableView]; } #pragma mark - #pragma mark UIScrollViewDelegate Methods - (void)scrollViewDidScroll:(UIScrollView *)scrollView{ [_refreshHeaderView egoRefreshScrollViewDidScroll:scrollView]; } - (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{ [_refreshHeaderView egoRefreshScrollViewDidEndDragging:scrollView]; } #pragma mark - #pragma mark EGORefreshTableHeaderDelegate Methods - (void)egoRefreshTableHeaderDidTriggerRefresh:(EGORefreshTableHeaderView*)view{ [self reloadTableViewDataSource]; [self performSelector:@selector(doneLoadingTableViewData) withObject:nil afterDelay:4.0]; } - (BOOL)egoRefreshTableHeaderDataSourceIsLoading:(EGORefreshTableHeaderView*)view{ return _reloading; // should return if data source model is reloading } - (NSDate*)egoRefreshTableHeaderDataSourceLastUpdated:(EGORefreshTableHeaderView*)view{ return [NSDate date]; // should return date data source was last changed }

#pragma mark -
#pragma mark Data Source Loading / Reloading Methods

- (void)reloadTableViewDataSource{

//  should be calling your tableviews data source model to reload
//  put here just for demo
_reloading = YES;

}

- (void)doneLoadingTableViewData{

//  model should call this when its done loading
_reloading = NO;
[_refreshHeaderView egoRefreshScrollViewDataSourceDidFinishedLoading:self.tableView];

}

#pragma mark -
#pragma mark UIScrollViewDelegate Methods

- (void)scrollViewDidScroll:(UIScrollView *)scrollView{

[_refreshHeaderView egoRefreshScrollViewDidScroll:scrollView];

}

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate{

[_refreshHeaderView egoRefreshScrollViewDidEndDragging:scrollView];

}

#pragma mark -
#pragma mark EGORefreshTableHeaderDelegate Methods

- (void)egoRefreshTableHeaderDidTriggerRefresh:(EGORefreshTableHeaderView*)view{

[self reloadTableViewDataSource];
[self performSelector:@selector(doneLoadingTableViewData) withObject:nil afterDelay:4.0];

}

- (BOOL)egoRefreshTableHeaderDataSourceIsLoading:(EGORefreshTableHeaderView*)view{

return _reloading; // should return if data source model is reloading

}

- (NSDate*)egoRefreshTableHeaderDataSourceLastUpdated:(EGORefreshTableHeaderView*)view{

return [NSDate date]; // should return date data source was last changed

}

4、总结

A：这个是在底部加刷新。如果在顶部加刷新那么只要修改下ViewDidload的创建代码

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EGORefreshTableHeaderView *view = [[EGORefreshTableHeaderView alloc] initWithFrame:CGRectMake(0.0f, -320.0f, self.view.frame.size.width, 320)];

EGORefreshTableHeaderView *view = [[EGORefreshTableHeaderView alloc] initWithFrame:CGRectMake(0.0f, -320.0f, self.view.frame.size.width, 320)];

B：如果想同时在顶部或者底部都加上刷新，可以参考我另外一个帖子（关于糗百，开发笔记一里面所使用的方法）

C:如果想实现在列表最后一行实现点击查询，那么可以在列表下多加一行，自己写一个类继承UItableviewcell，然后在点击事件里面做一个判断。

D:假如遇到数据刷新之后那个顶部的view还在刷新，这个可能是egoRefreshTableHeaderDidTriggerRefresh里面同步执行的代码

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- (void)egoRefreshTableHeaderDidTriggerRefresh:(EGORefreshTableHeaderView *)view { [self reloadTableViewDataSource]; [self performSelector:@selector(refresh) withObject:nil afterDelay:2.0f]; // [self refresh]; }

- (void)egoRefreshTableHeaderDidTriggerRefresh:(EGORefreshTableHeaderView *)view
{
[self reloadTableViewDataSource];
[self performSelector:@selector(refresh) withObject:nil afterDelay:2.0f];
// [self refresh];

}

这里读取数据的操作必须是异步的，要不然和tableView下拉再上弹这个动作会有很明显的延迟。