FJPullTableView 上拉加载更多的效果实现

FJPullTableView 上拉加载更多的效果实现

  (2013-06-05 11:21:27)

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标签：  uitableview   上拉刷新   fjpulltableview   it

分类： iOS开发

项目中由于列表显示的数据比较多，我们经常要用到上拉加载更多的功能，写了一个小类实现了此功能，具体使用方法如下：

 

1. 使用方法： 

（1）导入     #import "FJPullTableView.h"

（2）使用    绑定代理FJPullTableViewDelegate, UISCrollViewDelegate

定义变量  FJPullTableView *mytv;

    mytv = [[FJPullTableView alloc] initWithFrame:CGRectMake(10, 50, 200, 200)];

    mytv.delegate = self;

    mytv.dataSource = self;

    mytv.pullDelegate = self;

    [mytv setIsNeedDisplay:YES];

    [self.view addSubview: mytv];

实现代理方法

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

    [mytv fjPullScrollViewDidScroll:scrollView];

}

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

    [mytv fjPullScrollViewDidEndDragging:scrollView];

}

- (void)beginToFetchData:(FJPullTableView *)tableView {

    NSLog(@"start load");

    //开始执行加载方法

    //模拟执行加载方法

    [self performSelector:@selector(doLoad) withObject:nil afterDelay:3];

}

- (void)doLoad {

    NSLog(@"load done");

    totalCount += 10;

    if (totalCount > 30) {

        [mytv setIsNeedDisplay:NO];

    }

    [mytv fjPullScrollViewDataSourceDidFinishedLoading:mytv];

}

注意：  加载更多执行完后

1. 判断是否还要显示上拉刷新提示

[myth setIsNeedDisplay:YES];

2. 调用[mytv fjPullScrollViewDataSourceDidFinishedLoading:mytv];

使用方法比较简单，具体代码实现如下：

 

#import

@class FJPullTableView;

@protocol FJPullTableViewDelegate

//程序中加载数据的代码在此方法中执行

- (void)beginToFetchData:(FJPullTableView *)tableView;

@end

@interface FJPullTableView : UITableView

@property (nonatomic, assign) id pullDelegate;

//该方法控制tableview是否显示上拉刷新提示，是否执行上拉刷新操作

- (void)setIsNeedDisplay:(BOOL)isNeedToDisplay;

- (void)fjPullScrollViewDidScroll:(UIScrollView *)scrollView;

- (void)fjPullScrollViewDidEndDragging:(UIScrollView *)scrollView;

//更多数据加载完成后需要调用此方法

- (void)fjPullScrollViewDataSourceDidFinishedLoading:(UIScrollView *)scrollView;

@end

#import "FJPullTableView.h"

#define PULL_LOAD_MORE    @"上拉加载更多"

#define PULL_TO_LOAD      @"松开即可加载"

#define PULL_LOADING      @"加载中..."

@interface FJPullTableView () {

    UILabel *lbLoadingInfo;

    BOOL hasLoadingInfo;

    BOOL isLoading;

    BOOL isNeedDisplay;

    UIActivityIndicatorView *indicatorView;

}

@end

@implementation FJPullTableView

@synthesize pullDelegate;

- (id)initWithFrame:(CGRect)frame

{

    self = [super initWithFrame:frame];

    if (self) {

        // Initialization code

        isNeedDisplay = YES;

    }

    return self;

}

//设置tableview是否显示上拉刷新提示

- (void)setIsNeedDisplay:(BOOL)isNeedToDisplay {

    isNeedDisplay = isNeedToDisplay;

}

//当tableview向上滚动时调用此方法

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

    if (isNeedDisplay && !isLoading) {

        if (scrollView.contentOffset.y + scrollView.frame.size.height > scrollView.contentSize.height + 60) {

            lbLoadingInfo.text = PULL_TO_LOAD;

        } else {

            if (!lbLoadingInfo) {

                lbLoadingInfo = [[UILabel alloc] initWithFrame:CGRectZero];

                lbLoadingInfo.backgroundColor = [UIColor clearColor];

                if ([[[UIDevice currentDevice] systemVersion] doubleValue] >= 6.0) {

                    lbLoadingInfo.textAlignment = NSTextAlignmentCenter;

                } else {

                    lbLoadingInfo.textAlignment = UITextAlignmentCenter;

                }

                lbLoadingInfo.font = [UIFont systemFontOfSize:12];

                lbLoadingInfo.textColor = [UIColor grayColor];

            }

            if (!hasLoadingInfo) {

                lbLoadingInfo.frame = CGRectMake(0, self.contentSize.height,self.frame.size.width, 30);

                [self addSubview:lbLoadingInfo];

                hasLoadingInfo = YES;

            }

            lbLoadingInfo.text = PULL_LOAD_MORE;

        }

    }

}

//当tableview结束拖拽时调用此方法

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

    if (isNeedDisplay && !isLoading) {

        if (scrollView.contentOffset.y + scrollView.frame.size.height > scrollView.contentSize.height + 60) {

            isLoading = YES;

            //执行加载更多操作

            if ([pullDelegate respondsToSelector:@selector(beginToFetchData:)]) {

                [self showIndicatorView];

                //执行代理方法，进行数据加载

                [pullDelegate beginToFetchData:self];

            }

        }

    }

}

//加载数据结束时执行此操作

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

    isLoading = NO;

    [self hiddenIndicatorView];

    [self reloadData];

}

- (void)showIndicatorView {

    if (!indicatorView) {

        indicatorView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

        indicatorView.frame = CGRectMake(self.frame.size.width/2 - 50, 5, 20, 20);

    }

    [indicatorView startAnimating];

    lbLoadingInfo.text = PULL_LOADING;

    [lbLoadingInfo addSubview:indicatorView];

}

- (void)hiddenIndicatorView {

    if (indicatorView) {

        [indicatorView stopAnimating];

        [indicatorView removeFromSuperview];

    }

    [lbLoadingInfo removeFromSuperview];

    hasLoadingInfo = NO;

}

@end