自从 Tweetie 大获成功以后，下拉刷新几乎成了所有 App 的内容更新操作方式。如果你不想落入俗套，可以看看下面这段 CocoaChina 会员 “diyago” 分享的上提刷新代码。
下面是.h文件的代码
//
// EGORefreshTableHeaderView.h
// Demo
//
// Created by Devin Doty on 10/14/09October14.
// Copyright 2009 enormego. All rights reserved.
//
//修改人：禚来强 iphone开发qq群：79190809 邮箱：zhuolaiqiang@gmail.com
//原文地址：http://blog.csdn.net/diyagoanyhacker/archive/2011/05/24/6441805.aspx
#import <UIKit/UIKit.h>
#import <QuartzCore/QuartzCore.h>
typedef enum{
EGOOPullRefreshPulling = 0,
EGOOPullRefreshNormal,
EGOOPullRefreshLoading,
} EGOPullRefreshState;
@protocol EGORefreshTableHeaderDelegate;
@interface EGORefreshTableHeaderView : UIView {
id _delegate;
EGOPullRefreshState _state;
UILabel *_lastUpdatedLabel;
UILabel *_statusLabel;
CALayer *_arrowImage;
UIActivityIndicatorView *_activityView;
}
@property(nonatomic,assign) id <EGORefreshTableHeaderDelegate> delegate;
- (void)refreshLastUpdatedDate;
- (void)egoRefreshScrollViewDidScroll:(UIScrollView *)scrollView;
- (void)egoRefreshScrollViewDidEndDragging:(UIScrollView *)scrollView;
- (void)egoRefreshScrollViewDataSourceDidFinishedLoading:(UIScrollView *)scrollView;
@end
@protocol EGORefreshTableHeaderDelegate
- (void)egoRefreshTableHeaderDidTriggerRefresh:(EGORefreshTableHeaderView*)view;
- (BOOL)egoRefreshTableHeaderDataSourceIsLoading:(EGORefreshTableHeaderView*)view;
@optional
- (NSDate*)egoRefreshTableHeaderDataSourceLastUpdated:(EGORefreshTableHeaderView*)view;
@end
下面是.m文件的代码
//
// EGORefreshTableHeaderView.m
// Demo
//
//修改人：禚来强 iphone开发qq群：79190809 邮箱：zhuolaiqiang@gmail.com
//
#define RefreshViewHight 65.0f
#import "EGORefreshTableHeaderView.h"
#define TEXT_COLOR [UIColor colorWithRed:87.0/255.0 green:108.0/255.0 blue:137.0/255.0 alpha:1.0]
#define FLIP_ANIMATION_DURATION 0.18f
@interface EGORefreshTableHeaderView (Private)
- (void)setState:(EGOPullRefreshState)aState;
@end
@implementation EGORefreshTableHeaderView
@synthesize delegate=_delegate;
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame: frame];
if (self) {
self.autoresizingMask = UIViewAutoresizingFlexibleWidth;
self.backgroundColor = [UIColor colorWithRed:226.0/255.0 green:231.0/255.0 blue:237.0/255.0 alpha:1.0];
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0.0f, RefreshViewHight - 30.0f, self.frame.size.width, 20.0f)];
label.autoresizingMask = UIViewAutoresizingFlexibleWidth;
label.font = [UIFont systemFontOfSize:12.0f];
label.textColor = TEXT_COLOR;
label.shadowColor = [UIColor colorWithWhite:0.9f alpha:1.0f];
label.shadowOffset = CGSizeMake(0.0f, 1.0f);
label.backgroundColor = [UIColor clearColor];
label.textAlignment = UITextAlignmentCenter;
[self addSubview:label];
_lastUpdatedLabel=label;
[label release];
label = [[UILabel alloc] initWithFrame:CGRectMake(0.0f, RefreshViewHight - 48.0f, self.frame.size.width, 20.0f)];
label.autoresizingMask = UIViewAutoresizingFlexibleWidth;
label.font = [UIFont boldSystemFontOfSize:13.0f];
label.textColor = TEXT_COLOR;
label.shadowColor = [UIColor colorWithWhite:0.9f alpha:1.0f];
label.shadowOffset = CGSizeMake(0.0f, 1.0f);
label.backgroundColor = [UIColor clearColor];
label.textAlignment = UITextAlignmentCenter;
[self addSubview:label];
_statusLabel=label;
[label release];
CALayer *layer = [CALayer layer];
layer.frame = CGRectMake(25.0f, RefreshViewHight - RefreshViewHight, 30.0f, 55.0f);
layer.contentsGravity = kCAGravityResizeAspect;
layer.contents = (id)[UIImage imageNamed:@"blueArrow.png"].CGImage;
#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 40000
if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)]) {
layer.contentsScale = [[UIScreen mainScreen] scale];
}
#endif
[[self layer] addSublayer:layer];
_arrowImage=layer;
UIActivityIndicatorView *view = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
view.frame = CGRectMake(25.0f, RefreshViewHight - 38.0f, 20.0f, 20.0f);
[self addSubview:view];
_activityView = view;
[view release];
[self setState:EGOOPullRefreshNormal];
}
return self;
}
//
// EGORefreshTableHeaderView.h
// Demo
//
// Created by Devin Doty on 10/14/09October14.
// Copyright 2009 enormego. All rights reserved.
//
//修改人：禚来强 iphone开发qq群：79190809 邮箱：zhuolaiqiang@gmail.com
//原文地址：http://blog.csdn.net/diyagoanyhacker/archive/2011/05/24/6441805.aspx
#pragma mark -
#pragma mark Setters
- (void)refreshLastUpdatedDate {
if ([_delegate respondsToSelector:@selector(egoRefreshTableHeaderDataSourceLastUpdated:)]) {
NSDate *date = [_delegate egoRefreshTableHeaderDataSourceLastUpdated:self];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
[formatter setAMSymbol:@"上午"];
[formatter setPMSymbol:@"下午"];
[formatter setDateFormat:@"yyyy/MM/dd hh:mm:a"];
_lastUpdatedLabel.text = [NSString stringWithFormat:@"最后更新: %@", [formatter stringFromDate:date]];
[[NSUserDefaults standardUserDefaults] setObject:_lastUpdatedLabel.text forKey:@"EGORefreshTableView_LastRefresh"];
[[NSUserDefaults standardUserDefaults] synchronize];
[formatter release];
} else {
_lastUpdatedLabel.text = nil;
}
}
- (void)setState:(EGOPullRefreshState)aState{
switch (aState) {
case EGOOPullRefreshPulling:
_statusLabel.text = NSLocalizedString(@"松开即可更新...", @"松开即可更新...");
[CATransaction begin];
[CATransaction setAnimationDuration:FLIP_ANIMATION_DURATION];
_arrowImage.transform = CATransform3DMakeRotation((M_PI / 180.0) * 180.0f, 0.0f, 0.0f, 1.0f);
[CATransaction commit];
break;
case EGOOPullRefreshNormal:
if (_state == EGOOPullRefreshPulling) {
[CATransaction begin];
[CATransaction setAnimationDuration:FLIP_ANIMATION_DURATION];
_arrowImage.transform = CATransform3DIdentity;
[CATransaction commit];
}
_statusLabel.text = NSLocalizedString(@"上拉即可更新...", @"上拉即可更新...");
[_activityView stopAnimating];
[CATransaction begin];
[CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions];
_arrowImage.hidden = NO;
_arrowImage.transform = CATransform3DIdentity;
[CATransaction commit];
[self refreshLastUpdatedDate];
break;
case EGOOPullRefreshLoading:
_statusLabel.text = NSLocalizedString(@"加载中...", @"加载中...");
[_activityView startAnimating];
[CATransaction begin];
[CATransaction setValue:(id)kCFBooleanTrue forKey:kCATransactionDisableActions];
_arrowImage.hidden = YES;
[CATransaction commit];
break;
default:
break;
}
_state = aState;
}
#pragma mark -
#pragma mark ScrollView Methods
//手指屏幕上不断拖动调用此方法
- (void)egoRefreshScrollViewDidScroll:(UIScrollView *)scrollView {
if (_state == EGOOPullRefreshLoading) {
CGFloat offset = MAX(scrollView.contentOffset.y * -1, 0);
offset = MIN(offset, 60);
scrollView.contentInset = UIEdgeInsetsMake(0.0, 0.0f, RefreshViewHight, 0.0f);
} else if (scrollView.isDragging) {
BOOL _loading = NO;
if ([_delegate respondsToSelector:@selector(egoRefreshTableHeaderDataSourceIsLoading:)]) {
_loading = [_delegate egoRefreshTableHeaderDataSourceIsLoading:self];
}
if (_state == EGOOPullRefreshPulling && scrollView.contentOffset.y + (scrollView.frame.size.height) < scrollView.contentSize.height + RefreshViewHight && scrollView.contentOffset.y > 0.0f && !_loading) {
[self setState:EGOOPullRefreshNormal];
} else if (_state == EGOOPullRefreshNormal && scrollView.contentOffset.y + (scrollView.frame.size.height) > scrollView.contentSize.height + RefreshViewHight && !_loading) {
[self setState:EGOOPullRefreshPulling];
}
if (scrollView.contentInset.bottom != 0) {
scrollView.contentInset = UIEdgeInsetsZero;
}
}
}
//当用户停止拖动，并且手指从屏幕中拿开的的时候调用此方法
- (void)egoRefreshScrollViewDidEndDragging:(UIScrollView *)scrollView {
BOOL _loading = NO;
if ([_delegate respondsToSelector:@selector(egoRefreshTableHeaderDataSourceIsLoading:)]) {
_loading = [_delegate egoRefreshTableHeaderDataSourceIsLoading:self];
}
if (scrollView.contentOffset.y + (scrollView.frame.size.height) > scrollView.contentSize.height + RefreshViewHight && !_loading) {
if ([_delegate respondsToSelector:@selector(egoRefreshTableHeaderDidTriggerRefresh:)]) {
[_delegate egoRefreshTableHeaderDidTriggerRefresh:self];
}
[self setState:EGOOPullRefreshLoading];
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.2];
scrollView.contentInset = UIEdgeInsetsMake(0.0f, 0.0f, RefreshViewHight, 0.0f);
[UIView commitAnimations];
}
}
//当开发者页面页面刷新完毕调用此方法，[delegate egoRefreshScrollViewDataSourceDidFinishedLoading: scrollView];
- (void)egoRefreshScrollViewDataSourceDidFinishedLoading:(UIScrollView *)scrollView {
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:.3];
[scrollView setContentInset:UIEdgeInsetsMake(0.0f, 0.0f, 0.0f, 0.0f)];
[UIView commitAnimations];
[self setState:EGOOPullRefreshNormal];
}
#pragma mark -
#pragma mark Dealloc
- (void)dealloc {
_delegate=nil;
_activityView = nil;
_statusLabel = nil;
_arrowImage = nil;
_lastUpdatedLabel = nil;
[super dealloc];
}
@end
下面是调用类的代码
//
// RootViewController.m
// TableViewPull
//
// Created by Devin Doty on 10/16/09October16.
// Copyright enormego 2009. All rights reserved.
//
//修改：禚来强 email：zhuolaiqiang@gmail.com
#import "RootViewController.h"
@implementation RootViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self.tableView reloadData];
//self.tableView.contentInset = UIEdgeInsetsMake(200, 0, 320, 480);
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];
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
return YES;
}
#pragma mark -
#pragma mark UITableViewDataSource
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 10;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 4;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
// Configure the cell.
return cell;
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section{
return [NSString stringWithFormat:@"Section %i", section];
}
#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 Memory Management
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
}
- (void)viewDidUnload {
_refreshHeaderView=nil;
}
- (void)dealloc {
_refreshHeaderView = nil;
[super dealloc];
}
@end