【移動(dòng)應(yīng)用開發(fā)技術(shù)】iOS中怎么實(shí)現(xiàn)一個(gè)下拉、上拉刷新控件

【移動(dòng)應(yīng)用開發(fā)技術(shù)】iOS中怎么實(shí)現(xiàn)一個(gè)下拉、上拉刷新控件

iOS中怎么實(shí)現(xiàn)一個(gè)下拉、上拉刷新控件，相信很多沒有經(jīng)驗(yàn)的人對(duì)此束手無策，為此本文總結(jié)了問題出現(xiàn)的原因和解決方法，通過這篇文章希望你能解決這個(gè)問題?？刂破鱒iewController：#import

<UIKit/UIKit.h>

@interface

ViewController

:

UIViewController

@end

/***

分割線

***/

#import

"ViewController.h"

#import

"HWRefresh.h"

@interface

ViewController

()<UITableViewDataSource,

UITableViewDelegate>

@property

(nonatomic,

strong)

NSMutableArray

*array;

@property

(nonatomic,

strong)

UITableView

*tableView;

@property

(nonatomic,

assign)

NSInteger

page;

@end

@implementation

ViewController

-

(NSMutableArray

*)array

{

if

(!_array)

{

_array

=

[NSMutableArray

array];

}

return

_array;

}

-

(void)viewDidLoad

{

[super

viewDidLoad];

self.view.backgroundColor

=

[UIColor

blackColor];

self.page

=

1;

//模擬獲取信息

[self

getInfo];

//創(chuàng)建控件

[self

creatControl];

//添加頭部刷新

[self

addHeaderRefresh];

//添加尾部刷新

[self

addFooterRefresh];

}

-

(void)getInfo

{

NSArray

*array

=

@[@"iOS

HERO博客",

@"iOS

HERO博客",

@"iOS

HERO博客",

@"iOS

HERO博客",

@"/hero_wqb"];

dispatch_after(dispatch_time(DISPATCH_TIME_NOW,

(int64_t)(2.0f

*

NSEC_PER_SEC)),

dispatch_get_main_queue(),

^{

if

(self.page

==

1)

{

self.array

=

[NSMutableArray

arrayWithArray:array];

}else{

[self.array

addObjectsFromArray:array];

}

[_tableView

reloadData];

[_tableView

headerEndRefreshing];

[_tableView

footerEndRefreshing];

NSLog(@"已經(jīng)刷新好了");

});

}

-

(void)creatControl

{

//列表視圖

_tableView

=

[[UITableView

alloc]

initWithFrame:CGRectMake(20,

64,

[[UIScreen

mainScreen]

bounds].size.width

-

100,

[[UIScreen

mainScreen]

bounds].size.height

-

164)

style:UITableViewStylePlain];

_tableView.dataSource

=

self;

_tableView.delegate

=

self;

[self.view

addSubview:_tableView];

}

-

(void)addHeaderRefresh

{

__weak

typeof(self)

weakSelf

=

self;

[_tableView

addHeaderRefreshWithCallback:^{

__strong

typeof(weakSelf)

strongSelf

=

weakSelf;

strongSelf.page

=

1;

[strongSelf

getInfo];

}];

}

-

(void)addFooterRefresh

{

__weak

typeof(self)

weakSelf

=

self;

[_tableView

addFooterRefreshWithCallback:^{

__strong

typeof(weakSelf)

strongSelf

=

weakSelf;

strongSelf.page

++;

[strongSelf

getInfo];

}];

}

#pragma

mark

-

UITableViewDataSource

-

(NSInteger)tableView:(UITableView

*)tableView

numberOfRowsInSection:(NSInteger)section

{

return

self.array.count;

}

-

(UITableViewCell

*)tableView:(UITableView

*)tableView

cellForRowAtIndexPath:(NSIndexPath

*)indexPath

{

static

NSString

*identifier

=

@"refreshTest";

UITableViewCell

*cell

=

[tableView

dequeueReusableCellWithIdentifier:identifier];

if

(!cell)

{

cell

=

[[UITableViewCell

alloc]

initWithStyle:UITableViewCellStyleDefault

reuseIdentifier:identifier];

}

cell.textLabel.text

=

[_array[indexPath.row]

stringByAppendingString:[NSString

stringWithFormat:@"_%ld",

indexPath.row]];

return

cell;

}

-

(void)scrollViewDidScroll:(UIScrollView

*)scrollView

{

//滑動(dòng)到底部自動(dòng)刷新

if

(_tableView.contentSize.height

>

_tableView.frame.size.height

&&

_tableView.contentOffset.y

+

_tableView.frame.size.height

>

_tableView.contentSize.height

-

40

&&

_page

<

50)

{

[_tableView

footerBeginRefreshing];

}

}

@end刷新基類HWRefreshBaseView：#import

<UIKit/UIKit.h>

#define

HWRefreshContentOffset

@"contentOffset"

typedef

enum

{

HWRefreshStateNormal

=

0,

//普通狀態(tài)

HWRefreshStatePulling,

//釋放即可刷新的狀態(tài)

HWRefreshStateRefreshing,

//正在刷新中的狀態(tài)

}

HWRefreshState;

@interface

HWRefreshBaseView

:

UIView

@property

(nonatomic,

weak)

UIScrollView

*scrollView;

@property

(nonatomic,

copy)

NSString

*pullToRefreshText;

@property

(nonatomic,

copy)

NSString

*releaseToRefreshText;

@property

(nonatomic,

copy)

NSString

*refreshingText;

@property

(nonatomic,

copy)

void

(^refreshingCallback)();

@property

(nonatomic,

assign)

HWRefreshState

state;

@property

(nonatomic,

assign)

UIEdgeInsets

scrollViewOriginalInset;

-

(void)beginRefreshing;

-

(void)endRefreshing;

@end

/***

分割線

***/

#import

"HWRefreshBaseView.h"

#define

KHWRefreshViewHeight

44.0f

#define

KImageW

30.0f

#define

KLabelW

100.0f

@interface

HWRefreshBaseView

()

@property

(nonatomic,

weak)

UILabel

*rLabel;

@property

(nonatomic,

weak)

UIImageView

*rImageView;

@end

@implementation

HWRefreshBaseView

-

(instancetype)initWithFrame:(CGRect)frame

{

frame.size.height

=

KHWRefreshViewHeight;

if

(self

=

[super

initWithFrame:frame])

{

CGFloat

imageH

=

30.f;

CGFloat

labelH

=

20.f;

CGFloat

imageX

=

([UIScreen

mainScreen].bounds.size.width

-

KImageW

-

KLabelW)

*

0.5;

CGFloat

imageY

=

(KHWRefreshViewHeight

-

imageH)

*

0.5;

CGFloat

labelY

=

(KHWRefreshViewHeight

-

labelH)

*

0.5;

//圖片

UIImageView

*rImageView

=

[[UIImageView

alloc]

initWithFrame:CGRectMake(imageX,

imageY,

KImageW,

imageH)];

rImageView.image

=

[UIImage

imageNamed:@"refreshing.jpg"];

[self

addSubview:rImageView];

self.rImageView

=

rImageView;

//標(biāo)簽

UILabel

*rLabel

=

[[UILabel

alloc]

initWithFrame:CGRectMake(CGRectGetMaxX(rImageView.frame),

labelY,

KLabelW,

labelH)];

rLabel.text

=

self.pullToRefreshText;

rLabel.font

=

[UIFont

systemFontOfSize:14.0f];

rLabel.textAlignment

=

NSTextAlignmentCenter;

[self

addSubview:rLabel];

self.rLabel

=

rLabel;

}

return

self;

}

-

(void)willMoveToSuperview:(UIView

*)newSuperview

{

[super

willMoveToSuperview:newSuperview];

//舊的父控件

[self.superview

removeObserver:self

forKeyPath:HWRefreshContentOffset

context:nil];

//新的父控件

if

(newSuperview)

{

[newSuperview

addObserver:self

forKeyPath:HWRefreshContentOffset

options:NSKeyValueObservingOptionNew

context:nil];

//記錄UIScrollView

_scrollView

=

(UIScrollView

*)newSuperview;

//記錄UIScrollView最開始的contentInset

_scrollViewOriginalInset

=

_scrollView.contentInset;

}

//居中顯示圖片、提示信息

CGRect

temFrame

=

_rImageView.frame;

temFrame.origin.x

=

(newSuperview.frame.size.width

-

KImageW

-

KLabelW)

*

0.5;

_rImageView.frame

=

temFrame;

CGRect

tf

=

_rLabel.frame;

tf.origin.x

=

CGRectGetMaxX(_rImageView.frame);

_rLabel.frame

=

tf;

}

-

(void)setPullToRefreshText:(NSString

*)pullToRefreshText

{

_pullToRefreshText

=

pullToRefreshText;

self.rLabel.text

=

pullToRefreshText;

}

-

(void)setState:(HWRefreshState)state

{

if

(_state

==

state)

return;

switch

(state)

{

case

HWRefreshStateNormal:

{

[self

stopAnimating];

self.rLabel.text

=

self.pullToRefreshText;

break;

}

case

HWRefreshStatePulling:

{

self.rLabel.text

=

self.releaseToRefreshText;

break;

}

case

HWRefreshStateRefreshing:

{

[self

startAnimating];

self.rLabel.text

=

self.refreshingText;

if

(self.refreshingCallback)

self.refreshingCallback();

break;

}

default:

break;

}

_state

=

state;

}

//開始刷新

-

(void)beginRefreshing

{

self.state

=

HWRefreshStateRefreshing;

}

//結(jié)束刷新

-

(void)endRefreshing

{

self.state

=

HWRefreshStateNormal;

}

//開始動(dòng)畫

-

(void)startAnimating

{

NSMutableArray

*array

=

[NSMutableArray

array];

for

(int

i

=

0;

i

<

2;

i++)

{

NSString

*imageName

=

[NSString

stringWithFormat:@"refreshing%02d.jpg",

i

+

1];

UIImage

*image

=

[UIImage

imageNamed:imageName];

[array

addObject:image];

}

[_rImageView

setAnimationImages:array];

[_rImageView

setAnimationDuration:0.3f];

[_rImageView

startAnimating];

}

//結(jié)束動(dòng)畫

-

(void)stopAnimating

{

if

(_rImageView.isAnimating)

{

[_rImageView

stopAnimating];

[_rImageView

performSelector:@selector(setAnimationImages:)

withObject:nil

afterDelay:0];

}

}

@end頭部刷新HWRefreshHeader：#import

"HWRefreshBaseView.h"

@interface

HWRefreshHeader

:

HWRefreshBaseView

+

(instancetype)header;

@end

/***

分割線

***/

#import

"HWRefreshHeader.h"

@implementation

HWRefreshHeader

+

(instancetype)header

{

return

[[HWRefreshHeader

alloc]

init];

}

-

(instancetype)initWithFrame:(CGRect)frame

{

if

(self

=

[super

initWithFrame:frame])

{

self.pullToRefreshText

=

@"下拉即可刷新";

self.releaseToRefreshText

=

@"釋放即可刷新";

self.refreshingText

=

@"刷新中...";

}

return

self;

}

-

(void)willMoveToSuperview:(UIView

*)newSuperview

{

[super

willMoveToSuperview:newSuperview];

//設(shè)置自己的位置和尺寸

CGRect

frame

=

self.frame;

frame.origin.y

=

-

self.frame.size.height;

self.frame

=

frame;

}

-

(void)observeValueForKeyPath:(NSString

*)keyPath

ofObject:(id)object

change:(NSDictionary

*)change

context:(void

*)context

{

//不能跟用戶交互或正在刷新就直接返回

if

(!self.userInteractionEnabled

||

self.alpha

<=

0.01

||

self.hidden

||

self.state

==

HWRefreshStateRefreshing)

return;

//根據(jù)偏移量設(shè)置相應(yīng)狀態(tài)

if

([keyPath

isEqualToString:HWRefreshContentOffset])

{

[self

setStateWithContentOffset];

}

}

-

(void)setStateWithContentOffset

{

//當(dāng)前的contentOffset

CGFloat

currentOffsetY

=

self.scrollView.contentOffset.y;

//頭部控件剛好出現(xiàn)的offsetY

CGFloat

happenOffsetY

=

-

self.scrollViewOriginalInset.top;

//如果是向上滾動(dòng)到看不見頭部控件，直接返回

if

(currentOffsetY

>=

happenOffsetY)

return;

//滑動(dòng)時(shí)

if

(self.scrollView.isDragging)

{

//普通狀態(tài)和即將刷新狀態(tài)的臨界點(diǎn)

CGFloat

normalTopullingOffsetY

=

happenOffsetY

-

self.frame.size.height;

//轉(zhuǎn)為即將刷新狀態(tài)

if

(self.state

==

HWRefreshStateNormal

&&

currentOffsetY

<

normalTopullingOffsetY)

{

self.state

=

HWRefreshStatePulling;

//轉(zhuǎn)為普通狀態(tài)

}else

if

(self.state

==

HWRefreshStatePulling

&&

currentOffsetY

>=

normalTopullingOffsetY)

{

self.state

=

HWRefreshStateNormal;

}

//松手時(shí)，如果是松開就可以進(jìn)行刷新的狀態(tài)，則進(jìn)行刷新

}else

if

(self.state

==

HWRefreshStatePulling)

{

self.state

=

HWRefreshStateRefreshing;

}

}

-

(void)setState:(HWRefreshState)state

{

//若狀態(tài)未改變，直接返回

if

(self.state

==

state)

return;

//保存舊狀態(tài)

HWRefreshState

oldState

=

self.state;

//調(diào)用父類方法

[super

setState:state];

switch

(state)

{

case

HWRefreshStateNormal:

{

//如果由刷新狀態(tài)返回到普通狀態(tài)

if

(oldState

==

HWRefreshStateRefreshing)

{

[UIView

animateWithDuration:0.25f

animations:^{

UIEdgeInsets

inset

=

self.scrollView.contentInset;

inset.top

-=

self.frame.size.height;

self.scrollView.contentInset

=

inset;

}];

}

break;

}

case

HWRefreshStatePulling:

{

break;

}

case

HWRefreshStateRefreshing:

{

//執(zhí)行動(dòng)畫

[UIView

animateWithDuration:0.25f

animations:^{

CGFloat

top

=

self.scrollViewOriginalInset.top

+

self.frame.size.height;

//增加滾動(dòng)區(qū)域

UIEdgeInsets

inset

=

self.scrollView.contentInset;

inset.top

=

top;

self.scrollView.contentInset

=

inset;

//設(shè)置滾動(dòng)位置

CGPoint

offset

=

self.scrollView.contentOffset;

offset.y

=

-

top;

self.scrollView.contentOffset

=

offset;

}];

break;

}

default:

break;

}

self.state

=

state;

}

@end分類UIScrollView+HWRefresh：#import

<UIKit/UIKit.h>

@interface

UIScrollView

(HWRefresh)

//添加下拉刷新回調(diào)

-

(void)addHeaderRefreshWithCallback:(void

(^)())callback;

//讓下拉刷新控件停止刷新

-

(void)headerEndRefreshing;

//添加上拉刷新回調(diào)

-

(void)addFooterRefreshWithCallback:(void

(^)())callback;

//讓上拉刷新控件開始刷新

-

(void)footerBeginRefreshing;

//讓上拉刷新控件停止刷新

-

(void)footerEndRefreshing;

@end

/***

分割線

***/

#import

"UIScrollView+HWRefresh.h"

#import

"HWRefreshHeader.h"

#import

"HWRefreshFooter.h"

#import

<objc/runtime.h>

@interface

UIScrollView

()

@property

(nonatomic,

weak)

HWRefreshHeader

*header;

@property

(weak,

nonatomic)

HWRefreshFooter

*footer;

@end

@implementation

UIScrollView

(HWRefresh)

static

char

HWRefreshHeaderKey;

static

char

HWRefreshFooterKey;

-

(void)setHeader:(HWRefreshHeader

*)header

{

[self

willChangeValueForKey:@"HWRefreshHeaderKey"];

objc_s