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使用iOS控件UICollectionView生成可拖動(dòng)的桌面的實(shí)例

更新時(shí)間：2016年12月13日 09:51:39 作者：HelloWord杰少

本篇文章主要介紹了使用iOS控件UICollectionView生成可拖動(dòng)的桌面，具有一定的參考價(jià)值，有需要的可以了解一下。

一個(gè)App受歡迎的程度，一方面來(lái)源于它本身為用戶提供便捷的功能，另一方面則來(lái)源于它的UI。UI是用戶體驗(yàn)重要的組成部分，構(gòu)成UI的的元素恰恰離不開(kāi)那些看似獨(dú)立的控件。在開(kāi)發(fā)的過(guò)程中，大家對(duì)UITableView應(yīng)該很熟悉吧！確實(shí)UITableView在處理數(shù)據(jù)顯示方面有著很強(qiáng)大的功能，例如網(wǎng)紅們使用的微博，微信社交軟件的聊天界面等等，這種流式布局使用UITableView簡(jiǎn)直最合適不過(guò)了；但畢竟UITableView不是萬(wàn)能的，當(dāng)需要顯示橫縱向的數(shù)據(jù)時(shí)它就顯得捉襟見(jiàn)肘了，雖然這也難不倒我們程序猿但是何必要大費(fèi)周章的去定義復(fù)雜的cell呢！UICollectionView就是專門(mén)用來(lái)應(yīng)付這種布局的,使用UICollectionView可以給我們帶來(lái)以下幾點(diǎn)優(yōu)勢(shì)：1.可以高度的定制內(nèi)容展示的樣式 2.高效的管理大量的數(shù)據(jù)。

首先給大家看一下這個(gè)Demo的效果圖：

iOS設(shè)備不知道現(xiàn)在有沒(méi)有可以屏幕錄制的app,這樣我就可以把操作的動(dòng)作用gif圖片po上來(lái)了，大家如果有推薦可以告訴我哈！關(guān)于拖動(dòng)，長(zhǎng)按圖片后就可以將圖片拖到你想要的位置上，另外的圖片則會(huì)依次排序，很順暢的體驗(yàn)。

在使用UICollectionView的時(shí)后，我們的類需要實(shí)現(xiàn)這些協(xié)議:UICollectionViewDataSource,UICollectionViewDelegateFlowLayout,

UICollectionViewDelegate,UIGestureRecognizerDelegate。

UICollectionViewDataSource：和我們?cè)赨ITableView中所需要實(shí)現(xiàn)的UITableViewDataSource是一個(gè)道理，它里面包括以下這些API：

@protocol UICollectionViewDataSource <NSObject> 
@required 
 
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section; 
 
// The cell that is returned must be retrieved from a call to -dequeueReusableCellWithReuseIdentifier:forIndexPath: 
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath; 
 
@optional 
 
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView; 
 
// The view that is returned must be retrieved from a call to -dequeueReusableSupplementaryViewOfKind:withReuseIdentifier:forIndexPath: 
- (UICollectionReusableView *)collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath; 
 
- (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath:(NSIndexPath *)indexPath NS_AVAILABLE_IOS(9_0); 
- (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath*)destinationIndexPath NS_AVAILABLE_IOS(9_0); 
 
@end

UICollectionViewDelegateFlowLayout：UICollectionViewFlowLayout是一個(gè)專門(mén)用來(lái)管理collectionView布局的類,可以通過(guò)實(shí)現(xiàn)以下函數(shù)來(lái)調(diào)整我們界面的樣式：

@protocol UICollectionViewDelegateFlowLayout <UICollectionViewDelegate> 
@optional 
 
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath; 
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section; 
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section; 
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section; 
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForHeaderInSection:(NSInteger)section; 
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout referenceSizeForFooterInSection:(NSInteger)section; 
 
@end

UICollectionViewDelegate：和UITableViewDelegate一樣，這里就把它協(xié)議里面的的函數(shù)po出來(lái)了,通過(guò)重寫(xiě)里面的函數(shù)，我們可以實(shí)現(xiàn)cell的點(diǎn)擊與拖動(dòng)。

UIGestureRecognizerDelegate：由于我們還有一個(gè)拖動(dòng)的功能，所以需要實(shí)現(xiàn)用戶手勢(shì)的協(xié)議。

好了，基礎(chǔ)的概念講了，現(xiàn)在我們就開(kāi)始動(dòng)手實(shí)現(xiàn)他吧！老樣子直接看源碼：

- (void)viewDidLoad { 
  [super viewDidLoad]; 
  // Do any additional setup after loading the view, typically from a nib. 
   
  //設(shè)置背景色 
  [self.view setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"back.jpg"]]]; 
  //設(shè)置數(shù)據(jù)源 
  self.dataSource = [[NSMutableArray alloc] initWithObjects: 
            @"1.png",@"2.png",@"3.png", @"4.png", @"5.png", @"6.png", @"7.png", @"8.png", @"9.png", @"10.png", @"11.jpg", @"12.JPG", 
            @"13.JPG", @"14.jpg", @"15.JPG", @"16.png", @"17.png", @"18.png", @"19.png", @"20.png", nil nil]; 
  //初始化布局 
  self.flow = [[UICollectionViewFlowLayout alloc] init]; 
  self.collect = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:self.flow]; 
  [self.collect setBackgroundColor:[UIColor clearColor]]; 
   
  //注冊(cè)cell 這一步必須要實(shí)現(xiàn) 
  [self.collect registerClass:[CustomCollectionCell class] forCellWithReuseIdentifier:@"CustomCell"]; 
   
  self.collect.delegate = self; 
  self.collect.dataSource = self; 
   
  [self.collect setFrame:self.view.bounds]; 
   
  //添加長(zhǎng)按手勢(shì) 
  self.longPressGestureRecognizer = [[UILongPressGestureRecognizer alloc] init]; 
  [self.longPressGestureRecognizer addTarget:self action:@selector(handleLongPressRecognizer:)]; 
  [self.collect addGestureRecognizer:self.longPressGestureRecognizer]; 
   
  [self.view addSubview:self.collect]; 
}

在viewDidLoad函數(shù)中，初始化了一個(gè)UICollectionViewFlowLayout布局，并且需要配合UICollectionView來(lái)使用，兩者加一起來(lái)使用才能“完美”，想比UITableView 中Cell使用的不同，在UICollectionView中必須先對(duì)Cell進(jìn)行注冊(cè)(RegisterClass)，不然會(huì)在運(yùn)行過(guò)程中報(bào)錯(cuò)。如何使排列的圖片可以拖動(dòng)呢，在這里我為UICollectionView添加了一個(gè)長(zhǎng)按手勢(shì)UILongPressGestureRecognizer。當(dāng)我們長(zhǎng)按時(shí)會(huì)觸發(fā)handleLongPressRecognizer，代碼如下：

- (void)handleLongPressRecognizer:(UILongPressGestureRecognizer *)gesture{ 
  switch (gesture.state) { 
    case UIGestureRecognizerStateBegan:{ 
      NSIndexPath *path = [self.collect indexPathForItemAtPoint:[gesture locationInView:gesture.view]]; 
      if(path == nil){ 
        break; 
      } 
       
      [self.collect beginInteractiveMovementForItemAtIndexPath:path]; 
    } 
      break; 
    case UIGestureRecognizerStateChanged: 
      [self.collect updateInteractiveMovementTargetPosition:[gesture locationInView:gesture.view]]; 
      break; 
    case UIGestureRecognizerStateEnded: 
      [self.collect endInteractiveMovement]; 
      break; 
    default: 
      [self.collect cancelInteractiveMovement]; 
      break; 
  } 
}

好看的界面才能抓住用戶的心，這里我自定義了Cell繼承自UICollectionViewCell，cell中展示的圖片會(huì)根據(jù)自身圖片的大小進(jìn)行按比例縮放，這樣我們的桌面看上去就會(huì)有橫版圖片與豎版圖片，如果不自定義的話就都是方方正正的九宮格，還是花點(diǎn)心思自定義一下顯示效果吧！CustomCollectionCell的的代碼如下：

#import "CustomCollectionCell.h" 
 
@implementation CustomCollectionCell 
@synthesize imageV = _imageV; 
@synthesize labelV = _labelV; 
@synthesize boundView = _boundView; 
 
- (id)initWithFrame:(CGRect) frame{ 
  self = [super initWithFrame:frame]; 
  //init attributes 
  if(self){ 
    [self setBackgroundColor:[UIColor clearColor]]; 
    self.imageV = [[UIImageView alloc] initWithFrame:CGRectZero]; 
    self.labelV = [[UILabel alloc] initWithFrame:CGRectZero]; 
    self.boundView = [[UIView alloc] initWithFrame:CGRectZero]; 
    [self.boundView setBackgroundColor:[UIColor whiteColor]]; 
    [self.boundView addSubview:self.imageV]; 
    [self addSubview:self.boundView]; 
    [self addSubview:self.labelV]; 
  } 
   
  return self; 
} 
 
- (void)setImageWithText:(UIImage *)image text:(NSString *)text{ 
  if(!image){ 
    return; 
  } 
   
  CGFloat imgWidth = image.size.width; 
  CGFloat imgHeight = image.size.height; 
  CGFloat iconWidth = 0.0; 
  CGFloat iconHeight = 0.0; 
   
  if(imgWidth > imgHeight){ 
    iconHeight = roundf(((self.frame.size.width - 16)*imgHeight)/imgWidth); 
    iconWidth = self.frame.size.width - 16; 
    [self.boundView setFrame:CGRectMake(0, self.frame.size.height - iconHeight - 16, iconWidth + 16, iconHeight + 16)]; 
    [self.imageV setFrame:CGRectMake(8, 8, iconWidth, iconHeight)]; 
  }else{ 
    iconWidth = roundf(((self.frame.size.width - 16) *imgWidth)/imgHeight); 
    iconHeight = self.frame.size.height - 16; 
    [self.boundView setFrame:CGRectMake(roundf((self.frame.size.width - iconWidth)/2), 0, iconWidth + 16, iconHeight + 16)]; 
    [self.imageV setFrame:CGRectMake(8, 8, iconWidth, iconHeight)]; 
  } 
   
  [self.imageV setImage:image]; 
} 
 
@end

以上這些就是構(gòu)成該Demo的重要組成部分了，UICollectionView還有很多的要素在這里面沒(méi)有講到，往后我還會(huì)再研究這個(gè)控件更加高級(jí)的的使用，本篇就好比是餐前的開(kāi)胃小菜吧，希望大家喜歡。附上這個(gè)例子的源碼：

@implementation ViewController 
@synthesize dataSource = _dataSource; 
@synthesize longPressGestureRecognizer = _longPressGestureRecognizer; 
@synthesize flow = _flow; 
@synthesize collect = _collect; 
 
- (void)viewDidLoad { 
  [super viewDidLoad]; 
  // Do any additional setup after loading the view, typically from a nib. 
   
  //設(shè)置背景色 
  [self.view setBackgroundColor:[UIColor colorWithPatternImage:[UIImage imageNamed:@"back.jpg"]]]; 
  //設(shè)置數(shù)據(jù)源 
  self.dataSource = [[NSMutableArray alloc] initWithObjects: 
            @"1.png",@"2.png",@"3.png", @"4.png", @"5.png", @"6.png", @"7.png", @"8.png", @"9.png", @"10.png", @"11.jpg", @"12.JPG", 
            @"13.JPG", @"14.jpg", @"15.JPG", @"16.png", @"17.png", @"18.png", @"19.png", @"20.png", nil nil]; 
  //初始化布局 
  self.flow = [[UICollectionViewFlowLayout alloc] init]; 
  self.collect = [[UICollectionView alloc] initWithFrame:CGRectZero collectionViewLayout:self.flow]; 
  [self.collect setBackgroundColor:[UIColor clearColor]]; 
   
  //注冊(cè)cell 這一步必須要實(shí)現(xiàn) 
  [self.collect registerClass:[CustomCollectionCell class] forCellWithReuseIdentifier:@"CustomCell"]; 
   
  self.collect.delegate = self; 
  self.collect.dataSource = self; 
   
  [self.collect setFrame:self.view.bounds]; 
   
  //添加長(zhǎng)按手勢(shì) 
  self.longPressGestureRecognizer = [[UILongPressGestureRecognizer alloc] init]; 
  [self.longPressGestureRecognizer addTarget:self action:@selector(handleLongPressRecognizer:)]; 
  [self.collect addGestureRecognizer:self.longPressGestureRecognizer]; 
   
  [self.view addSubview:self.collect]; 
} 
 
- (void)didReceiveMemoryWarning { 
  [super didReceiveMemoryWarning]; 
  // Dispose of any resources that can be recreated. 
} 
 
- (void)handleLongPressRecognizer:(UILongPressGestureRecognizer *)gesture{ 
  switch (gesture.state) { 
    case UIGestureRecognizerStateBegan:{ 
      NSIndexPath *path = [self.collect indexPathForItemAtPoint:[gesture locationInView:gesture.view]]; 
      if(path == nil){ 
        break; 
      } 
       
      [self.collect beginInteractiveMovementForItemAtIndexPath:path]; 
    } 
      break; 
    case UIGestureRecognizerStateChanged: 
      [self.collect updateInteractiveMovementTargetPosition:[gesture locationInView:gesture.view]]; 
      break; 
    case UIGestureRecognizerStateEnded: 
      [self.collect endInteractiveMovement]; 
      break; 
    default: 
      [self.collect cancelInteractiveMovement]; 
      break; 
  } 
} 
 
#pragma mark UICollectionViewDataSource 
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section{ 
  return self.dataSource.count; 
} 
 
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView{ 
  return 1; 
} 
 
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath{ 
  CustomCollectionCell * cell = (CustomCollectionCell *)[collectionView dequeueReusableCellWithReuseIdentifier:@"CustomCell" forIndexPath:indexPath]; 
  UIImage *image = [UIImage imageNamed:[self.dataSource objectAtIndex:indexPath.row]]; 
  [cell setImageWithText:image text:@""]; 
   
  return cell; 
} 
 
- (BOOL)collectionView:(UICollectionView *)collectionView canMoveItemAtIndexPath:(NSIndexPath *)indexPath{ 
  return YES; 
} 
 
- (void)collectionView:(UICollectionView *)collectionView moveItemAtIndexPath:(NSIndexPath *)sourceIndexPath toIndexPath:(NSIndexPath*)destinationIndexPath{ 
   
  id item = [self.dataSource objectAtIndex:sourceIndexPath.item]; 
  [self.dataSource removeObject:item]; 
   
  [self.dataSource insertObject:item atIndex:destinationIndexPath.item]; 
} 
 
#pragma mark UICollectionViewDelegate 
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath{ 
  TestViewController *test = [[TestViewController alloc] initWithNibName:@"TestViewController" bundle:nil]; 
  NSString *imageName = [self.dataSource objectAtIndex:indexPath.row]; 
  test.imageName = imageName; 
   
  [self.navigationController pushViewController:test animated:YES]; 
} 
 
- (BOOL)collectionView:(UICollectionView *)collectionView shouldHighlightItemAtIndexPath:(NSIndexPath *)indexPath{ 
  return YES; 
} 
 
//選中放大效果 
- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath{ 
//  CustomCollectionCell * cell = (CustomCollectionCell *)[collectionView cellForItemAtIndexPath:indexPath]; 
//   
//  [UIView animateWithDuration:1 animations:^{ 
//    cell.transform = CGAffineTransformMakeScale(2.0f, 2.0f); 
//  }]; 
} 
 
//縮小效果 
- (void)collectionView:(UICollectionView *)collectionView didUnhighlightItemAtIndexPath:(NSIndexPath *)indexPath{ 
//  CustomCollectionCell * cell = (CustomCollectionCell *)[collectionView cellForItemAtIndexPath:indexPath]; 
//   
//  [UIView animateWithDuration:1 animations:^{ 
//    cell.transform = CGAffineTransformMakeScale(1.0f, 1.0f); 
//  }]; 
} 
 
 
#pragma mark UICollectionViewDelegateFlowLayout 
- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath{ 
   
  return CGSizeMake(100, 100); 
} 
 
/* 
 * 上左下右間距 
 */ 
- (UIEdgeInsets)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout insetForSectionAtIndex:(NSInteger)section{ 
   
  return UIEdgeInsetsMake(15, 15, 15, 15); 
} 
 
/* 
 * item space 
 */ 
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumInteritemSpacingForSectionAtIndex:(NSInteger)section{ 
   
  return 8; 
} 
 
/* 
 * 行距 20 
 */ 
- (CGFloat)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout*)collectionViewLayout minimumLineSpacingForSectionAtIndex:(NSInteger)section{ 
   
  return 10; 
}

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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