优化部分功能

对预加载的图片的方式进行了优化和完善

test.xcodeproj/project.pbxproj

@@ -542,6 +542,7 @@
 			baseConfigurationReference = 52839D449824474097575972 /* Pods-test.debug.xcconfig */;
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				CODE_SIGN_IDENTITY = "";
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
 				CODE_SIGN_STYLE = Manual;
 				DEVELOPMENT_TEAM = "";
@@ -560,6 +561,7 @@
 			baseConfigurationReference = 7258DD35A57A1219D711F5E6 /* Pods-test.release.xcconfig */;
 			buildSettings = {
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				CODE_SIGN_IDENTITY = "";
 				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
 				CODE_SIGN_STYLE = Manual;
 				DEVELOPMENT_TEAM = "";
@@ -568,6 +570,7 @@
 				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
 				PRODUCT_BUNDLE_IDENTIFIER = com.vcyber.test;
 				PRODUCT_NAME = "$(TARGET_NAME)";
+				PROVISIONING_PROFILE = "";
 				PROVISIONING_PROFILE_SPECIFIER = "";
 			};
 			name = Release;

test/Class/style3/LBStyle3VC.m

@@ -66,6 +66,7 @@ - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(N
         [[LBPhotoBrowserManager defaultManager] addPlaceholdImageCallBackBlock:^UIImage *(NSIndexPath *indexPath) {
             return [UIImage imageNamed:@"placehold.jpeg"];
         }];
+
     }];
     return cell;
 }

test/LBPhotoBrowser/LBPhotoBrowserManager.h

@@ -76,7 +76,6 @@
 // 每张正在加载的图片的站位图的大小
 @property (nonatomic , copy ,readonly)CGSize (^placeholdImageSizeBlock)(UIImage *Image,NSIndexPath *indexpath);
 
-
 /**
  开启这个选项后 在加载gif的时候 会大大的降低内存.与YYImage对gif的内存优化思路一样 default is NO
  每次LBPhotoBrowser -> did dismiss(消失)的时候,LBPhotoBrowserManager 会将 lowGifMemory 置为NO,

test/LBPhotoBrowser/LBPhotoBrowserView.h

@@ -31,7 +31,6 @@
 
 @property (nonatomic , assign)BOOL isShowing;
 @property (nonatomic , assign)BOOL showPopAnimation;
-@property (nonatomic , assign)BOOL shouldCancel;
 @property (nonatomic , assign)int index;
 
 @property (nonatomic , copy)void (^loadImageCompletedBlock)(LBScrollViewStatusModel *loadModel,UIImage *image, NSData *data, NSError *  error, BOOL finished, NSURL *imageURL);

test/LBPhotoBrowser/LBPhotoBrowserView.m

@@ -49,10 +49,12 @@ @interface LBPhotoBrowserView ()<UICollectionViewDelegate,UICollectionViewDataSo
 
 @property (nonatomic , assign)CGFloat zoomScale;
 
-@property (nonatomic , assign)BOOL stopPreloading;
-
 @property (nonatomic , assign)CGPoint startCenter;
 
+@property (nonatomic , strong)NSMutableDictionary *loadingImageModelDic;
+@property (nonatomic , strong)NSMutableDictionary *preloadingModelDic;
+//GCD中的对象在6.0之前是不参与ARC的，而6.0之后 在ARC下使用GCD也不用关心释放问题
+@property (strong, nonatomic) dispatch_queue_t preloadingQueue;
 
 @end
 
@@ -79,15 +81,16 @@ - (void)loadImage {
     if (self.opreation) {
         return;
     }
+    //Code=-999 "已取消"
     self.opreation = [[SDWebImageManager sharedManager] loadImageWithURL:self.url options:0 progress:^(NSInteger receivedSize, NSInteger expectedSize, NSURL * _Nullable targetURL) {
-
-        //LBPhotoBrowserLog(@"LBScrollViewStatusModel:( %d ) line %d log: %d -- %d",self.index,__LINE__,(int)receivedSize ,(int)expectedSize);
+        
+//        LBPhotoBrowserLog(@"LBScrollViewStatusModel:( %d ) line %d log: %d -- %d",self.index,__LINE__,(int)receivedSize ,(int)expectedSize);
     } completed:^(UIImage * _Nullable image, NSData * _Nullable data, NSError * _Nullable error, SDImageCacheType cacheType, BOOL finished, NSURL * _Nullable imageURL) {
        __block UIImage *downloadedImage = image;
         dispatch_async(dispatch_get_main_queue(), ^{
             wself.opreation = nil;
             if (wself.loadImageCompletedBlock) {
-                wself.loadImageCompletedBlock(self, downloadedImage, data, error, finished, imageURL);
+                wself.loadImageCompletedBlock(wself, downloadedImage, data, error, finished, imageURL);
             }else {
                 if (error) {
                     downloadedImage = [LBPhotoBrowserManager defaultManager].errorImage;
@@ -154,6 +157,7 @@ @implementation LBPhotoBrowserView
 
 - (void)dealloc {
     [[NSNotificationCenter defaultCenter]removeObserver:self];
+    SDDispatchQueueRelease(_preloadingQueue);
 }
 
 - (NSMutableArray *)models {
@@ -162,6 +166,19 @@ - (NSMutableArray *)models {
     }
     return _models;
 }
+- (NSMutableDictionary *)preloadingModelDic {
+    if (!_preloadingModelDic) {
+        _preloadingModelDic = [[NSMutableDictionary alloc]init];
+    }
+    return _preloadingModelDic;
+}
+
+- (NSMutableDictionary *)loadingImageModelDic {
+    if (!_loadingImageModelDic) {
+        _loadingImageModelDic = [[NSMutableDictionary alloc]init];
+    }
+    return _loadingImageModelDic;
+}
 
 - (UIPageControl *)pageControl {
     if (!_pageControl) {
@@ -215,8 +232,8 @@ - (instancetype)initWithFrame:(CGRect)frame
         UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(didPan:)];
         [self addGestureRecognizer:pan];
         [LBPhotoBrowserManager defaultManager].currentCollectionView = self.collectionView;
+        _preloadingQueue = dispatch_queue_create("lb.photoBrowser", DISPATCH_QUEUE_SERIAL);
         _isShowing = NO;
-        _stopPreloading = NO;
     }
     return self;
 }
@@ -288,6 +305,7 @@ - (void)cancelFromCell:(LBPhotoCollectionViewCell *)cell {
 }
 
 #pragma mark - 监听通知
+
 - (void)removePageControl {
     [UIView animateWithDuration:0.25 animations:^{
         self.pageControl.alpha = 0;
@@ -297,7 +315,7 @@ - (void)removePageControl {
     if (![LBPhotoBrowserManager defaultManager].needPreloading) {
         return;
     }
-    [self.models enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
+    [self.loadingImageModelDic.allValues enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
         LBScrollViewStatusModel *model = (LBScrollViewStatusModel *)obj;
         if (model.opreation) {
             [model.opreation cancel];
@@ -366,7 +384,7 @@ - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cell
 }
 #pragma mark - 代理方法
 
-// 新版的SDWebImage不知支持Gif 故采用了老版Gif的方式 但是这样加载太多Gif内存容易升高 在收到内存警告的时候 可以通过这个来清理内存 [[SDImageCache sharedImageCache] setValue:nil forKey:@"memCache"]
+// 新版的SDWebImage不知支持Gif 故采用了老版Gif的方式 但是这样加载太多Gif内存容易升高 在收到内存警告的时候 可以通过这个来清理内存 [[SDImageCache sharedImageCache] clearMemory];
 
 - (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
     return CGSizeMake(SCREEN_WIDTH + itemSpace, SCREEN_HEIGHT);
@@ -395,42 +413,37 @@ - (void)collectionView:(UICollectionView *)collectionView willDisplayCell:(UICol
 
     if (![LBPhotoBrowserManager defaultManager].needPreloading) return;
 
-    if (self.stopPreloading) return;
-
-    // 异步线程加载数据
-    dispatch_async(dispatch_get_global_queue(0, 0), ^{
-
-        for (LBScrollViewStatusModel *obj in wself.models) {
-            obj.shouldCancel = YES;
-        }
-
+    dispatch_async(wself.preloadingQueue, ^{
         int leftCellIndex = model.index - 1 >= 0 ?model.index - 1:0;
         int rightCellIndex = model.index + 1 < wself.models.count? model.index + 1 : (int)wself.models.count -1;
-
+        //wself.loadingImageModels 新计算出的需要加载的 -- > 如果个原来的没有重合的 --> 取消
+        [wself.preloadingModelDic removeAllObjects];
+        NSMutableDictionary *indexDic = wself.preloadingModelDic; // 采用全局的字典 减少快速切换时 重复创建消耗性能的问题
+        indexDic[[NSString stringWithFormat:@"%d",leftCellIndex]] = @1;
+        indexDic[[NSString stringWithFormat:@"%d",model.index]] = @1;
+        indexDic[[NSString stringWithFormat:@"%d",rightCellIndex]] = @1;
+
+        for (NSString *indexStr in wself.loadingImageModelDic.allKeys) {
+            if (indexDic[indexStr]) continue;
+            LBScrollViewStatusModel *loadingModel = wself.loadingImageModelDic[indexStr];
+            if (loadingModel.opreation) {
+                [loadingModel.opreation cancel];
+                loadingModel.opreation = nil;
+            }
+        }
+        [wself.loadingImageModelDic removeAllObjects];
         for (int i = leftCellIndex; i <= rightCellIndex; i++) {
-            model.shouldCancel = NO;
+            LBScrollViewStatusModel *loadingModel = wself.models[i];
+            NSString *indexStr = [NSString stringWithFormat:@"%d",i];
+            wself.loadingImageModelDic[indexStr] = loadingModel;
             if (model.index == i) continue;
             LBScrollViewStatusModel *preloadingModel = wself.models[i];
-            preloadingModel.shouldCancel = NO;
             preloadingModel.currentPageImage = preloadingModel.currentPageImage ?:[wself getCacheImageForModel:preloadingModel];
             if (preloadingModel.currentPageImage) continue;
             [preloadingModel loadImage];
         }
-
-        int finish = 0;
-        for (LBScrollViewStatusModel *obj in wself.models) {
-            if (obj.shouldCancel && obj.opreation) {
-                [obj.opreation cancel];
-                obj.opreation = nil;
-            }
-            if (obj.currentPageImage) {
-                finish = finish + 1;
-            }
-        }
-        if (finish == wself.models.count) {
-            wself.stopPreloading = YES;
-        }
     });
+
 }