优化性能：1. 初次进入时，提前渲染相册列表的tableView，避免初次进入相册页时的瞬间空白；2. 每次返回到相册页时，计算选中数量的任务放到后台，提升跳转流畅度

TZImagePickerController/TZImagePickerController/TZImagePickerController.m

@@ -281,12 +281,10 @@
         }];
     }
     
-    if (!_pushPhotoPickerVc) {
     TZAlbumPickerController *albumPickerVc = (TZAlbumPickerController *)self.visibleViewController;
     if ([albumPickerVc isKindOfClass:[TZAlbumPickerController class]]) {
         [albumPickerVc configTableView];
     }
-    }
 }
 
 - (void)showAlertWithTitle:(NSString *)title {
@@ -525,10 +523,10 @@
 - (void)viewDidLoad {
     [super viewDidLoad];
     self.view.backgroundColor = [UIColor whiteColor];
-    self.navigationItem.title = [NSBundle tz_localizedStringForKey:@"Photos"];
+    
     TZImagePickerController *imagePickerVc = (TZImagePickerController *)self.navigationController;
     self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:imagePickerVc.cancelBtnTitleStr style:UIBarButtonItemStylePlain target:imagePickerVc action:@selector(cancelButtonClick)];
-    [self configTableView];
+    
     // 1.6.10 采用微信的方式，只在相册列表页定义backBarButtonItem为返回，其余的顺系统的做法
     self.navigationItem.backBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:[NSBundle tz_localizedStringForKey:@"Back"] style:UIBarButtonItemStylePlain target:nil action:nil];
 }
@@ -537,30 +535,26 @@
     [super viewWillAppear:animated];
     TZImagePickerController *imagePickerVc = (TZImagePickerController *)self.navigationController;
     [imagePickerVc hideProgressHUD];
-    if (_albumArr) {
-        for (TZAlbumModel *albumModel in _albumArr) {
-            albumModel.selectedModels = imagePickerVc.selectedModels;
-        }
-        [_tableView reloadData];
-    } else {
-        [self configTableView];
-    }
     if (imagePickerVc.allowTakePicture) {
         self.navigationItem.title = [NSBundle tz_localizedStringForKey:@"Photos"];
     } else if (imagePickerVc.allowPickingVideo) {
         self.navigationItem.title = [NSBundle tz_localizedStringForKey:@"Videos"];
     }
+    
+    [self configTableView];
 }
 
 - (void)configTableView {
+    dispatch_async(dispatch_get_global_queue(0, 0), ^{
         TZImagePickerController *imagePickerVc = (TZImagePickerController *)self.navigationController;
         [[TZImageManager manager] getAllAlbums:imagePickerVc.allowPickingVideo allowPickingImage:imagePickerVc.allowPickingImage completion:^(NSArray<TZAlbumModel *> *models) {
             _albumArr = [NSMutableArray arrayWithArray:models];
             for (TZAlbumModel *albumModel in _albumArr) {
                 albumModel.selectedModels = imagePickerVc.selectedModels;
             }
-        if (!_tableView) {
             
+            dispatch_async(dispatch_get_main_queue(), ^{
+                if (!_tableView) {
                     CGFloat top = 0;
                     CGFloat tableViewHeight = 0;
                     if (self.navigationController.navigationBar.isTranslucent) {
@@ -583,7 +577,9 @@
                 } else {
                     [_tableView reloadData];
                 }
+            });
         }];
+    });
 }
 
 - (void)dealloc {
@@ -610,10 +606,6 @@
     photoPickerVc.columnNumber = self.columnNumber;
     TZAlbumModel *model = _albumArr[indexPath.row];
     photoPickerVc.model = model;
-    __weak typeof(self) weakSelf = self;
-    [photoPickerVc setBackButtonClickHandle:^(TZAlbumModel *model) {
-        [weakSelf configTableView];
-    }];
     [self.navigationController pushViewController:photoPickerVc animated:YES];
     [tableView deselectRowAtIndexPath:indexPath animated:NO];
 }

TZImagePickerController/TZImagePickerController/TZPhotoPickerController.h

@@ -15,8 +15,6 @@
 @property (nonatomic, assign) NSInteger columnNumber;
 @property (nonatomic, strong) TZAlbumModel *model;
 
-@property (nonatomic, copy) void (^backButtonClickHandle)(TZAlbumModel *model);
-
 @end
 
 

TZImagePickerController/TZImagePickerController/TZPhotoPickerController.m

@@ -71,6 +71,15 @@ static CGSize AssetGridThumbnailSize;
     self.navigationItem.title = _model.name;
     self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:tzImagePickerVc.cancelBtnTitleStr style:UIBarButtonItemStylePlain target:tzImagePickerVc action:@selector(cancelButtonClick)];
     _showTakePhotoBtn = (([[TZImageManager manager] isCameraRollAlbum:_model.name]) && tzImagePickerVc.allowTakePicture);
+    // [self resetCachedAssets];
+}
+
+- (void)fetchAssetModels {
+    TZImagePickerController *tzImagePickerVc = (TZImagePickerController *)self.navigationController;
+    if (_isFirstAppear) {
+        [tzImagePickerVc showProgressHUD];
+    }
+    dispatch_sync(dispatch_get_global_queue(0, 0), ^{
         if (!tzImagePickerVc.sortAscendingByModificationDate && _isFirstAppear && iOS8Later) {
             [[TZImageManager manager] getCameraRollAlbum:tzImagePickerVc.allowPickingVideo allowPickingImage:tzImagePickerVc.allowPickingImage completion:^(TZAlbumModel *model) {
                 _model = model;
@@ -88,22 +97,26 @@ static CGSize AssetGridThumbnailSize;
                 [self initSubviews];
             }
         }
-    // [self resetCachedAssets];
+    });
 }
 
 - (void)initSubviews {
+    dispatch_async(dispatch_get_main_queue(), ^{
+        TZImagePickerController *tzImagePickerVc = (TZImagePickerController *)self.navigationController;
+        [tzImagePickerVc hideProgressHUD];
+        
         [self checkSelectedModels];
         [self configCollectionView];
         [self configBottomToolBar];
+        
+        [self scrollCollectionViewToBottom];
+    });
 }
 
 - (void)viewWillDisappear:(BOOL)animated {
     [super viewWillDisappear:animated];
     TZImagePickerController *tzImagePickerVc = (TZImagePickerController *)self.navigationController;
     tzImagePickerVc.isSelectOriginalPhoto = _isSelectOriginalPhoto;
-    if (self.backButtonClickHandle) {
-        self.backButtonClickHandle(_model);
-    }
 }
 
 - (BOOL)prefersStatusBarHidden {
@@ -151,7 +164,6 @@ static CGSize AssetGridThumbnailSize;
 
 - (void)viewWillAppear:(BOOL)animated {
     [super viewWillAppear:animated];
-    [self scrollCollectionViewToBottom];
     // Determine the size of the thumbnails to request from the PHCachingImageManager
     CGFloat scale = 2.0;
     if ([UIScreen mainScreen].bounds.size.width > 600) {
@@ -159,6 +171,10 @@ static CGSize AssetGridThumbnailSize;
     }
     CGSize cellSize = ((UICollectionViewFlowLayout *)_collectionView.collectionViewLayout).itemSize;
     AssetGridThumbnailSize = CGSizeMake(cellSize.width * scale, cellSize.height * scale);
+    
+    if (!_models) {
+        [self fetchAssetModels];
+    }
 }
 
 - (void)viewDidAppear:(BOOL)animated {

TZImagePickerController/ViewController.m

@@ -200,7 +200,7 @@
     if (self.maxCountTF.text.integerValue <= 0) {
         return;
     }
-    TZImagePickerController *imagePickerVc = [[TZImagePickerController alloc] initWithMaxImagesCount:self.maxCountTF.text.integerValue columnNumber:self.columnNumberTF.text.integerValue delegate:self pushPhotoPickerVc:NO];
+    TZImagePickerController *imagePickerVc = [[TZImagePickerController alloc] initWithMaxImagesCount:self.maxCountTF.text.integerValue columnNumber:self.columnNumberTF.text.integerValue delegate:self pushPhotoPickerVc:YES];
     
     
 #pragma mark - 四类个性化设置，这些参数都可以不传，此时会走默认设置