Merge pull request #303 from wordpress-mobile/issue/9504-no_results_vc_support

Adding support to use a View Controller for the empty view.

Author: ScoutHarris

Pod/Classes/WPMediaPickerViewController.h

@@ -198,6 +198,19 @@
  */
 - (nullable UIView *)emptyViewForMediaPickerController:(nonnull WPMediaPickerViewController *)picker;
 
+/**
+ *  Asks the delegate for an empty view to show when there are no assets
+ *  to be displayed. If no empty view is required, you have to implement this
+ *  method and return `nil`.
+ *
+ *  @param picker The controller object managing the assets picker interface.
+ *  @return An empty view controller to display or `nil` to not display any.
+ *
+ *  If this method is not implemented, a default ViewController with a default
+ *  UILabel will be displayed.
+ */
+- (nullable UIViewController *)emptyViewControllerForMediaPickerController:(nonnull WPMediaPickerViewController *)picker;
+
 @end
 
 
@@ -234,7 +247,8 @@
 @property (nonatomic, strong, readonly, nullable) UISearchBar *searchBar;
 
 /**
- The default empty view. When `emptyViewForMediaPickerController:` is not implemented, use this property to style the mensaje.
+ The default empty view. When `emptyViewForMediaPickerController:` is not implemented,
+ use this property to style the message.
  */
 @property (nonatomic, strong, readonly, nonnull) UILabel *defaultEmptyView;
 
@@ -293,6 +307,13 @@
  */
 - (nonnull UIViewController *)defaultPreviewViewControllerForAsset:(nonnull id<WPMediaAsset>)asset;
 
+/**
+ Return a View Controller to present `defaultEmptyView`.
+ 
+ @return a view controller to present the empty view.
+ */
+- (UIViewController *)defaultEmptyViewController;
+
 /**
  Calculates the appropriate cell height/width given the desired number of cells per line, desired space
  between cells, and total width of the frame containing the cells.

Pod/Classes/WPMediaPickerViewController.m

@@ -49,6 +49,9 @@ @interface WPMediaPickerViewController ()
 
 @property (nonatomic, strong) UIView *emptyView;
 @property (nonatomic, strong) UILabel *defaultEmptyView;
+@property (nonatomic, strong) UIViewController *emptyViewController;
+@property (nonatomic, strong) UIViewController *defaultEmptyViewController;
+
 
 @property (nonatomic, strong) WPActionBar *accessoryActionBar;
 @property (nonatomic, strong) UIButton *selectedActionButton;
@@ -553,6 +556,8 @@ - (void)showCapture {
     return;
 }
 
+#pragma mark - Empty View support
+
 - (UIView *)emptyView
 {
     if (_emptyView) {
@@ -570,8 +575,12 @@ - (UIView *)emptyView
 
 - (void)addEmptyViewToView
 {
-    if (self.emptyView.superview == nil) {
-        [self.collectionView addSubview:_emptyView];
+    if ([self usingEmptyViewController]) {
+        [self addEmptyViewControllerToView];
+    } else {
+        if (self.emptyView.superview == nil) {
+            [self.collectionView addSubview:_emptyView];
+        }
     }
 }
 
@@ -586,6 +595,61 @@ - (UILabel *)defaultEmptyView
     return _defaultEmptyView;
 }
 
+#pragma mark - Empty View Controller support
+
+- (void)addEmptyViewControllerToView
+{
+    if (self.emptyViewController.view.superview == nil) {
+        [self.collectionView addSubview:self.emptyViewController.view];
+        _emptyViewController.view.frame = self.collectionView.frame;
+        [self addChildViewController:_emptyViewController];
+        [_emptyViewController didMoveToParentViewController:self];
+        [self centerEmptyView];
+    }
+}
+
+- (void)removeEmptyViewControllerFromView
+{
+    [_emptyViewController willMoveToParentViewController:nil];
+    [_emptyViewController.view removeFromSuperview];
+    [_emptyViewController removeFromParentViewController];
+}
+
+- (UIViewController *)emptyViewController
+{
+    if (_emptyViewController) {
+        return _emptyViewController;
+    }
+    
+    if ([self usingEmptyViewController]) {
+        _emptyViewController = [self.mediaPickerDelegate emptyViewControllerForMediaPickerController:self];
+    }
+    else {
+        _emptyViewController = self.defaultEmptyViewController;
+    }
+    
+    return _emptyViewController;
+}
+
+- (UIViewController *)defaultEmptyViewController
+{
+    if (_defaultEmptyViewController) {
+        return _defaultEmptyViewController;
+    }
+
+    _defaultEmptyViewController = [[UIViewController alloc] init];
+    UILabel *emptyViewLabel = self.defaultEmptyView;
+    emptyViewLabel.center = _defaultEmptyViewController.view.center;
+    [[_defaultEmptyViewController view] addSubview:emptyViewLabel];
+
+    return _defaultEmptyViewController;
+}
+
+- (BOOL)usingEmptyViewController
+{
+    return [self.mediaPickerDelegate respondsToSelector:@selector(emptyViewControllerForMediaPickerController:)];
+}
+
 #pragma mark - UICollectionViewDataSource
 
 - (void)updateDataWithRemoved:(NSIndexSet *)removed inserted:(NSIndexSet *)inserted changed:(NSIndexSet *)changed moved:(NSArray<id<WPMediaMove>> *)moves {
@@ -633,7 +697,11 @@ - (void)refreshData
 
 - (void)refreshDataAnimated:(BOOL)animated
 {
-    [self.refreshControl beginRefreshing];
+    // Don't show the refreshControl if emptyViewController is being displayed.
+    if (! _emptyViewController) {
+        [self.refreshControl beginRefreshing];
+    }
+
     self.collectionView.allowsSelection = NO;
     self.collectionView.allowsMultipleSelection = NO;
     self.collectionView.scrollEnabled = NO;
@@ -782,11 +850,25 @@ - (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSe
         [self.mediaPickerDelegate mediaPickerController:self didUpdateSearchWithAssetCount:numberOfAssets];
     }
 
-    [self.emptyView setHidden:(numberOfAssets != 0)];
+    [self toggleEmptyViewFor:numberOfAssets];
 
     return numberOfAssets;
 }
 
+- (void)toggleEmptyViewFor:(NSInteger)numberOfAssets
+{
+    if ([self usingEmptyViewController]) {
+        if (numberOfAssets > 0) {
+            [self removeEmptyViewControllerFromView];
+        } else {
+            [self addEmptyViewControllerToView];
+        }
+    } else {
+        [self.emptyView setHidden:(numberOfAssets != 0)];
+    }
+}
+
+
 - (id<WPMediaAsset>)assetForPosition:(NSIndexPath *)indexPath
 {
     NSInteger itemPosition = indexPath.item;
@@ -1319,9 +1401,10 @@ - (void)keyboardWillShowNotification:(NSNotification *)notification
     self.collectionView.contentInset = contentInset;
     self.collectionView.scrollIndicatorInsets = contentInset;
 
-    [self centerEmptyView];
-
-    [self.collectionView.collectionViewLayout invalidateLayout];
+    [UIView animateWithDuration:0.2 animations:^{
+        [self centerEmptyView];
+        [self.collectionView.collectionViewLayout invalidateLayout];
+    }];
 }
 
 - (void)keyboardWillHideNotification:(NSNotification *)notification
@@ -1337,27 +1420,44 @@ - (void)keyboardWillHideNotification:(NSNotification *)notification
     self.collectionView.contentInset = contentInset;
     self.collectionView.scrollIndicatorInsets = contentInset;
 
-    [self centerEmptyView];
-
-    [self.collectionView.collectionViewLayout invalidateLayout];
+    [UIView animateWithDuration:0.2 animations:^{
+        [self centerEmptyView];
+        [self.collectionView.collectionViewLayout invalidateLayout];
+    }];
 }
 
-
 /**
  Centers the empty view taking into account the collection view height and content insets.
  */
 - (void)centerEmptyView
 {
-    self.emptyView.center = self.collectionView.center;
+    if (self.emptyViewController) {
+        CGRect emptyViewFrame = [self getEmptyViewFrame];
+        emptyViewFrame.origin.y -= self.searchBar.frame.size.height/2;
+        _emptyViewController.view.frame = emptyViewFrame;
+    } else {
+        self.emptyView.center = self.collectionView.center;
+        self.emptyView.frame = [self getEmptyViewFrame];
+    }
+}
+
+- (CGRect)getEmptyViewFrame
+{
+    CGRect emptyViewFrame;
+
+    if (_emptyViewController) {
+        emptyViewFrame = self.collectionView.frame;
+    } else {
+        emptyViewFrame = self.emptyView.frame;
+    }
 
-    CGRect emptyViewFrame = self.emptyView.frame;
     CGFloat superviewHeight = self.collectionView.frame.size.height;
     CGFloat totalInsets = self.collectionView.contentInset.top + self.collectionView.contentInset.bottom;
 
     superviewHeight = superviewHeight - totalInsets > 0 ? superviewHeight - totalInsets : superviewHeight;
     emptyViewFrame.origin.y = (superviewHeight / 2.0) - (emptyViewFrame.size.height / 2.0) + self.collectionView.frame.origin.y;
 
-    self.emptyView.frame = emptyViewFrame;
+    return emptyViewFrame;
 }
 
 #pragma mark - UIViewControllerPreviewingDelegate

Pod/Classes/WPNavigationMediaPickerViewController.m

@@ -200,6 +200,13 @@ - (UIView *)emptyViewForMediaPickerController:(WPMediaPickerViewController *)pic
     return picker.defaultEmptyView;
 }
 
+- (UIViewController *)emptyViewControllerForMediaPickerController:(WPMediaPickerViewController *)picker {
+    if ([self.delegate respondsToSelector:@selector(emptyViewControllerForMediaPickerController:)]) {
+        return [self.delegate emptyViewControllerForMediaPickerController:picker];
+    }
+    return picker.defaultEmptyViewController;
+}
+
 - (void)mediaPickerController:(nonnull WPMediaPickerViewController *)picker didFinishPickingAssets:(nonnull NSArray<WPMediaAsset> *)assets {
     if ([self.delegate respondsToSelector:@selector(mediaPickerController:didFinishPickingAssets:)]) {
         [self.delegate mediaPickerController:picker didFinishPickingAssets:assets];

WPMediaPicker.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |s|
   s.name             = "WPMediaPicker"
-  s.version          = "1.1"
+  s.version          = "1.2"
   s.summary          = "WPMediaPicker is an iOS controller that allows capture and picking of media assets."
   s.description      = <<-DESC
                        WPMediaPicker is an iOS controller that allows capture and picking of media assets.