Tusker/GMImagePicker/GMGridViewController.m

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//
// GMGridViewController.m
// GMPhotoPicker
//
// Created by Guillermo Muntaner Perelló on 19/09/14.
// Copyright (c) 2014 Guillermo Muntaner Perelló. All rights reserved.
//
#import "GMGridViewController.h"
#import "GMImagePickerController.h"
#import "GMAlbumsViewController.h"
#import "GMGridViewCell.h"
#include <Photos/Photos.h>
//Helper methods
@implementation NSIndexSet (Convenience)
- (NSArray *)aapl_indexPathsFromIndexesWithSection:(NSUInteger)section {
NSMutableArray *indexPaths = [NSMutableArray arrayWithCapacity:self.count];
[self enumerateIndexesUsingBlock:^(NSUInteger idx, BOOL *stop) {
[indexPaths addObject:[NSIndexPath indexPathForItem:(NSInteger)idx inSection:(NSInteger)section]];
}];
return indexPaths;
}
@end
@implementation UICollectionView (Convenience)
- (NSArray *)aapl_indexPathsForElementsInRect:(CGRect)rect {
NSArray *allLayoutAttributes = [self.collectionViewLayout layoutAttributesForElementsInRect:rect];
if (allLayoutAttributes.count == 0) { return nil; }
NSMutableArray *indexPaths = [NSMutableArray arrayWithCapacity:allLayoutAttributes.count];
for (UICollectionViewLayoutAttributes *layoutAttributes in allLayoutAttributes) {
NSIndexPath *indexPath = layoutAttributes.indexPath;
[indexPaths addObject:indexPath];
}
return indexPaths;
}
@end
@interface GMImagePickerController ()
- (void)finishPickingAssets:(id)sender;
- (void)dismiss:(id)sender;
- (NSString *)toolbarTitle;
- (UIView *)noAssetsView;
@end
@interface GMGridViewController () <PHPhotoLibraryChangeObserver>
@property (nonatomic, weak) GMImagePickerController *picker;
@property (strong,nonatomic) PHCachingImageManager *imageManager;
@property (assign, nonatomic) CGRect previousPreheatRect;
@end
static CGSize AssetGridThumbnailSize;
NSString * const GMGridViewCellIdentifier = @"GMGridViewCellIdentifier";
@implementation GMGridViewController
{
CGFloat screenWidth;
CGFloat screenHeight;
UICollectionViewFlowLayout *portraitLayout;
UICollectionViewFlowLayout *landscapeLayout;
}
-(id)initWithPicker:(GMImagePickerController *)picker
{
//Custom init. The picker contains custom information to create the FlowLayout
self.picker = picker;
//Ipad popover is not affected by rotation!
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
screenWidth = CGRectGetWidth(picker.view.bounds);
screenHeight = CGRectGetHeight(picker.view.bounds);
}
else
{
if(UIInterfaceOrientationIsLandscape([UIApplication sharedApplication].statusBarOrientation))
{
screenHeight = CGRectGetWidth(picker.view.bounds);
screenWidth = CGRectGetHeight(picker.view.bounds);
}
else
{
screenWidth = CGRectGetWidth(picker.view.bounds);
screenHeight = CGRectGetHeight(picker.view.bounds);
}
}
UICollectionViewFlowLayout *layout = [self collectionViewFlowLayoutForOrientation:[UIApplication sharedApplication].statusBarOrientation];
if (self = [super initWithCollectionViewLayout:layout])
{
//Compute the thumbnail pixel size:
CGFloat scale = [UIScreen mainScreen].scale;
//NSLog(@"This is @%fx scale device", scale);
if(scale >= 3)
{
scale = 2;
}
AssetGridThumbnailSize = CGSizeMake(layout.itemSize.width * scale, layout.itemSize.height * scale);
self.collectionView.allowsMultipleSelection = picker.allowsMultipleSelection;
[self.collectionView registerClass:GMGridViewCell.class
forCellWithReuseIdentifier:GMGridViewCellIdentifier];
self.preferredContentSize = kPopoverContentSize;
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self setupViews];
// Navigation bar customization
if (self.picker.customNavigationBarPrompt) {
self.navigationItem.prompt = self.picker.customNavigationBarPrompt;
}
self.imageManager = [[PHCachingImageManager alloc] init];
[self resetCachedAssets];
[[PHPhotoLibrary sharedPhotoLibrary] registerChangeObserver:self];
if ([self respondsToSelector:@selector(setEdgesForExtendedLayout:)])
{
self.edgesForExtendedLayout = UIRectEdgeNone;
}
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
[self setupButtons];
[self setupToolbar];
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[self updateCachedAssets];
}
- (void)dealloc
{
[self resetCachedAssets];
[[PHPhotoLibrary sharedPhotoLibrary] unregisterChangeObserver:self];
}
- (UIStatusBarStyle)preferredStatusBarStyle {
return self.picker.pickerStatusBarStyle;
}
#pragma mark - Rotation
- (void)willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
return;
}
UICollectionViewFlowLayout *layout = [self collectionViewFlowLayoutForOrientation:toInterfaceOrientation];
//Update the AssetGridThumbnailSize:
CGFloat scale = [UIScreen mainScreen].scale;
AssetGridThumbnailSize = CGSizeMake(layout.itemSize.width * scale, layout.itemSize.height * scale);
[self resetCachedAssets];
//This is optional. Reload visible thumbnails:
for (GMGridViewCell *cell in [self.collectionView visibleCells]) {
NSInteger currentTag = cell.tag;
[self.imageManager requestImageForAsset:cell.asset
targetSize:AssetGridThumbnailSize
contentMode:PHImageContentModeAspectFill
options:nil
resultHandler:^(UIImage *result, NSDictionary *info)
{
// Only update the thumbnail if the cell tag hasn't changed. Otherwise, the cell has been re-used.
if (cell.tag == currentTag) {
[cell.imageView setImage:result];
}
}];
}
[self.collectionView setCollectionViewLayout:layout animated:YES];
}
#pragma mark - Setup
- (void)setupViews
{
self.collectionView.backgroundColor = [UIColor clearColor];
self.view.backgroundColor = [self.picker pickerBackgroundColor];
}
- (void)setupButtons
{
if (self.picker.allowsMultipleSelection) {
NSString *doneTitle = self.picker.customDoneButtonTitle ? self.picker.customDoneButtonTitle : NSLocalizedStringFromTableInBundle(@"picker.navigation.done-button", @"GMImagePicker", [NSBundle bundleForClass:GMImagePickerController.class], @"Done");
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:doneTitle
style:UIBarButtonItemStyleDone
target:self.picker
action:@selector(finishPickingAssets:)];
self.navigationItem.rightBarButtonItem.enabled = (self.picker.autoDisableDoneButton ? self.picker.selectedAssets.count > 0 : TRUE);
} else {
NSString *cancelTitle = self.picker.customCancelButtonTitle ? self.picker.customCancelButtonTitle : NSLocalizedStringFromTableInBundle(@"picker.navigation.cancel-button", @"GMImagePicker", [NSBundle bundleForClass:GMImagePickerController.class], @"Cancel");
self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:cancelTitle
style:UIBarButtonItemStyleDone
target:self.picker
action:@selector(dismiss:)];
}
if (self.picker.useCustomFontForNavigationBar) {
if (self.picker.useCustomFontForNavigationBar) {
NSDictionary* barButtonItemAttributes = @{NSFontAttributeName: [UIFont fontWithName:self.picker.pickerFontName size:self.picker.pickerFontHeaderSize]};
[self.navigationItem.rightBarButtonItem setTitleTextAttributes:barButtonItemAttributes forState:UIControlStateNormal];
[self.navigationItem.rightBarButtonItem setTitleTextAttributes:barButtonItemAttributes forState:UIControlStateSelected];
}
}
}
- (void)setupToolbar
{
self.toolbarItems = self.picker.toolbarItems;
}
#pragma mark - Collection View Layout
- (UICollectionViewFlowLayout *)collectionViewFlowLayoutForOrientation:(UIInterfaceOrientation)orientation
{
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
if(!portraitLayout)
{
portraitLayout = [[UICollectionViewFlowLayout alloc] init];
portraitLayout.minimumInteritemSpacing = self.picker.minimumInteritemSpacing;
int cellTotalUsableWidth = (int)(screenWidth - (self.picker.colsInPortrait-1)*self.picker.minimumInteritemSpacing);
portraitLayout.itemSize = CGSizeMake(cellTotalUsableWidth/self.picker.colsInPortrait, cellTotalUsableWidth/self.picker.colsInPortrait);
double cellTotalUsedWidth = (double)portraitLayout.itemSize.width*self.picker.colsInPortrait;
double spaceTotalWidth = (double)screenWidth-cellTotalUsedWidth;
double spaceWidth = spaceTotalWidth/(double)(self.picker.colsInPortrait-1);
portraitLayout.minimumLineSpacing = spaceWidth;
}
return portraitLayout;
}
else
{
if(UIInterfaceOrientationIsLandscape(orientation))
{
if(!landscapeLayout)
{
landscapeLayout = [[UICollectionViewFlowLayout alloc] init];
landscapeLayout.minimumInteritemSpacing = self.picker.minimumInteritemSpacing;
int cellTotalUsableWidth = (int)(screenHeight - (self.picker.colsInLandscape-1)*self.picker.minimumInteritemSpacing);
landscapeLayout.itemSize = CGSizeMake(cellTotalUsableWidth/self.picker.colsInLandscape, cellTotalUsableWidth/self.picker.colsInLandscape);
double cellTotalUsedWidth = (double)landscapeLayout.itemSize.width*self.picker.colsInLandscape;
double spaceTotalWidth = (double)screenHeight-cellTotalUsedWidth;
double spaceWidth = spaceTotalWidth/(double)(self.picker.colsInLandscape-1);
landscapeLayout.minimumLineSpacing = spaceWidth;
}
return landscapeLayout;
}
else
{
if(!portraitLayout)
{
portraitLayout = [[UICollectionViewFlowLayout alloc] init];
portraitLayout.minimumInteritemSpacing = self.picker.minimumInteritemSpacing;
int cellTotalUsableWidth = (int)(screenWidth - (self.picker.colsInPortrait-1) * self.picker.minimumInteritemSpacing);
portraitLayout.itemSize = CGSizeMake(cellTotalUsableWidth/self.picker.colsInPortrait, cellTotalUsableWidth/self.picker.colsInPortrait);
double cellTotalUsedWidth = (double)portraitLayout.itemSize.width*self.picker.colsInPortrait;
double spaceTotalWidth = (double)screenWidth-cellTotalUsedWidth;
double spaceWidth = spaceTotalWidth/(double)(self.picker.colsInPortrait-1);
portraitLayout.minimumLineSpacing = spaceWidth;
}
return portraitLayout;
}
}
}
#pragma mark - Collection View Data Source
- (NSInteger)numberOfSectionsInCollectionView:(UICollectionView *)collectionView
{
return 1;
}
- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
GMGridViewCell *cell = [collectionView dequeueReusableCellWithReuseIdentifier:GMGridViewCellIdentifier
forIndexPath:indexPath];
// Increment the cell's tag
NSInteger currentTag = cell.tag + 1;
cell.tag = currentTag;
PHAsset *asset = self.assetsFetchResults[(NSUInteger)indexPath.item];
/*if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
NSLog(@"Image manager: Requesting FIT image for iPad");
[self.imageManager requestImageForAsset:asset
targetSize:AssetGridThumbnailSize
contentMode:PHImageContentModeAspectFit
options:nil
resultHandler:^(UIImage *result, NSDictionary *info) {
// Only update the thumbnail if the cell tag hasn't changed. Otherwise, the cell has been re-used.
if (cell.tag == currentTag) {
[cell.imageView setImage:result];
}
}];
}
else*/
{
//NSLog(@"Image manager: Requesting FILL image for iPhone");
[self.imageManager requestImageForAsset:asset
targetSize:AssetGridThumbnailSize
contentMode:PHImageContentModeAspectFill
options:nil
resultHandler:^(UIImage *result, NSDictionary *info) {
// Only update the thumbnail if the cell tag hasn't changed. Otherwise, the cell has been re-used.
if (cell.tag == currentTag) {
[cell.imageView setImage:result];
}
}];
}
[cell bind:asset];
cell.shouldShowSelection = self.picker.allowsMultipleSelection;
// Optional protocol to determine if some kind of assets can't be selected (pej long videos, etc...)
if ([self.picker.delegate respondsToSelector:@selector(assetsPickerController:shouldEnableAsset:)]) {
cell.enabled = [self.picker.delegate assetsPickerController:self.picker shouldEnableAsset:asset];
} else {
cell.enabled = YES;
}
// Setting `selected` property blocks further deselection. Have to call selectItemAtIndexPath too. ( ref: http://stackoverflow.com/a/17812116/1648333 )
if ([self.picker.selectedAssets containsObject:asset]) {
cell.selected = YES;
[collectionView selectItemAtIndexPath:indexPath animated:NO scrollPosition:UICollectionViewScrollPositionNone];
} else {
cell.selected = NO;
}
return cell;
}
#pragma mark - Collection View Delegate
- (BOOL)collectionView:(UICollectionView *)collectionView shouldSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
PHAsset *asset = self.assetsFetchResults[(NSUInteger)indexPath.item];
GMGridViewCell *cell = (GMGridViewCell *)[collectionView cellForItemAtIndexPath:indexPath];
if (!cell.isEnabled) {
return NO;
} else if ([self.picker.delegate respondsToSelector:@selector(assetsPickerController:shouldSelectAsset:)]) {
return [self.picker.delegate assetsPickerController:self.picker shouldSelectAsset:asset];
} else {
return YES;
}
}
- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath
{
PHAsset *asset = self.assetsFetchResults[(NSUInteger)indexPath.item];
[self.picker selectAsset:asset];
if ([self.picker.delegate respondsToSelector:@selector(assetsPickerController:didSelectAsset:)]) {
[self.picker.delegate assetsPickerController:self.picker didSelectAsset:asset];
}
}
- (BOOL)collectionView:(UICollectionView *)collectionView shouldDeselectItemAtIndexPath:(NSIndexPath *)indexPath
{
PHAsset *asset = self.assetsFetchResults[(NSUInteger)indexPath.item];
if ([self.picker.delegate respondsToSelector:@selector(assetsPickerController:shouldDeselectAsset:)]) {
return [self.picker.delegate assetsPickerController:self.picker shouldDeselectAsset:asset];
} else {
return YES;
}
}
- (void)collectionView:(UICollectionView *)collectionView didDeselectItemAtIndexPath:(NSIndexPath *)indexPath
{
PHAsset *asset = self.assetsFetchResults[(NSUInteger)indexPath.item];
[self.picker deselectAsset:asset];
if ([self.picker.delegate respondsToSelector:@selector(assetsPickerController:didDeselectAsset:)]) {
[self.picker.delegate assetsPickerController:self.picker didDeselectAsset:asset];
}
}
- (BOOL)collectionView:(UICollectionView *)collectionView shouldHighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
PHAsset *asset = self.assetsFetchResults[(NSUInteger)indexPath.item];
if ([self.picker.delegate respondsToSelector:@selector(assetsPickerController:shouldHighlightAsset:)]) {
return [self.picker.delegate assetsPickerController:self.picker shouldHighlightAsset:asset];
} else {
return YES;
}
}
- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
PHAsset *asset = self.assetsFetchResults[(NSUInteger)indexPath.item];
if ([self.picker.delegate respondsToSelector:@selector(assetsPickerController:didHighlightAsset:)]) {
[self.picker.delegate assetsPickerController:self.picker didHighlightAsset:asset];
}
}
- (void)collectionView:(UICollectionView *)collectionView didUnhighlightItemAtIndexPath:(NSIndexPath *)indexPath
{
PHAsset *asset = self.assetsFetchResults[(NSUInteger)indexPath.item];
if ([self.picker.delegate respondsToSelector:@selector(assetsPickerController:didUnhighlightAsset:)]) {
[self.picker.delegate assetsPickerController:self.picker didUnhighlightAsset:asset];
}
}
#pragma mark - UICollectionViewDataSource
- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section
{
NSInteger count = (NSInteger)self.assetsFetchResults.count;
return count;
}
#pragma mark - PHPhotoLibraryChangeObserver
- (void)photoLibraryDidChange:(PHChange *)changeInstance
{
// Call might come on any background queue. Re-dispatch to the main queue to handle it.
dispatch_async(dispatch_get_main_queue(), ^{
// check if there are changes to the assets (insertions, deletions, updates)
PHFetchResultChangeDetails *collectionChanges = [changeInstance changeDetailsForFetchResult:self.assetsFetchResults];
if (collectionChanges) {
// get the new fetch result
self.assetsFetchResults = [collectionChanges fetchResultAfterChanges];
UICollectionView *collectionView = self.collectionView;
if (![collectionChanges hasIncrementalChanges] || [collectionChanges hasMoves]) {
// we need to reload all if the incremental diffs are not available
[collectionView reloadData];
} else {
// if we have incremental diffs, tell the collection view to animate insertions and deletions
[collectionView performBatchUpdates:^{
NSIndexSet *removedIndexes = [collectionChanges removedIndexes];
if ([removedIndexes count]) {
[collectionView deleteItemsAtIndexPaths:[removedIndexes aapl_indexPathsFromIndexesWithSection:0]];
}
NSIndexSet *insertedIndexes = [collectionChanges insertedIndexes];
if ([insertedIndexes count]) {
[collectionView insertItemsAtIndexPaths:[insertedIndexes aapl_indexPathsFromIndexesWithSection:0]];
if (self.picker.showCameraButton && self.picker.autoSelectCameraImages) {
for (NSIndexPath *path in [insertedIndexes aapl_indexPathsFromIndexesWithSection:0]) {
[self collectionView:collectionView didSelectItemAtIndexPath:path];
}
}
}
NSIndexSet *changedIndexes = [collectionChanges changedIndexes];
if ([changedIndexes count]) {
[collectionView reloadItemsAtIndexPaths:[changedIndexes aapl_indexPathsFromIndexesWithSection:0]];
}
} completion:NULL];
}
[self resetCachedAssets];
}
});
}
#pragma mark - UIScrollViewDelegate
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
[self updateCachedAssets];
}
#pragma mark - Asset Caching
- (void)resetCachedAssets
{
[self.imageManager stopCachingImagesForAllAssets];
self.previousPreheatRect = CGRectZero;
}
- (void)updateCachedAssets
{
BOOL isViewVisible = [self isViewLoaded] && [[self view] window] != nil;
if (!isViewVisible) { return; }
// The preheat window is twice the height of the visible rect
CGRect preheatRect = self.collectionView.bounds;
preheatRect = CGRectInset(preheatRect, 0.0f, -0.5f * CGRectGetHeight(preheatRect));
// If scrolled by a "reasonable" amount...
CGFloat delta = ABS(CGRectGetMidY(preheatRect) - CGRectGetMidY(self.previousPreheatRect));
if (delta > CGRectGetHeight(self.collectionView.bounds) / 3.0f) {
// Compute the assets to start caching and to stop caching.
NSMutableArray *addedIndexPaths = [NSMutableArray array];
NSMutableArray *removedIndexPaths = [NSMutableArray array];
[self computeDifferenceBetweenRect:self.previousPreheatRect andRect:preheatRect removedHandler:^(CGRect removedRect) {
NSArray *indexPaths = [self.collectionView aapl_indexPathsForElementsInRect:removedRect];
[removedIndexPaths addObjectsFromArray:indexPaths];
} addedHandler:^(CGRect addedRect) {
NSArray *indexPaths = [self.collectionView aapl_indexPathsForElementsInRect:addedRect];
[addedIndexPaths addObjectsFromArray:indexPaths];
}];
NSArray *assetsToStartCaching = [self assetsAtIndexPaths:addedIndexPaths];
NSArray *assetsToStopCaching = [self assetsAtIndexPaths:removedIndexPaths];
[self.imageManager startCachingImagesForAssets:assetsToStartCaching
targetSize:AssetGridThumbnailSize
contentMode:PHImageContentModeAspectFill
options:nil];
[self.imageManager stopCachingImagesForAssets:assetsToStopCaching
targetSize:AssetGridThumbnailSize
contentMode:PHImageContentModeAspectFill
options:nil];
self.previousPreheatRect = preheatRect;
}
}
- (void)computeDifferenceBetweenRect:(CGRect)oldRect andRect:(CGRect)newRect removedHandler:(void (^)(CGRect removedRect))removedHandler addedHandler:(void (^)(CGRect addedRect))addedHandler
{
if (CGRectIntersectsRect(newRect, oldRect)) {
CGFloat oldMaxY = CGRectGetMaxY(oldRect);
CGFloat oldMinY = CGRectGetMinY(oldRect);
CGFloat newMaxY = CGRectGetMaxY(newRect);
CGFloat newMinY = CGRectGetMinY(newRect);
if (newMaxY > oldMaxY) {
CGRect rectToAdd = CGRectMake(newRect.origin.x, oldMaxY, newRect.size.width, (newMaxY - oldMaxY));
addedHandler(rectToAdd);
}
if (oldMinY > newMinY) {
CGRect rectToAdd = CGRectMake(newRect.origin.x, newMinY, newRect.size.width, (oldMinY - newMinY));
addedHandler(rectToAdd);
}
if (newMaxY < oldMaxY) {
CGRect rectToRemove = CGRectMake(newRect.origin.x, newMaxY, newRect.size.width, (oldMaxY - newMaxY));
removedHandler(rectToRemove);
}
if (oldMinY < newMinY) {
CGRect rectToRemove = CGRectMake(newRect.origin.x, oldMinY, newRect.size.width, (newMinY - oldMinY));
removedHandler(rectToRemove);
}
} else {
addedHandler(newRect);
removedHandler(oldRect);
}
}
- (NSArray *)assetsAtIndexPaths:(NSArray *)indexPaths
{
if (indexPaths.count == 0) { return nil; }
NSMutableArray *assets = [NSMutableArray arrayWithCapacity:indexPaths.count];
for (NSIndexPath *indexPath in indexPaths) {
PHAsset *asset = self.assetsFetchResults[(NSUInteger)indexPath.item];
[assets addObject:asset];
}
return assets;
}
@end