「ALAsset Libraryを使ってiPhonePhoto Libraryの全画像にアクセスし、iPhoneSimulatorのようにUIScrollViewで表示する方法」のチュートリアルです。
まずAssetsLibrary.framework、プロジェクトに追加します。
次に、ファイルにヘッダーファイルをviewController.hインポートします。#import <AssetsLibrary/AssetsLibrary.h>
これはあなたのviewController.hファイルです
#import <UIKit/UIKit.h>
#import <AssetsLibrary/AssetsLibrary.h>
#import "AppDelegate.h"
@interface ViewController : UIViewController <UIScrollViewDelegate>
{
ALAssetsLibrary *assetsLibrary;
NSMutableArray *groups;
ALAssetsGroup *assetsGroup;
// I will show all images on `UIScrollView`
UIScrollView *myScrollView;
UIActivityIndicatorView *activityIndicator;
NSMutableArray *assetsArray;
// Will handle thumbnail of images
NSMutableArray *imageThumbnailArray;
// Will handle original images
NSMutableArray *imageOriginalArray;
UIButton *buttonImage;
}
-(void)displayImages;
-(void)loadScrollView;
@end
そして、これはあなたのviewController.mファイルです -
viewWillAppear:
#import "ViewController.h"
#import <QuartzCore/QuartzCore.h>
@implementation ViewController
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
assetsArray = [[NSMutableArray alloc]init];
imageThumbnailArray = [[NSMutableArray alloc]init];
imageOriginalArray = [[NSMutableArray alloc]init];
myScrollView = [[UIScrollView alloc]initWithFrame:CGRectMake(0.0, 0.0, 320.0, 416.0)];
myScrollView.delegate = self;
myScrollView.contentSize = CGSizeMake(320.0, 416.0);
myScrollView.backgroundColor = [UIColor whiteColor];
activityIndicator = [[UIActivityIndicatorView alloc]initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
activityIndicator.center = myScrollView.center;
[myScrollView addSubview:activityIndicator];
[self.view addSubview:myScrollView];
[activityIndicator startAnimating];
}
viewDidAppear:
-(void)viewDidAppear:(BOOL)animated
{
if (!assetsLibrary) {
assetsLibrary = [[ALAssetsLibrary alloc] init];
}
if (!groups) {
groups = [[NSMutableArray alloc] init];
}
else {
[groups removeAllObjects];
}
ALAssetsLibraryGroupsEnumerationResultsBlock listGroupBlock = ^(ALAssetsGroup *group, BOOL *stop) {
//NSLog(@"group %@",group);
if (group) {
[groups addObject:group];
//NSLog(@"groups %@",groups);
} else {
//Call display Images method here.
[self displayImages];
}
};
ALAssetsLibraryAccessFailureBlock failureBlock = ^(NSError *error) {
NSString *errorMessage = nil;
switch ([error code]) {
case ALAssetsLibraryAccessUserDeniedError:
case ALAssetsLibraryAccessGloballyDeniedError:
errorMessage = @"The user has declined access to it.";
break;
default:
errorMessage = @"Reason unknown.";
break;
}
};
[assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos usingBlock:listGroupBlock failureBlock:failureBlock];
}
そして、これがdisplayImages:メソッド本体です
-(void)displayImages
{
// NSLog(@"groups %d",[groups count]);
for (int i = 0 ; i< [groups count]; i++) {
assetsGroup = [groups objectAtIndex:i];
if (!assetsArray) {
assetsArray = [[NSMutableArray alloc] init];
}
else {
[assetsArray removeAllObjects];
}
ALAssetsGroupEnumerationResultsBlock assetsEnumerationBlock = ^(ALAsset *result, NSUInteger index, BOOL *stop) {
if (result) {
[assetsArray addObject:result];
}
};
ALAssetsFilter *onlyPhotosFilter = [ALAssetsFilter allPhotos];
[assetsGroup setAssetsFilter:onlyPhotosFilter];
[assetsGroup enumerateAssetsUsingBlock:assetsEnumerationBlock];
}
//Seprate the thumbnail and original images
for(int i=0;i<[assetsArray count]; i++)
{
ALAsset *asset = [assetsArray objectAtIndex:i];
CGImageRef thumbnailImageRef = [asset thumbnail];
UIImage *thumbnail = [UIImage imageWithCGImage:thumbnailImageRef];
[imageThumbnailArray addObject:thumbnail];
ALAssetRepresentation *representation = [asset defaultRepresentation];
CGImageRef originalImage = [representation fullResolutionImage];
UIImage *original = [UIImage imageWithCGImage:originalImage];
[imageOriginalArray addObject:original];
}
[self loadScrollView];
}
これで が 2arrayつありimageThumbnailArray、もう 1 つは ですimageOriginalArray。スクロールが遅くならないimageThumbnailArray表示に使用します.... 画像の拡大プレビューに使用します。UIScrollViewimageOriginalArray
'loadScrollView:' メソッド, iPhoneSimulator のように画像を表示する方法UIScrollViewです
#pragma mark - LoadImages on UIScrollView
-(void)loadScrollView
{
float horizontal = 8.0;
float vertical = 8.0;
for(int i=0; i<[imageThumbnailArray count]; i++)
{
if((i%4) == 0 && i!=0)
{
horizontal = 8.0;
vertical = vertical + 70.0 + 8.0;
}
buttonImage = [UIButton buttonWithType:UIButtonTypeCustom];
[buttonImage setFrame:CGRectMake(horizontal, vertical, 70.0, 70.0)];
[buttonImage setTag:i];
[ buttonImage setImage:[imageThumbnailArray objectAtIndex:i] forState:UIControlStateNormal];
[buttonImage addTarget:self action:@selector(buttonImagePressed:) forControlEvents:UIControlEventTouchUpInside];
[myScrollView addSubview:buttonImage];
horizontal = horizontal + 70.0 + 8.0;
}
[myScrollView setContentSize:CGSizeMake(320.0, vertical + 78.0)];
[activityIndicator stopAnimating];
[activityIndicator removeFromSuperview];
}
buttonここで、どの画像がクリックされたかを確認できます -
#pragma mark - Button Pressed method
-(void)buttonImagePressed:(id)sender
{
NSLog(@"you have pressed : %d button",[sender tag]);
}
このチュートリアルがあなたと同じものを検索する多くのユーザーに役立つことを願っています..ありがとう!