Question

我的iPhone应用程序显示一个CollectionView，其中大约有100个图像由标题分隔。图像的大小约为200Kb。在调试导航器中，在滚动CollectionView时，内存增加到1.75 GB。它仍然运行顺畅，但必须有一个原因。

@property (strong, nonatomic) NSArray *picturesMoon;
@property (strong, nonatomic) NSArray *picturesEarth;
@property (strong, nonatomic) NSArray *picturesVenus;
@property (strong, nonatomic) NSArray *picturesMars;
@property (strong, nonatomic) NSDictionary *plistDict;
@property (strong, nonatomic) NSString *picName;
@property (strong, nonatomic) MyCustomCell *myCell;

- (void)viewDidLoad
{
   [super viewDidLoad];
// Do any additional setup after loading the view.


    self.view.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"Milkyway.png"]];

    self.plistDict=[[NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Praxis" ofType:@"plist"]] objectForKey:@"Universe"];

    // Pictures Moon
    picturesMoon = [self.plistDict objectForKey:@"Moon"];

    // Pictures Earth
    picturesEarth = [self.plistDict objectForKey:@"Earth"];

   // Pictures Mars
   picturesMars = [self.plistDict objectForKey:@"Mars"];
}


 - (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView cellForItemAtIndexPath:(NSIndexPath *)indexPath
 {



     self.myCell = [collectionView dequeueReusableCellWithReuseIdentifier:@"collectionCell" forIndexPath:indexPath];

     // Sections
     switch (indexPath.section) {
         case 0:
             self.myCell.imageInCell.image = [UIImage imageNamed:[picturesMoon objectAtIndex:indexPath.item]];
             break;
         case 1:
             self.myCell.imageInCell.image = [UIImage imageNamed:[picturesEarth objectAtIndex:indexPath.item]];
        break;
         case 2:
             self.myCell.imageInCell.image = [UIImage imageNamed:[picturesMars objectAtIndex:indexPath.item]];
             break;
         case 3:
             self.myCell.imageInCell.image = [UIImage imageNamed:[picturesVenus objectAtIndex:indexPath.item]];
             break;
       default:
              break;
      }
      return self.myCell
 }

 - (UICollectionReusableView *) collectionView:(UICollectionView *)collectionView viewForSupplementaryElementOfKind:(NSString *)kind atIndexPath:(NSIndexPath *)indexPath
 {

     // Header for Sections
     HeaderCollectionView *myHeaderView = [collectionView dequeueReusableSupplementaryViewOfKind:kind withReuseIdentifier:@"Header"   forIndexPath:indexPath];
     switch (indexPath.section) {
         case 0:
             myHeaderView.labelOutlet.text = @"Moon";
             break;
         case 1:
             myHeaderView.labelOutlet.text = @"Earth";
             break;
 ...
 ...
          default:
             break
      }
 return myHeaderView;
 }

MyCustomCell只是代码的几行

 #import "MyCustomCell.h"

 @implementation MyCustomCell
 - (id)initWithFrame:(CGRect)frame
 {
     self = [super initWithFrame:frame];
     if (self) {
         // Initialization code
     }  
     return self;
 }

和MyCustomCell的标题只是

 #import <UIKit/UIKit.h>

 @interface MyCustomCell : UICollectionViewCell
 @property (strong, nonatomic) IBOutlet UIImageView *imageInCell;
 @end

Answer 1

[UIImage imageNamed:]缓存图像。大内存占用不一定是个问题，因为如果内存太低，将自动清除缓存。也就是说，如果要避免缓存，可以使用其他方法加载图像，例如：

NSString *imageName = [picturesMars objectAtIndex:indexPath.item];
NSString *imagePath = [[NSBundle mainBundle] pathForResource:imageName ofType:@"PNG"]; // PNG, or whatever file tile you are actually using
UIImage *image = [UIImage imageWithContentsOfFile:imagePath];
self.myCell.imageInCell.image = image;

带图像的UICollectionView：内存增加到1.75 GB

1 个答案: