The IOS learning nsoperation network downloads pictures involving plist files, reusing cells, taking up bitmaps, caching pools, cleaning up memory __ios

#import "HomeTableViewController.h"

#import "CZApp.h"

@interface Hometableviewcontroller ()

Container for plist file data

@property (Nonatomic,strong) Nsarray *listarray;

Manage queues for global download operations

@property (Nonatomic,strong) Nsoperationqueue *opqueue;

Cache pool for all download operations

@property (Nonatomic,strong) nsmutabledictionary *operationcache;

Caching of all images

@property (Nonatomic,strong) nsmutabledictionary *imagecache;

@end

@implementation Hometableviewcontroller

Lazy load

-(Nsarray *) listarray{

if (_listarray ==nil) {

NSString *path = [[nsbundlemainbundle]pathforresource:@ ' videos.plist ' oftype:nil];

Nsarray *dictarray = [Nsarrayarraywithcontentsoffile:path];

Dictionary Turn model

Nsmutablearray *muarray = [[Nsmutablearrayalloc]init];

For (nsdictionary *dictin Dictarray) {

Czapp *app = [Czappappwithdict:dict];

[Muarray Addobject:app];

}

_listarray = Muarray;

}

Return_listarray;

}

-(Nsmutabledictionary *) operationcache{

if (_operationcache ==nil) {

_operationcache = [Nsmutabledictionarydictionary];

}

Return_operationcache;

}

-(Nsmutabledictionary *) imagecache{

if (_imagecache ==nil) {

_imagecache = [[Nsmutabledictionaryalloc]init];

}

Return_imagecache;

}

-(Nsoperationqueue *) opqueue{

if (_opqueue ==nil) {

_opqueue = [[Nsoperationqueuealloc]init];

}

Return_opqueue;

}

-(void) Viewdidload {

[Superviewdidload];

}

#pragma mark-table View data source

-(Nsinteger) Numberofsectionsintableview: (UITableView *) TableView {

RETURN1;

}

-(Nsinteger) TableView: (UITableView *) TableView numberofrowsinsection: (nsinteger) Section {

Returnself.listArray.count;

}

-(UITableViewCell *) TableView: (UITableView *) TableView Cellforrowatindexpath: (Nsindexpath *) IndexPath {

Hometableviewcell *cell=[tableviewdequeuereusablecellwithidentifier:@ "Cell"];

if (Cell==nil) {

cell=[[hometableviewcellalloc]initwithstyle:uitableviewcellstyledefaultreuseidentifier:@ "Cell"];

Cell.selectionstyle=uitableviewcellselectionstylenone;

}

Czapp *app =self.listarray[indexpath.row];

Cell.label.text = App.video_title;

Cell.detailLabel.text = App.video_subtitle;

Determine if there are pictures in the picture cache pool

if ([self.imageCacheobjectForKey:app.video_img]) {

NSLog (@ "Do not download pictures on the Internet, from the image buffer pool);"

Cell.imageView.image =self.imagecache[app.video_img];

return cell;

}

Show placeholder Pictures

Cell.dimageView.image = [uiimageimagenamed:@ "User_default"];

Download picture (refactoring cut out)

[Selfdownloadimage:indexpath];

return cell;

}

-(void) Downloadimage: (Nsindexpath *) indexpath{

Czapp *app =self.listarray[indexpath.row];

To determine if there is an action in the Operation cache pool for downloading pictures

if (Self.operationcache[app.video_img]) {

NSLog (@ "Desperate to download from the cache pool ...");

Return

}

Multithreading asynchronous

Nsblockoperation *DOWNLOADOP = [nsblockoperationblockoperationwithblock:^{

NSLog (@ "Picture download ...");

1. Download pictures

NSData *data = [nsdatadatawithcontentsofurl:[nsurlurlwithstring:app.video_img]];

UIImage *image = [Uiimageimagewithdata:data];

2. Put the downloaded picture in the Imagecache cache

if (image) {

[Self.imageCachesetObject:image forKey:app.video_img];

To remove an action from the cache pool

[Self.operationCacheremoveObjectForKey:app.video_img];

}