//
// ZZTableViewController.m
// 多图片下载
//
// Created by Mac on 16/1/19.
// Copyright © 2016年 Mac. All rights reserved.
//
#import "ZZTableViewController.h"
#import "ZZApp.h"
@interface ZZTableViewController ()
// 用来存放模型
@property (nonatomic, strong) NSArray *
apps;
@property (nonatomic, strong) NSMutableDictionary *
iconDic;
// 用于存放下载操作
@property (nonatomic, strong) NSMutableDictionary *
operations;
@property (nonatomic, strong) NSOperationQueue *
queue;
@end
@implementation ZZTableViewController
- (NSOperationQueue *
)queue
{
if (!
_queue) {
_queue =
[[NSOperationQueue alloc] init];
}
return _queue;
}
- (NSMutableDictionary *
)operations
{
if (!
_operations) {
_operations =
[NSMutableDictionary dictionary];
}
return _operations;
}
- (NSMutableDictionary *
)iconDic{
if (!
_iconDic) {
_iconDic =
[NSMutableDictionary dictionary];
}
return _iconDic;
}
- (NSArray *
)apps
{
if (!
_apps) {
NSMutableArray *tmpArray =
[NSMutableArray array];
NSString *path = [[NSBundle mainBundle] pathForResource:
@"apps.plist" ofType:nil];
NSArray *dicArray =
[NSArray arrayWithContentsOfFile:path];
for (NSDictionary *dic
in dicArray) {
ZZApp *app =
[ZZApp appWithdic:dic];
[tmpArray addObject:app];
}
_apps =
tmpArray;
}
return _apps;
}
- (
void)viewDidLoad {
[super viewDidLoad];
}
- (
void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *
)tableView {
//#warning Incomplete implementation, return the number of sections
return 1;
}
- (NSInteger)tableView:(UITableView *
)tableView numberOfRowsInSection:(NSInteger)section {
#warning Incomplete implementation, return the number of rows
return self.apps.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *
)indexPath
{
static NSString *ID =
@"app";
UITableViewCell *cell =
[tableView dequeueReusableCellWithIdentifier:ID];
ZZApp *app =
self.apps[indexPath.row];
cell.textLabel.text =
app.name;
cell.detailTextLabel.text =
app.download;
UIImage *image =
self.iconDic[app.icon];
if (image) {
// 先判断内存中有没有图片
cell.imageView.image =
image;
}else{
NSString *cachePath =
[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
// 获得文件名
NSString *fileName =
[app.icon lastPathComponent];
// 计算出文件全路径
NSString *file =
[cachePath stringByAppendingString:fileName];
// 加载沙盒数据
NSData *data =
[NSData dataWithContentsOfFile:file];
// 判断沙盒里有没有数据
if (data) {
// 沙盒中有数据
cell.imageView.image =
[UIImage imageWithData:data];
// cell.imageView.image =
// 把数据加载到内存里
[self.iconDic setObject:cell.imageView.image forKey:app.icon];
}else{
// 下载图片
// cell.imageView.image = [UIImage imageNamed:@"屏幕快照 2016-01-19 下午9.54.43"];
// 添加下载操作到字典里
NSOperation *operation =
[self.operations objectForKey:app.icon];
if (!
operation) {
operation = [NSBlockOperation blockOperationWithBlock:^
{
NSURL *url =
[NSURL URLWithString:app.icon];
NSData *data =
[NSData dataWithContentsOfURL:url];
if (!data) {
// 如果下载失败，移除字典里的操作
[self.operations removeObjectForKey:app.icon];
return ;
}
// 回到主线程显示图片
[[NSOperationQueue mainQueue] addOperationWithBlock:^
{
// cell.imageView.image = [UIImage imageWithData:data];
[tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
}];
// 放到沙盒里
[data writeToFile:file atomically:YES];
// 将图片存到缓存中
[self.iconDic setObject:[UIImage imageWithData:data] forKey:app.icon];
// 下载完成，移除操作
[self.operations removeObjectForKey:app.icon];
}];
// 添加到队列里面去
[self.queue addOperation:operation];
// 添加到操作字典里去
[self.operations setObject:operation forKey:app.icon];
}
}
}
return cell;
}
@end
效果：
1.第一次打开从网络上加载时：
2.第二次打开时，从沙盒中加载：
转载于:https://www.cnblogs.com/BJTUzhengli/p/5143670.html
相关资源：异步线程池加载网络图片
