ios通过按钮点击异步加载图片_IOS

比较原始的方法：

复制代码 代码如下:

AsyncImageView.h:
#import <UIKit/UIKit.h>
@interface AsyncImageView : UIView
{
    NSURLConnection* connection;
    NSMutableData* data;
}
- (void)loadImageFromURL:(NSURL*)url;
@end
AsyncImageView.m:
#import "AsyncImageView.h"
@implementation AsyncImageView
- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if(self) {
        // Initialization code
    }
    returnself;
}
- (void)loadImageFromURL:(NSURL*)url {
    if(connection!=nil) { [connection release]; }
    if(data!=nil) { [data release]; }
    NSURLRequest* request = [NSURLRequest requestWithURL:url
                                             cachePolicy:NSURLRequestUseProtocolCachePolicy
                                         timeoutInterval:60.0];
    connection = [[NSURLConnection alloc]
                  initWithRequest:request delegate:self];
}
- (void)connection:(NSURLConnection *)theConnection
    didReceiveData:(NSData *)incrementalData {
    if(data==nil) {
        data =
        [[NSMutableData alloc] initWithCapacity:2048];
    }
    [data appendData:incrementalData];
}
- (void)connectionDidFinishLoading:(NSURLConnection*)theConnection {
    [connection release];
    connection=nil;
    if([[self subviews] count] > 0) {
        [[[self subviews] objectAtIndex:0] removeFromSuperview];
    }
    UIImageView *imageView = [[[UIImageView alloc] initWithImage:[UIImage imageWithData:data]] autorelease];
    imageView.contentMode = UIViewContentModeScaleAspectFit;
    imageView.autoresizingMask = ( UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight );
    [self addSubview:imageView];
    imageView.frame = self.bounds;
    [imageView setNeedsLayout];
    [self setNeedsLayout];
    [data release];
    data=nil;
}
- (UIImage*) image {
    UIImageView* iv = [[self subviews] objectAtIndex:0];
    return[iv image];
}
- (void)dealloc {
    [connection cancel];
    [connection release];
    [data release];
    [super dealloc];
}
@end

方法二：

复制代码 代码如下:

@interface UIButton (AsyncImage)
//size by point
- (void)setImageFromURL:(NSString *)urlString adjustToSize:(CGSize)size completion:(void (^)(void))completion logo:(UIImage *)logoImage;
@end
@implementation UIButton (AsyncImage)
- (void)setImageFromURL:(NSString *)urlString adjustToSize:(CGSize)size completion:(void (^)(void))completion logo:(UIImage *)logoImage
{
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
        UIImage *image = nil;
        NSURL *url = [NSURL URLWithString:urlString];
        NSData *data = [NSData dataWithContentsOfURL:url];
        image = [UIImage imageWithData:data];   
        if (image) {
            if (!CGSizeEqualToSize(size, CGSizeZero)) {
                image = [UIImage imageWithCGImage:image.CGImage scale:[self scaleImage:image adjustToSize:size] orientation:image.imageOrientation];
            }
            if (logoImage) {
                image = [self addLogoImage:logoImage toImage:image];
            }
            dispatch_async(dispatch_get_main_queue(), ^{
                [self setImage:image forState:UIControlStateNormal];
                completion();
            });
        }
        else {
            NSLog(@"async load error.");
        }
    });
}
// 缩放图片以适应按钮大小
- (CGFloat)scaleImage:(UIImage *)image adjustToSize:(CGSize)size
{
    CGFloat xScale = size.width / image.size.width;
    CGFloat yScale = size.height / image.size.height;
    return 1.0 / MIN(xScale, yScale);
}
- (UIImage *)addLogoImage:(UIImage *)logo toImage:(UIImage *)img
{
    //get image width and height
    CGFloat scale = [UIScreen mainScreen].scale;
    int w = scale * img.size.width;
    int h = scale * img.size.height;
    int logoWidth = logo.scale * logo.size.width;
    int logoHeight = logo.scale * logo.size.height;
    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    //create a graphic context with CGBitmapContextCreate
    CGContextRef context = CGBitmapContextCreate(NULL, w, h, 8, 4 * w, colorSpace, kCGImageAlphaPremultipliedFirst);
    CGContextDrawImage(context, CGRectMake(0, 0, w, h), img.CGImage);
    CGContextDrawImage(context, CGRectMake(w - logoWidth, 0, logoWidth, logoHeight), [logo CGImage]);
    CGImageRef imageMasked = CGBitmapContextCreateImage(context);
    CGContextRelease(context);
    CGColorSpaceRelease(colorSpace);
    return [UIImage imageWithCGImage:imageMasked scale:scale orientation:img.imageOrientation];
}
@end

方法三：

#import <Foundation/Foundation.h>
#import "StringUtils.h"

@interface ImageManager : NSObject
{
  NSMutableDictionary *_imageDict;
  NSMutableArray *_imageArr;
}

@property(nonatomic, strong) NSString *httpUrl;
@property(nonatomic, strong) NSMutableDictionary *imageDict;

@property(nonatomic, assign) dispatch_queue_t networkQueue;

+ (ImageManager *) sharedInstance;

- (void)asyncImage:(NSString *)imageName imageView:(UIImageView *)imageView;
//插队
- (void)asyncImageInsert:(NSString *)imageName imageView:(UIImageView *)imageView insert:(BOOL)insert;
//不要在下载之前的数据
- (void)asyncImageCleanOld:(NSString *)imageName imageView:(UIImageView *)imageView cleanOld:(BOOL)cleanOld;

@end

实现文件：

//
// ImageManager.m
// myb-ios
//
// Created by warrior gao on 13-6-5.
// Copyright (c) 2013年 51myb. All rights reserved.
//

#import "ImageManager.h"

@interface ImageManager()

@end

@implementation ImageManager

//缓存图片的最大数量
static int counter = 0;

@synthesize imageDict = _imageDict;

//Singleton
+ (ImageManager *)sharedInstance
{
  static id instance;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    instance = self.new;
  });
  return instance;
}

- (id)init
{
  if((self = [super init]))
  {
    self.networkQueue = dispatch_queue_create("com.warrior.network.image", nil);
    _imageDict = [[NSMutableDictionary alloc] init];
    _imageArr = [[NSMutableArray alloc] init];
  }
  return self;
}

- (NSString *) fileFullPath:(NSString *)fileName
{
  NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0];

  NSString *fileFullPath = [NSString stringWithFormat:@"%@/%@",cachePath,fileName];

  return fileFullPath;
}

//不要在下载之前的数据
- (void)asyncImageCleanOld:(NSString *)imageName imageView:(UIImageView *)imageView cleanOld:(BOOL)cleanOld
{
  if(cleanOld)
  {
    [_imageArr removeAllObjects];
  }

  [self asyncImage:imageName imageView:imageView];
}

//插队，优先
- (void)asyncImageInsert:(NSString *)imageName imageView:(UIImageView *)imageView insert:(BOOL)insert
{
  if([StringUtils isEmpty:imageName]){
    return;
  }

  NSData *data = [NSData dataWithContentsOfFile:[self fileFullPath:[imageName stringByReplacingOccurrencesOfString:@"/" withString:@"-"]]];
  if(data == nil){
    [_imageDict setValue:imageView forKey:imageName];
    if(insert)
    {
      [_imageArr insertObject:imageName atIndex:0];
    }
    else
    {
      [_imageArr addObject:imageName];
    }

    [self cacheImage];
  } else {
    [imageView setImage:[UIImage imageWithData:data]];
  }
}

//正常，附加到后面
- (void)asyncImage:(NSString *)imageName imageView:(UIImageView *)imageView
{
  [self asyncImageInsert:imageName imageView:imageView insert:NO];
}

//异步缓存图片到本地，最多有两个线程
-(void)cacheImage
{
  for (; counter < 2 && _imageArr.count > 0; counter++)
  {
    NSString *imageName = nil;
    @synchronized(self){
      imageName = [[_imageArr objectAtIndex:0] copy];
      [_imageArr removeObjectAtIndex:0];
    }

    if(imageName == nil) continue;

    dispatch_async(self.networkQueue, ^{

      NSLog(@"Starting: %@", imageName);
      UIImage *avatarImage = nil;
      NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"%@%@",self.httpUrl, imageName]];
      NSData *responseData = [NSData dataWithContentsOfURL:url];
      if(responseData.length > 0)
      {
        [responseData writeToFile:[self fileFullPath:[imageName stringByReplacingOccurrencesOfString:@"/" withString:@"-"]] atomically:NO];
        avatarImage = [UIImage imageWithData:responseData];
        NSLog(@"Finishing: %@", imageName);

        if (avatarImage) {
          dispatch_async(dispatch_get_main_queue(), ^{
            UIImageView *imageView = [_imageDict objectForKey:imageName];
            if(imageView != nil && avatarImage != nil){
              [imageView setImage:avatarImage];
            }

            [_imageDict removeObjectForKey:imageName];
            [imageName release];
          });
        }
      }
      counter--;
      [self cacheImage];
    });

  }
}

@end

以上所述就是本文的全部内容 了，希望大家能够喜欢。

以上是小编为您精心准备的的内容，在的博客、问答、公众号、人物、课程等栏目也有的相关内容，欢迎继续使用右上角搜索按钮进行搜索ios
异步加载图片
点击按钮异步加载更多、ios 异步加载图片、ios 异步加载、ios异步加载数据、ios异步加载图片 流畅，以便于您获取更多的相关知识。

时间： 2024-10-26 08:06:14

ios通过按钮点击异步加载图片_IOS的相关文章

ios通过按钮点击异步加载图片

  本文给大家汇总了几种IOS中实现异步加载图片的方法,十分的简单实用,有需要的小伙伴可以参考下. 比较原始的方法: 代码如下: AsyncImageView.h: #import @interface AsyncImageView : UIView { NSURLConnection* connection; NSMutableData* data; } - (void)loadImageFromURL:(NSURL*)url; @end AsyncImageView.m: #import "

jQuery实现按钮点击遮罩加载及处理完后恢复的效果_jquery

本文实例讲述了jQuery实现按钮点击遮罩加载及处理完后恢复的效果.分享给大家供大家参考,具体如下: 运行效果图如下: 具体代码如下: <%@ Page Language="C#" AutoEventWireup="true" CodeFile="EasyUiLoad.aspx.cs" Inherits="EasyUiLoad" %> <!DOCTYPE html PUBLIC "-//W3C//D

Android之ListView异步加载图片且仅显示可见子项中的图片

折腾了好多天,遇到 N 多让人崩溃无语的问题,不过今天终于有些收获了,这是实验的第一版,有些混乱,下一步进行改造细分,先把代码记录在这儿吧. 网上查了很多资料,发现都千篇一律,抄来抄去,很多细节和完整实例都没看到,只有自己一点点研究了,总体感觉 android 下面要显示个图片真不容易啊. 项目主要实现的功能: 异步加载图片 图片内存缓存.异步磁盘文件缓存 解决使用 viewHolder 后出现的图片错位问题 优化列表滚动性能,仅显示可见子项中的图片 无需固定图片显示高度,对高度进行缓存使列表滚

Android中如何异步加载图片

研究了android从网络上异步加载图像,现总结如下: (1)由于android UI更新支持单一线程原则,所以从网络上取数据并更新到界面上,为了不阻塞主线程首先可能会想到以下方法. 在主线程中new 一个Handler对象,加载图像方法如下所示 private void loadImage(final String url, final int id) { handler.post(new Runnable() { public void run() { Drawable drawable =

ios7-ios开发 UITableView异步加载图片，滑动时会很卡

问题描述 ios开发 UITableView异步加载图片,滑动时会很卡 -(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{ static NSString *cellIdentifier = @"cellIdentifier"; BrandTableViewCell *cell = (BrandTableViewCell *)[tab

Android编程学习之异步加载图片的方法_Android

本文实例讲述了Android编程学习之异步加载图片的方法.分享给大家供大家参考,具体如下: 最近在android开发中碰到比较棘手的问题,就是加载图片内存溢出.我开发的是一个新闻应用,应用中用到大量的图片,一个界面中可能会有上百张图片.开发android应用的朋友可能或多或少碰到加载图片内存溢出问题,一般情况下,加载一张大图就会导致内存溢出,同样,加载多张图片内存溢出的概率也很高. 列一下网络上查到的一般做法: 1.使用BitmapFactory.Options对图片进行压缩 2.优化加载图片的

Android 异步加载图片，使用LruCache和SD卡或手机缓存，效果非常的流畅

异步加载图片的例子,网上也比较多,大部分用了HashMap<String, SoftReference<Drawable>> imageCache ,但是现在已经不再推荐使用这种方式了,因为从 Android 2.3 (API Level 9)开始,垃圾回收器会更倾向于回收持有软引用或弱引用的对象,这让软引用和弱引用变得不再可靠.另外,Android 3.0 (API Level 11)中,图片的数据会存储在本地的内存当中,因而无法用一种可预见的方式将其释放,这就有潜在的风险造成应

ajax异步加载图片实例分析_AJAX相关

本文实例讲述了ajax异步加载图片的方法.分享给大家供大家参考,具体如下: 图片一般比较大,所以他们都是在基本网页加载后才逐渐加载上的,整个加载的过程非常不雅观,或者是从模糊逐渐变清晰,或者是从上往下拓展开(当然你也可以认为这些都是不错的特效).如果是通过定时更换img的src属性来实现图片的动态更换,由此带来的闪烁更让它难以接受,这可不是用alt属性就能让人愉快的. 联系时下比较热门的,号称"无"刷新的AJAX技术,利用XMLHttpRequest对象发起异步请求,待图像加载完毕再动

Android实现ListView异步加载图片的方法_Android

本文实例讲述了Android实现ListView异步加载图片的方法.分享给大家供大家参考.具体如下: ListView异步加载图片是非常实用的方法,凡是是要通过网络获取图片资源一般使用这种方法比较好,用户体验好,不用让用户等待下去,下面就说实现方法,先贴上主方法的代码: package cn.wangmeng.test; import java.io.IOException; import java.io.InputStream; import java.lang.ref.SoftReferen