iOS实现微信分享多张图片功能

前言

微信分享到朋友圈，可分享的类型有：文字类型、图片类型、音乐类型、视频类型和网页类型，但是我们在做图片分享的时候发现微信给的api只能分享一张图片，达不到一些app的需求，而产品汪或者boss想要分享多张图片，比如前段时间我做的一个app，是电商类app，想把商品的图片都分享到朋友圈，查看微信的api根本没有提供api，在这里我们只能用ios系统自带的分享了。

uiactivityviewcontroller

uiactivityviewcontroller是在ios 6开始支持的，同样是不能在apple tv的开发中使用。而且uiactivityviewcontroller是直接继承uiviewcontroller的，这意味着我们需要自己来展示和解散视图。

主要代码

oc代码

uiimage *imagetoshare = [uiimage imagenamed:@"99687078.jpg"];
 uiimage *imagetoshare1 = [uiimage imagenamed:@"2222.jpg"];
 nsarray *activityitems = @[imagetoshare,imagetoshare1];
 uiactivityviewcontroller *activityvc = [[uiactivityviewcontroller alloc]initwithactivityitems:activityitems applicationactivities:nil];
 [self presentviewcontroller:activityvc animated:true completion:nil];

swift代码

let imagetoshare1 = uiimage.init(named: "99687078.jpg")
 let imagetoshare2 = uiimage.init(named: "2222.jpg")
 let activityitems = [imagetoshare1,imagetoshare2]
 let activityvc = uiactivityviewcontroller.init(activityitems: activityitems, applicationactivities: nil)
 self.present(activityvc, animated: true, completion: nil)

运行截图

注意

我们在分享多张图片到朋友圈的时候会发现，我们在不做任何处理的时候，直接从手机相册调取多张图片分享的时候，分享失败。具体什么原因我研究了一下，发现分享的数据总共大小有限制；在这里举个例子，比如电梯，电梯限定的重量是固定的，所以不管你乘坐多少人，乘坐的人比较胖，那就乘坐的人比较少，如果乘坐的人比较瘦，那就可以多坐几个；所以uiactivityviewcontroller分享多张图片到朋友圈的时候，我根据图片数量的多少，然后把图片压缩到指定宽高，比如一张图片，我就压缩成和微信压缩图片一样的大小1280，如果9张我就压缩成500；

代码

压缩图片的方法在下面粘出，其中compressibilityfactor为图片宽高的最大值；

#import "wechatjpegimager.h"
 
#define kcompressibilityfactor 1280.00
 
@implementation wechatjpegimager
 
#pragma mark - 压缩一张图片 最大宽高1280 类似于微信算法
- (uiimage *)getjpegimagerimg:(uiimage *)image{
 cgfloat oldimg_wid = image.size.width;
 cgfloat oldimg_hei = image.size.height;
 //cgfloat aspectratio = oldimg_wid/oldimg_hei;//宽高比
 if(oldimg_wid > kcompressibilityfactor || oldimg_hei > kcompressibilityfactor){
 //超过设置的最大宽度 先判断那个边最长
 if(oldimg_wid > oldimg_hei){
  //宽度大于高度
  oldimg_hei = (kcompressibilityfactor * oldimg_hei)/oldimg_wid;
  oldimg_wid = kcompressibilityfactor;
 }else{
  oldimg_wid = (kcompressibilityfactor * oldimg_wid)/oldimg_hei;
  oldimg_hei = kcompressibilityfactor;
 }
 }
 uiimage *newimg = [self imagewithimage:image scaledtosize:cgsizemake(oldimg_wid, oldimg_hei)];
 nsdata *djpeg = nil;
 if (uiimagepngrepresentation(newimg)==nil) {
 djpeg = uiimagejpegrepresentation(newimg, 0.5);
 }else{
 djpeg = uiimagepngrepresentation(newimg);
 }
 return [uiimage imagewithdata:djpeg];
}
#pragma mark - 压缩多张图片 最大宽高1280 类似于微信算法
- (nsarray *)getjpegimagerimgarr:(nsarray *)imagearr{
 nsmutablearray *newimgarr = [nsmutablearray new];
 for (int i = 0; i<imagearr.count; i++) {
 uiimage *newimg = [self getjpegimagerimg:imagearr[i]];
 [newimgarr addobject:newimg];
 }
 return newimgarr;
}
#pragma mark - 压缩一张图片 自定义最大宽高
- (uiimage *)getjpegimagerimg:(uiimage *)image compressibilityfactor:(cgfloat)compressibilityfactor{
 cgfloat oldimg_wid = image.size.width;
 cgfloat oldimg_hei = image.size.height;
 //cgfloat aspectratio = oldimg_wid/oldimg_hei;//宽高比
 if(oldimg_wid > compressibilityfactor || oldimg_hei > compressibilityfactor){
 //超过设置的最大宽度 先判断那个边最长
 if(oldimg_wid > oldimg_hei){
  //宽度大于高度
  oldimg_hei = (compressibilityfactor * oldimg_hei)/oldimg_wid;
  oldimg_wid = compressibilityfactor;
 }else{
  oldimg_wid = (compressibilityfactor * oldimg_wid)/oldimg_hei;
  oldimg_hei = compressibilityfactor;
 }
 }
 uiimage *newimg = [self imagewithimage:image scaledtosize:cgsizemake(oldimg_wid, oldimg_hei)];
 nsdata *djpeg = nil;
 if (uiimagepngrepresentation(newimg)==nil) {
 djpeg = uiimagejpegrepresentation(newimg, 0.5);
 }else{
 djpeg = uiimagepngrepresentation(newimg);
 }
 return [uiimage imagewithdata:djpeg];
}
#pragma mark - 压缩多张图片 自定义最大宽高
- (nsarray *)getjpegimagerimgarr:(nsarray *)imagearr compressibilityfactor:(cgfloat)compressibilityfactor{
 nsmutablearray *newimgarr = [nsmutablearray new];
 for (int i = 0; i<imagearr.count; i++) {
 uiimage *newimg = [self getjpegimagerimg:imagearr[i] compressibilityfactor:compressibilityfactor];
 [newimgarr addobject:newimg];
 }
 return newimgarr;
}
#pragma mark - 根据宽高压缩图片
- (uiimage *)imagewithimage:(uiimage *)image scaledtosize:(cgsize)newsize{
 uigraphicsbeginimagecontext(newsize);
 [image drawinrect:cgrectmake(0,0,newsize.width,newsize.height)];
 uiimage* newimage = uigraphicsgetimagefromcurrentimagecontext();
 uigraphicsendimagecontext();
 return newimage;
}

demo下载地址：ios实现微信分享多张图片

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