項(xiàng)目中需要將網(wǎng)頁(yè)生成長(zhǎng)圖并保存到本地或者分享的功能

廢話不多說(shuō),這里上相關(guān)邏輯的代碼:

由于網(wǎng)頁(yè)并不一定只是一屏幕的高度,一般都是超出屏幕高度,這里就需要去判斷增加高度.

// 生成長(zhǎng)圖
- (UIImage *)snapshotViewFromRect:(CGRect)rect withCapInsets:(UIEdgeInsets)capInsets {
    
    CGFloat scale = [UIScreen mainScreen].scale;
    
    CGSize boundsSize = self.web.bounds.size;
    CGFloat boundsWidth = boundsSize.width;
    CGFloat boundsHeight = boundsSize.height;
    
    CGSize contentSize = self.web.scrollView.contentSize;
    CGFloat contentHeight = contentSize.height;
    CGFloat contentWidth = contentSize.width;
    
    CGPoint offset = self.web.scrollView.contentOffset;

    [self.web.scrollView setContentOffset:CGPointMake(0, 0)];
    
    NSMutableArray *images = [NSMutableArray array];
    while (contentHeight > 0) {
        UIGraphicsBeginImageContextWithOptions(boundsSize, NO, [UIScreen mainScreen].scale);
        // 在當(dāng)前上下文中渲染出webView
        // 如果取webView.scrollView.layer則會(huì)超出一屏的數(shù)據(jù)不能顯示,只能顯示白色區(qū)域塊
        [self.web.layer renderInContext:UIGraphicsGetCurrentContext()];
        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        [images addObject:image];
        
        CGFloat offsetY = self.web.scrollView.contentOffset.y;
        // 設(shè)置webView的偏移量
        [self.web.scrollView setContentOffset:CGPointMake(0, offsetY + boundsHeight)];
        contentHeight -= boundsHeight;
    }
    
    
    [self.web.scrollView setContentOffset:offset];
    
    CGSize imageSize = CGSizeMake(contentSize.width * scale,
                                  contentSize.height * scale);
    UIGraphicsBeginImageContext(imageSize);
    [images enumerateObjectsUsingBlock:^(UIImage *image, NSUInteger idx, BOOL *stop) {
        [image drawInRect:CGRectMake(0,
                                     scale * boundsHeight * idx,
                                     scale * boundsWidth,
                                     scale * boundsHeight)];
    }];
    // 截取當(dāng)前上下文生成Image
    UIImage *fullImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    UIImageView *snapshotView = [[UIImageView alloc]initWithFrame:CGRectMake(rect.origin.x, rect.origin.y, rect.size.width, rect.size.height)];
    
    snapshotView.image = [fullImage resizableImageWithCapInsets:capInsets];
    
    return snapshotView.image;
}

生成長(zhǎng)圖之后分享圖片:
這里是采用的友盟分享,分享圖片并不是非得下載存儲(chǔ)圖片,

@property (nonatomic,strong) UIImage *shareImage; // 生成長(zhǎng)圖

// 圖片分享
- (void)shareImageToPlatformType:(UMSocialPlatformType)platformType {
    //創(chuàng)建分享消息對(duì)象
    UMSocialMessageObject *messageObject = [UMSocialMessageObject messageObject];
    
    //創(chuàng)建圖片內(nèi)容對(duì)象
    UMShareImageObject *shareObject = [[UMShareImageObject alloc] init];
    //如果有縮略圖昂儒，則設(shè)置縮略圖
//    shareObject.thumbImage = [UIImage imageNamed:@"AppIcon"];
    // 設(shè)置分享上圖中的圖片
    [shareObject setShareImage:self.shareImage];
    
    //分享消息對(duì)象設(shè)置分享內(nèi)容對(duì)象
    messageObject.shareObject = shareObject;
    
    //調(diào)用分享接口
    [[UMSocialManager defaultManager] shareToPlatform:platformType messageObject:messageObject currentViewController:self completion:^(id data, NSError *error) {
        if (error) {
            ZLLog(@"************Share fail with error %@*********",error);
        }else{
            ZLLog(@"response data is %@",data);
        }
    }];
}

生成長(zhǎng)圖之后也有需求是需要保存在本地:

- (void)screenshotPic {
    
    CGRect snapshotFrame = CGRectMake(0, 0, _web.scrollView.contentSize.width, _web.scrollView.contentSize.height);
    UIEdgeInsets snapshotEdgeInsets = UIEdgeInsetsZero;
    UIImage *shareImage = [self snapshotViewFromRect:snapshotFrame withCapInsets:snapshotEdgeInsets];
    self.shareImage = shareImage;
    
    // 存儲(chǔ)到相冊(cè)
    UIImageWriteToSavedPhotosAlbum(shareImage, self, nil, NULL);
    
//    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.7 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ // 延時(shí)0.7s
        [MBProgressHUD showSuccess:@"已保存至相冊(cè)"];
//    });
    
}

這里一點(diǎn)擊保存相冊(cè)就發(fā)現(xiàn)閃退了句灌。發(fā)現(xiàn) Xcode 報(bào)以下錯(cuò)誤:

This app has crashed because it attempted to access privacy-sensitive data without a usage description.  The app's Info.plist must contain an NSPhotoLibraryAddUsageDescription key with a string value explaining to the user how the app uses this data.

問(wèn)題跟 iOS 10 保存圖片蝉衣、調(diào)用相機(jī)一樣吹截， Info.plist 里面要涉及隱私數(shù)據(jù)時(shí)要添加提示語(yǔ)粉怕。
打開(kāi) Info.plist犁珠，點(diǎn)擊 + 號(hào)缭裆，在 Key 中輸入：Privacy - Photo Library Additions Usage Description颤枪，Type 選擇 String底挫，Value 中輸入你的提示語(yǔ)恒傻。

這是 iOS 11 新出的一條隱私規(guī)則，說(shuō)明如下：
iOS11下建邓，蘋(píng)果對(duì)相冊(cè)的權(quán)限key做了調(diào)整盈厘，原來(lái)NSPhotoLibraryUsageDescription，在iOS11之后官边，改成了NSPhotoLibraryAddUsageDescription

iOS 11 新增的隱私設(shè)置
iOS 11 中新加的還有一個(gè)跟 NFC 設(shè)備有關(guān) NFCReaderUsageDescription沸手，不過(guò)暫時(shí)沒(méi)接觸到。