JSJP_School/LN_School/MJPhotoBrowser/MJPhotoView.m

//
//  MJZoomingScrollView.m
//
//  Created by mj on 13-3-4.
//  Copyright (c) 2013年 itcast. All rights reserved.
//

#import "MJPhotoView.h"
#import "MJPhoto.h"
#import "MJPhotoLoadingView.h"
#import "UIImageView+WebCache.h"
#import <QuartzCore/QuartzCore.h>

@interface MJPhotoView ()
{
    BOOL _doubleTap;
    UIImageView *_imageView;
    MJPhotoLoadingView *_photoLoadingView;
    
    //解决加载大图片出现闪退的问题
    Boolean _isHide;
}
@end

@implementation MJPhotoView

- (id)initWithFrame:(CGRect)frame
{
    if ((self = [super initWithFrame:frame])) {
        self.clipsToBounds = YES;
        // 图片
        _imageView = [[UIImageView alloc] init];
        _imageView.contentMode = UIViewContentModeScaleAspectFit;
        [self addSubview:_imageView];
        
        // 进度条
        _photoLoadingView = [[MJPhotoLoadingView alloc] init];
        
        // 属性
        self.backgroundColor = [UIColor clearColor];
        self.delegate = self;
        self.showsHorizontalScrollIndicator = NO;
        self.showsVerticalScrollIndicator = NO;
        self.decelerationRate = UIScrollViewDecelerationRateFast;
        self.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
        
        // 监听点击
        UITapGestureRecognizer *singleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleSingleTap:)];
        singleTap.delaysTouchesBegan = YES;
        singleTap.numberOfTapsRequired = 1;
        [self addGestureRecognizer:singleTap];
        
        UITapGestureRecognizer *doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTap:)];
        doubleTap.numberOfTapsRequired = 2;
        [self addGestureRecognizer:doubleTap];
    }
    return self;
}

#pragma mark - photoSetter
- (void)setPhoto:(MJPhoto *)photo {
    _photo = photo;
    
    [self showImage];
}

#pragma mark 显示图片
- (void)showImage
{
    if (_photo.firstShow) { // 首次显示
        _imageView.image = _photo.placeholder; // 占位图片
        _photo.srcImageView.image = nil;
        
        // 不是gif，就马上开始下载
        if (![_photo.url.absoluteString hasSuffix:@"gif"]) {
            __weak MJPhotoView *photoView = self;
            __weak MJPhoto *photo = _photo;
            [_imageView sd_setImageWithURL:_photo.url placeholderImage:_photo.placeholder options:SDWebImageRetryFailed|SDWebImageLowPriority completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
                
                photo.image = image;
                // 调整frame参数
                [photoView adjustFrame];
            }];
            
            
        }
    } else {
        [self photoStartLoad];
    }
    
    // 调整frame参数
    [self adjustFrame];
}

#pragma mark 开始加载图片
- (void)photoStartLoad
{
    if (_photo.image) {
        self.scrollEnabled = YES;
        _imageView.image = _photo.image;
    } else {
        self.scrollEnabled = NO;
        // 直接显示进度条
        [_photoLoadingView showLoading];
        [self addSubview:_photoLoadingView];
        
        __weak MJPhotoView *photoView = self;
        __weak MJPhotoLoadingView *loading = _photoLoadingView;
        //测试这样是没问题的 后期会不会引起什么呢 先打个标记吧--danson
        __block BOOL isHide = _isHide;
        
        
        [_imageView sd_setImageWithURL:_photo.url placeholderImage:_photo.srcImageView.image options:SDWebImageRetryFailed|SDWebImageLowPriority progress:^(NSInteger receivedSize, NSInteger expectedSize, NSURL * _Nullable targetURL) {
            if (receivedSize > kMinProgress) {
                
                if (!isHide) {
                    
                    loading.progress = (float)receivedSize/expectedSize;
                }
            }
        } completed:^(UIImage * _Nullable image, NSError * _Nullable error, SDImageCacheType cacheType, NSURL * _Nullable imageURL) {
            [photoView photoDidFinishLoadWithImage:image];
        }];
        
    }
}

#pragma mark 加载完毕
- (void)photoDidFinishLoadWithImage:(UIImage *)image
{
    if (image) {
        self.scrollEnabled = YES;
        _photo.image = image;
        [_photoLoadingView removeFromSuperview];
        
        if ([self.photoViewDelegate respondsToSelector:@selector(photoViewImageFinishLoad:)]) {
            [self.photoViewDelegate photoViewImageFinishLoad:self];
        }
    } else {
        [self addSubview:_photoLoadingView];
        [_photoLoadingView showFailure];
    }
    
    // 设置缩放比例
    [self adjustFrame];
}
#pragma mark 调整frame
- (void)adjustFrame
{
    if (_imageView.image == nil) return;
    
    // 基本尺寸参数
    CGSize boundsSize = self.bounds.size;
    CGFloat boundsWidth = boundsSize.width;
    CGFloat boundsHeight = boundsSize.height;
    
    CGSize imageSize = _imageView.image.size;
    CGFloat imageWidth = imageSize.width;
    CGFloat imageHeight = imageSize.height;
    
    
    //NSLog(@"%f,%f----%f,%f",boundsSize.width,boundsSize.height,imageSize.width,imageSize.height);
    
    // 设置伸缩比例
    CGFloat minScale = boundsWidth / imageWidth;
    if (minScale > 1) {
        minScale = 1.0;
    }
    CGFloat maxScale = 2.0;
    if ([UIScreen instancesRespondToSelector:@selector(scale)]) {
        
        maxScale = maxScale / [[UIScreen mainScreen] scale];
    }
    self.maximumZoomScale = maxScale;
    self.minimumZoomScale = minScale;
    self.zoomScale = minScale;
    
    CGRect imageFrame = CGRectMake(0, 0, boundsWidth, imageHeight * boundsWidth / imageWidth);
    // 内容尺寸
    self.contentSize = CGSizeMake(0, imageFrame.size.height);
    
    // y值
    if (imageFrame.size.height < boundsHeight - 40) {
        imageFrame.origin.y = floorf((boundsHeight - imageFrame.size.height) / 2.0);
    } else {
        imageFrame.origin.y = 20;
        imageFrame.size.height -= 20;
    }
    
    if (_photo.firstShow) { // 第一次显示的图片
        _photo.firstShow = NO; // 已经显示过了
        _imageView.frame = [_photo.srcImageView convertRect:_photo.srcImageView.bounds toView:nil];
        
        [UIView animateWithDuration:0.3 animations:^{
            _imageView.frame = imageFrame;
        } completion:^(BOOL finished) {
            // 设置底部的小图片
            _photo.srcImageView.image = _photo.placeholder;
            [self photoStartLoad];
        }];
    } else {
        _imageView.frame = imageFrame;
    }
}

#pragma mark - UIScrollViewDelegate
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
    return _imageView;
}

#pragma mark - 手势处理
- (void)handleSingleTap:(UITapGestureRecognizer *)tap {
    _doubleTap = NO;
    [self performSelector:@selector(hide) withObject:nil afterDelay:0.2];
}
- (void)hide
{
    if (_doubleTap) return;
    
    _isHide = YES;
    
    // 移除进度条
    [_photoLoadingView removeFromSuperview];
    self.contentOffset = CGPointZero;
    
    // 清空底部的小图
    _photo.srcImageView.image = nil;
    
    CGFloat duration = 0.15;
    if (_photo.srcImageView.clipsToBounds) {
        [self performSelector:@selector(reset) withObject:nil afterDelay:duration];
    }
    
    [UIView animateWithDuration:duration + 0.1 animations:^{
        _imageView.frame = [_photo.srcImageView convertRect:_photo.srcImageView.bounds toView:nil];
        
        // gif图片仅显示第0张
        if (_imageView.image.images) {
            _imageView.image = _imageView.image.images[0];
        }
        
        // 通知代理
        if ([self.photoViewDelegate respondsToSelector:@selector(photoViewSingleTap:)]) {
            [self.photoViewDelegate photoViewSingleTap:self];
        }
    } completion:^(BOOL finished) {
        // 设置底部的小图片
        _photo.srcImageView.image = _photo.placeholder;
        
        // 通知代理
        if ([self.photoViewDelegate respondsToSelector:@selector(photoViewDidEndZoom:)]) {
            [self.photoViewDelegate photoViewDidEndZoom:self];
        }
    }];
}

- (void)reset
{
    _imageView.image = _photo.capture;
    _imageView.contentMode = UIViewContentModeScaleToFill;
}

- (void)handleDoubleTap:(UITapGestureRecognizer *)tap {
    _doubleTap = YES;
    
    CGPoint touchPoint = [tap locationInView:self];
    if (self.zoomScale == self.maximumZoomScale) {
        [self setZoomScale:self.minimumZoomScale animated:YES];
    } else {
        [self zoomToRect:CGRectMake(touchPoint.x, touchPoint.y, 1, 1) animated:YES];
    }
}

- (void)dealloc
{
    // 取消请求
    [_imageView sd_setImageWithURL:[NSURL URLWithString:@"file:///abc"]];
}
@end