牛骨文教育服务平台(让学习变的简单)

一效果

如果直接设置会有拉伸等等的状况,这里主要介绍图片显示的一些细节

二:代码

代码实现其实很简单,微博当中用了一个photos来存放九宫格这些图片,然后用了一个photo类来做每个photo,并且在上面显示gif等的样式,很多很多小技巧,直接上代码

九宫格根据行列设置等算法,不难

#import "HWStatusPhotosView.h"
#import "HWPhoto.h"
#import "HWStatusPhotoView.h"

#define HWStatusPhotoWH 70
#define HWStatusPhotoMargin 10
#define HWStatusPhotoMaxCol(count) ((count==4)?2:3)

@implementation HWStatusPhotosView // 9

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {

    }
    return self;
}

- (void)setPhotos:(NSArray *)photos
{
    _photos = photos;

    int photosCount = photos.count;

    // 创建足够数量的图片控件
    // 这里的self.subviews.count不要单独赋值给其他变量
    while (self.subviews.count < photosCount) {
        HWStatusPhotoView *photoView = [[HWStatusPhotoView alloc] init];
        [self addSubview:photoView];
    }

    // 遍历所有的图片控件,设置图片
    for (int i = 0; i<self.subviews.count; i++) {
        HWStatusPhotoView *photoView = self.subviews[i];

        if (i < photosCount) { // 显示
            photoView.photo = photos[i];
            photoView.hidden = NO;
        } else { // 隐藏
            photoView.hidden = YES;
        }
    }
}

- (void)layoutSubviews
{
    [super layoutSubviews];

    // 设置图片的尺寸和位置
    int photosCount = self.photos.count;
    int maxCol = HWStatusPhotoMaxCol(photosCount);
    for (int i = 0; i<photosCount; i++) {
        HWStatusPhotoView *photoView = self.subviews[i];

        int col = i % maxCol;
        photoView.x = col * (HWStatusPhotoWH + HWStatusPhotoMargin);

        int row = i / maxCol;
        photoView.y = row * (HWStatusPhotoWH + HWStatusPhotoMargin);
        photoView.width = HWStatusPhotoWH;
        photoView.height = HWStatusPhotoWH;
    }
}

+ (CGSize)sizeWithCount:(int)count
{
    // 最大列数(一行最多有多少列)
    int maxCols = HWStatusPhotoMaxCol(count);

    int cols = (count >= maxCols)? maxCols : count;
    CGFloat photosW = cols * HWStatusPhotoWH + (cols - 1) * HWStatusPhotoMargin;

    // 行数
    int rows = (count + maxCols - 1) / maxCols;
    CGFloat photosH = rows * HWStatusPhotoWH + (rows - 1) * HWStatusPhotoMargin;

    return CGSizeMake(photosW, photosH);
}
@end

photo的代码

#import "HWStatusPhotoView.h"
#import "HWPhoto.h"
#import "UIImageView+WebCache.h"

@interface HWStatusPhotoView()
@property (nonatomic, weak) UIImageView *gifView;
@end

@implementation HWStatusPhotoView

- (UIImageView *)gifView
{
    if (!_gifView) {
        UIImage *image = [UIImage imageNamed:@"timeline_image_gif"];
        UIImageView *gifView = [[UIImageView alloc] initWithImage:image];
        [self addSubview:gifView];
        self.gifView = gifView;
    }
    return _gifView;
}

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        // 内容模式
        self.contentMode = UIViewContentModeScaleAspectFill;
        // 超出边框的内容都剪掉
        self.clipsToBounds = YES;
    }
    return self;
}

- (void)setPhoto:(HWPhoto *)photo
{
    _photo = photo;

    // 设置图片
    [self sd_setImageWithURL:[NSURL URLWithString:photo.thumbnail_pic] placeholderImage:[UIImage imageNamed:@"timeline_image_placeholder"]];

    // 显示隐藏gif控件
    // 判断是够以gif或者GIF结尾
    self.gifView.hidden = ![photo.thumbnail_pic.lowercaseString hasSuffix:@"gif"];
}

- (void)layoutSubviews
{
    [super layoutSubviews];

    self.gifView.x = self.width - self.gifView.width;
    self.gifView.y = self.height - self.gifView.height;
}

@end

三:注意地方

显示隐藏gif控件

    // 判断是够以gif或者GIF结尾
    self.gifView.hidden = ![photo.thumbnail_pic.lowercaseString hasSuffix:@"gif"];

字符串分类根据字符串字体和最大宽度来得到所占据的高度宽度

/**
 *  根据字符串字体和最大宽度来得到所占据的高度宽度
 *
 *  @param font 字体
 *  @param maxW 最大宽度
 *
 *  @return 长宽size
 */
- (CGSize)sizeWithFont:(UIFont *)font maxW:(CGFloat)maxW
{
    NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
    attrs[NSFontAttributeName] = font;
    CGSize maxSize = CGSizeMake(maxW, MAXFLOAT);
    return [self boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs context:nil].size;
}
/**
 *  在宽度为最大值时候根据字体得到宽高
 *
 *  @param font 字体
 *
 *  @return 长宽size
 */
- (CGSize)sizeWithFont:(UIFont *)font
{
    return [self sizeWithFont:font maxW:MAXFLOAT];
}

UIImageView图片设置

/**
         UIViewContentModeScaleToFill : 图片拉伸至填充整个UIImageView(图片可能会变形)

         UIViewContentModeScaleAspectFit : 图片拉伸至完全显示在UIImageView里面为止(图片不会变形)

         UIViewContentModeScaleAspectFill : 
         图片拉伸至 图片的宽度等于UIImageView的宽度 或者 图片的高度等于UIImageView的高度 为止

         UIViewContentModeRedraw : 调用了setNeedsDisplay方法时,就会将图片重新渲染

         UIViewContentModeCenter : 居中显示
         UIViewContentModeTop,
         UIViewContentModeBottom,
         UIViewContentModeLeft,
         UIViewContentModeRight,
         UIViewContentModeTopLeft,
         UIViewContentModeTopRight,
         UIViewContentModeBottomLeft,
         UIViewContentModeBottomRight,

         经验规律:
         1.凡是带有Scale单词的,图片都会拉伸
         2.凡是带有Aspect单词的,图片都会保持原来的宽高比,图片不会变形
         */

        // 内容模式self(imageView对象)
        self.contentMode = UIViewContentModeScaleAspectFill;
        // 超出边框的内容都剪掉
        self.clipsToBounds = YES;