iOS 学习 - 23 加载本地 txt 文件, NSMutableParagraphStyle 段落格式,缩放动画,字体间距

思路：

　　1.new 一个 Empty 后缀为 .txt 文件，内容随笔拷贝一段

　　2.用 NSString 接收本地文件，再用一个标题拼接字符串

　　3.创建一个 NSMutableParagraphStyle 实例，设置标题居中、标题距离正文间隔

　　4.创建一个 NSMutableParagraphStyle 实例，设置正文左对齐、每段开头缩进 10

　　5.创建一个基础动画的实例，用代理监听动画结束

话不多说上代码

#pragma mark -- 拼接字符
- (void)loadData:(NSString *)filename {

    //第一个段落
    NSMutableParagraphStyle *first = [[NSMutableParagraphStyle alloc]init];
    first.alignment = NSTextAlignmentCenter;
    first.lineSpacing = ;

    //第二个段落
    NSMutableParagraphStyle *second = [[NSMutableParagraphStyle alloc]init];
    //从左开始写
    second.alignment = NSTextAlignmentLeft;
    //首行缩进
    second.firstLineHeadIndent = ;
    //间距
    second.lineSpacing = ;

    UIFont *titleFont = [UIFont systemFontOfSize:];
    UIFont *contextFont = [UIFont systemFontOfSize:];

    NSMutableAttributedString *str1 = [[NSMutableAttributedString alloc]initWithString:@"游戏许可及服务协议" attributes:@{NSParagraphStyleAttributeName:first,NSFontAttributeName:titleFont}];

    //标题拼接正文，正文前加换行符
    NSString *str = [NSString stringWithFormat:@"\n%@",filename];

    NSMutableAttributedString *str2 = [[NSMutableAttributedString alloc]initWithString:str attributes:@{NSParagraphStyleAttributeName:second,NSFontAttributeName:contextFont}];

    [str1 appendAttributedString:str2];
    _textView.attributedText = str1;
}

#pragma mark -- 关闭动画
- (void)closeAniamtion:(UIView *)view {
    CABasicAnimation *animation = [CABasicAnimation animation];
    animation.keyPath = @"transform.scale";
    animation.toValue = @0.9;
    animation.duration = 0.4;
    animation.delegate = self;
    animation.removedOnCompletion = NO;
    animation.fillMode = kCAFillModeForwards;
    [view.layer addAnimation:animation forKey:@"closeAnimation"];
}

#pragma mark -- 本地 txt 文件内容
- (NSString *)filename {
    //本地 txt 文件
    NSString *path = [[NSBundle mainBundle]pathForResource:@"浅遇时光，静好无恙.txt" ofType:nil];
    //取出内容
    NSString *filename = [[NSString alloc]initWithContentsOfFile:path encoding:NSUTF8StringEncoding error:nil];
    return filename;
}

#pragma mark -- 代理监听动画停止
- (void)animationDidStop:(CAAnimation *)anim finished:(BOOL)flag {

    if ([_bgView.layer animationForKey:@"closeAnimation"] == anim) {
        [_bgView removeFromSuperview];
    }
}

字体间距,中文的文字宽度是相等的,英文和数字的宽度不一样

- (void)baseChinese:(UILabel *)label loadFirst:(NSString *)firstStr second:(NSString *)secondStr
{
    //第一个段落
    NSMutableParagraphStyle *first = [[NSMutableParagraphStyle alloc]init];
    //第二个段落
    NSMutableParagraphStyle *second = [[NSMutableParagraphStyle alloc]init];

    int a = (int)firstStr.length;
    int b = (int)secondStr.length;

    if (a>b) {

        NSDictionary *dict1 = @{NSParagraphStyleAttributeName:first};
        NSMutableAttributedString *firstAttr = [[NSMutableAttributedString alloc]initWithString:firstStr attributes:dict1];
        /** 计算间距 **/
        CGFloat lineGap = label.font.pointSize *(a-b)/(b-);

        NSString *longSecondStr = [NSString stringWithFormat:@"\n%@",secondStr];
        NSMutableAttributedString *secondAttr = [[NSMutableAttributedString alloc]initWithString:longSecondStr attributes:@{NSParagraphStyleAttributeName:second}];
        NSRange range = {,b};
        /** 添加间距属性 **/
        [secondAttr addAttribute:NSKernAttributeName value:[NSNumber numberWithFloat:lineGap] range:range];
        /** 拼接字符串 **/
        [firstAttr appendAttributedString:secondAttr];
        label.attributedText = firstAttr;

    }else if(b>a){

        NSRange range = {,a};
        /** 计算间距 **/
        CGFloat lineGap = label.font.pointSize *(b-a)/(a-);
        NSDictionary *dict1 = @{NSParagraphStyleAttributeName:first};
        NSMutableAttributedString *firstAttr = [[NSMutableAttributedString alloc]initWithString:firstStr attributes:dict1];
        /** 添加间距属性 **/
        [firstAttr addAttribute:NSKernAttributeName value:[NSNumber numberWithFloat:lineGap] range:range];

        NSString *longSecondStr = [NSString stringWithFormat:@"\n%@",secondStr];
        NSMutableAttributedString *secondAttr = [[NSMutableAttributedString alloc]initWithString:longSecondStr attributes:@{NSParagraphStyleAttributeName:second}];
        /** 拼接字符串 **/
        [firstAttr appendAttributedString:secondAttr];
        label.attributedText = firstAttr;

    }else{
        /** 如果相等,直接拼接 **/
        label.text = [NSString stringWithFormat:@"%@\n%@",firstStr,secondStr];
    }
}

完整代码在 github 上，传送门