qy1010

//@property (nonatomic, assign) NSInteger lastcontentOffset; //添加此属性的作用，根据差值，判断ScrollView是上滑还是下拉
//<UIScrollViewDelegate >
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{    
    CGFloat hight = scrollView.frame.size.height;
    CGFloat contentOffset = scrollView.contentOffset.y;
    CGFloat distanceFromBottom = scrollView.contentSize.height - contentOffset;
    CGFloat offset = contentOffset - self.lastcontentOffset;
    self.lastcontentOffset = contentOffset;

qy1010

UILabel *headerTitle = [[UILabel alloc] init];
headerTitle.text = NSLocalizedString(@"profile_language_limit", @"语言最多只能选择3个");
headerTitle.textColor = [UIColor colorNamed:@"secondaryTextColor"];
headerTitle.font = [UIFont fontWithName:@"Roboto-Regular" size:11];;

UIView *headerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, self.view.bounds.size.width, 40)];
headerView.backgroundColor = [UIColor colorNamed:@"mainBackgroundColor"];
[headerView addSubview:headerTitle];
[headerTitle mas_makeConstraints:^(MASConstraintMaker *make) {
    make.leading.mas_equalTo(16);

qy1010

//一级指定本地pod文件

//:path => 指定本地路径
  pod 'XXSdk',:path => 'XXSdkLib'

//2级本地pod
    pod 'Gonfig',:path => '../Gonfig'

//demo使用第二级pod
		pod 'A',:path => 'A podspec 文件夹'

qy1010

//保存图片到相册

 //image是要保存的图片
- (void) saveImage:(UIImage *)image{
    
    if (image) {
        UIImageWriteToSavedPhotosAlbum(image, self, @selector(savedPhotoImage:didFinishSavingWithError:contextInfo:), nil);
    };

}

qy1010

//将Objective-C代码转换为C\C++代码
xcrun  -sdk  iphoneos  clang  -arch  arm64  -rewrite-objc  OC源文件  -o  输出的CPP文件
如果需要链接其他框架，使用-framework参数。比如-framework UIKit

qy1010

// 项目内黄色文件夹路径
  NSString *faceEmojiDir = [[NSBundle mainBundle] pathForResource:@"maoboli" ofType:@"ofeffect"];

qy1010

unsigned int count;
    //获取属性列表
    objc_property_t *propertyList = class_copyPropertyList([self class], &count);
    for (unsigned int i=0; i<count; i++) {
        const char *propertyName = property_getName(propertyList[i]);
        NSLog(@"property---->%@", [NSString stringWithUTF8String:propertyName]);
    }
    
    //获取方法列表
    Method *methodList = class_copyMethodList([self class], &count);

qy1010

//可以看出class_createInstance和alloc的不同
id theObject = class_createInstance(NSString.class, sizeof(unsigned));
id str1 = [theObject init];
NSLog(@"%@", [str1 class]);
id str2 = [[NSString alloc] initWithString:@"test"];
NSLog(@"%@", [str2 class]);

qy1010

Class cls = objc_allocateClassPair(MyClass.class, "MySubClass", 0);
class_addMethod(cls, @selector(submethod1), (IMP)imp_submethod1, "v@:");
class_replaceMethod(cls, @selector(method1), (IMP)imp_submethod1, "v@:");
class_addIvar(cls, "_ivar1", sizeof(NSString *), log(sizeof(NSString *)), "i");

objc_property_attribute_t type = {"T", "@\"NSString\""};
objc_property_attribute_t ownership = { "C", "" };
objc_property_attribute_t backingivar = { "V", "_ivar1"};
objc_property_attribute_t attrs[] = {type, ownership, backingivar};

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对对象类的操作：

// 返回给定对象的类名
const char * object_getClassName ( id obj );
// 返回对象的类
Class object_getClass ( id obj );
// 设置对象的类
Class object_setClass ( id obj, Class cls );

获取对象的类定义