ios笔记 可视化编程字体大小适配

创建个UIButton类目, 名字叫AutoFontSize;

.h文件代码

#import <UIKit/UIKit.h>

#import <objc/runtime.h>

@interface UIButton (AutoFontSize)

@end

@interface UILabel (AutoFontSize)

@end

@interface UITextField (AutoFontSize)

@end

@interface UITextView (AutoFontSize)

@end

.m文件代码

#import "UIButton+AutoFontSize.h"

@implementation UIButton (AutoFontSize)

+ (void)load{

    Method imp =class_getInstanceMethod([selfclass], @selector(initWithCoder:));

    Method myImp =class_getInstanceMethod([selfclass], @selector(myInitWithCoder:));

    method_exchangeImplementations(imp, myImp);

}

- (id)myInitWithCoder:(NSCoder*)aDecode{

    [selfmyInitWithCoder:aDecode];

    if (self) {

        //部分不像改变字体的把tag值设置成333跳过

        if(self.titleLabel.tag != 333){

            CGFloat fontSize =self.titleLabel.font.pointSize;

            self.titleLabel.font = [UIFontsystemFontOfSize:fontSize *OffWidth];

        }

    }

    returnself;

}

@end

@implementation UILabel (AutoFontSize)

+ (void)load{

    Method imp =class_getInstanceMethod([selfclass], @selector(initWithCoder:));

    Method myImp =class_getInstanceMethod([selfclass], @selector(myInitWithCoder:));

    method_exchangeImplementations(imp, myImp);

}

- (id)myInitWithCoder:(NSCoder*)aDecode{

    [selfmyInitWithCoder:aDecode];

    if (self) {

        NSLog(@"%@",self.font);

        //部分不像改变字体的把tag值设置成333跳过

        if(self.tag != 333){

            CGFloat fontSize =self.font.pointSize;

            self.font = [UIFontsystemFontOfSize:fontSize *OffWidth - 1];

        }

    }

    returnself;

}

@end

@implementation UITextField (AutoFontSize)

+ (void)load{

    Method imp =class_getInstanceMethod([selfclass], @selector(initWithCoder:));

    Method myImp =class_getInstanceMethod([selfclass], @selector(myInitWithCoder:));

    method_exchangeImplementations(imp, myImp);

}

- (id)myInitWithCoder:(NSCoder*)aDecode{

    [selfmyInitWithCoder:aDecode];

    if (self) {

        //部分不像改变字体的把tag值设置成333跳过

        if(self.tag != 333){

            CGFloat fontSize =self.font.pointSize;

            self.font = [UIFontsystemFontOfSize:fontSize *OffWidth];

        }

    }

    returnself;

}

@end

@implementation UITextView (AutoFontSize)

+ (void)load{

    Method imp =class_getInstanceMethod([selfclass], @selector(initWithCoder:));

    Method myImp =class_getInstanceMethod([selfclass], @selector(myInitWithCoder:));

    method_exchangeImplementations(imp, myImp);

}

- (id)myInitWithCoder:(NSCoder*)aDecode{

    [selfmyInitWithCoder:aDecode];

    if (self) {

        //部分不像改变字体的把tag值设置成333跳过

        if(self.tag != 333){

            CGFloat fontSize =self.font.pointSize;

            self.font = [UIFontsystemFontOfSize:fontSize *OffWidth];

        }

    }

    returnself;

}

@end

在pch文件里import

#import "UIButton+AutoFontSize.h"

完事

原理:

 中二点的叫rutime黑魔法 :method_exchangeImplementations 交换系统方法, 当系统需要调用initWithCoder方法时使其不去调用initWithCoder而是去调用自己定义的- myInitWithCoder方法, 在方法里把字体大小乘上屏幕比例