Mac OS 开发 -- 直接扩展系统类的属性之NSView添加backgroudColor属性

来源：互联网发布：网络大学是什么编辑：程序博客网时间：2024/06/06 18:10

使用class_getInstanceMethod方法交换本来的draw方法到自己定义的draw方法，然后绘制背景色

@implementation NSView(BackgroudColor)

@dynamic backgroundColor;

@dynamic gradientColor;

- (void)setBackgroundColor:(NSColor *)backgroundColor{

objc_setAssociatedObject(self, [@"backgroundColor" UTF8String], backgroundColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

static dispatch_once_t once;

dispatch_once(&once, ^{

Method method1 = class_getInstanceMethod([NSView class], @selector(drawRect:));

Method method2 = class_getInstanceMethod([NSView class], @selector(__My_Draw_Rect__:));

method_exchangeImplementations(method1, method2);

});

[self setNeedsDisplay:YES];

}

- (void)setGradientColor:(NSGradient *)gradientColor{

objc_setAssociatedObject(self, [@"gradientColor" UTF8String], gradientColor, OBJC_ASSOCIATION_RETAIN_NONATOMIC);

[self setNeedsDisplay:YES];

}

- (NSColor *)getBackgroundColor{

NSColor *color = objc_getAssociatedObject(self,[@"backgroundColor" UTF8String]);

return color;

}

- (NSGradient *)getGradientColor{

NSGradient *gradient = objc_getAssociatedObject(self,[@"gradientColor" UTF8String]);

return gradient;

}

- (void)__My_Draw_Rect__:(NSRect)dirtyRect{

[self __My_Draw_Rect__:dirtyRect];

NSColor *backgroudColor = [self getBackgroundColor];

if(backgroudColor){

[backgroudColor set];

NSRectFill(dirtyRect);

}

NSGradient *gradient = [self getGradientColor];

if(gradient){

[gradient drawInRect:[self bounds] angle:-90];

}

@end

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