项目中要封装NextButton，开始要处理enable 的不同状态，无法重写enabled的setter方法（可能苹果内部改了其实例变量名字）,后来用重写
setNeedsLayout方法，解决了
-(void)setNeedsLayout
{
if(self.enabled) {
NSLog(@"enabled");
UIColor*color = [UIColorcolorWithPatternImage:[UIImageimageNamed:@"button"]];
UIColor*cl = [colorcolorWithAlphaComponent:1.0f];
[selfsetBackgroundColor:cl];
if(self.highlighted) {
NSLog(@"highlighted");
UIColor*color = [UIColorcolorWithPatternImage:[UIImageimageNamed:@"button"]];
UIColor*cl = [colorcolorWithAlphaComponent:0.9f];
[selfsetBackgroundColor:cl];
}else{
NSLog(@"normal");
UIColor*color = [UIColorcolorWithPatternImage:[UIImageimageNamed:@"button"]];
UIColor*cl = [colorcolorWithAlphaComponent:1.0f];
[selfsetBackgroundColor:cl];
}
}else{
NSLog(@"no enabled");
UIColor*color = [UIColorcolorWithRGBString:@"#D8D9DD"];
[selfsetBackgroundColor:color];
}
}
但后来又有需求要修改其title，用setTitle的方法总不奏效,
后来研究发现，重写了setNeedsLayout方法后，无法再设置title，
就用KVO解决了
-(void)observeValueForKeyPath:(NSString*)keyPath ofObject:(id)object change:(NSDictionary*)change context:(void*)context{
//int age = [[change objectForKey:@"new"] intValue];
//self.ageLabel.text = [NSString stringWithFormat:@"%d",age];
BOOLmyEnable = [[changeobjectForKey:@"enabled"]boolValue];
NSLog(@"myEnable = %d",myEnable);
if(self.enabled) {
UIColor*color = [UIColorcolorWithPatternImage:[UIImageimageNamed:@"button"]];
UIColor*cl = [colorcolorWithAlphaComponent:1.0f];
[selfsetBackgroundColor:cl];
[selfsetTitle:@"enable"forState:UIControlStateNormal];
}else{
UIColor*color = [UIColorcolorWithRGBString:@"#D8D9DD"];
[selfsetBackgroundColor:color];
[selfsetTitle:@"unEnable"forState:UIControlStateNormal];
}
}