Store image URLs by state in the UIButton category

SDWebImage/UIButton+WebCache.h

@@ -14,6 +14,18 @@
  */
 @interface UIButton (WebCache)
 
+/**
+ * Get the current image URL.
+ */
+- (NSURL *)currentImageURL;
+
+/**
+ * Get the image URL for a control state.
+ * 
+ * @param state Which state you want to know the URL for. The values are described in UIControlState.
+ */
+- (NSURL *)imageURLForState:(UIControlState)state;
+
 /**
  * Set the imageView `image` with an `url`.
  *

SDWebImage/UIButton+WebCache.m

@@ -9,10 +9,27 @@
 #import "UIButton+WebCache.h"
 #import "objc/runtime.h"
 
+static char imageURLStorageKey;
 static char operationKey;
 
 @implementation UIButton (WebCache)
 
+- (NSURL *)currentImageURL;
+{
+    NSURL *url = self.imageURLStorage[@(self.state)];
+
+    if (!url) {
+        url = self.imageURLStorage[@(UIControlStateNormal)];
+    }
+
+    return url;
+}
+
+- (NSURL *)imageURLForState:(UIControlState)state;
+{
+    return self.imageURLStorage[@(state)];
+}
+
 - (void)setImageWithURL:(NSURL *)url forState:(UIControlState)state
 {
     [self setImageWithURL:url forState:state placeholderImage:nil options:0 completed:nil];
@@ -37,6 +54,8 @@ static char operationKey;
 - (void)setImageWithURL:(NSURL *)url forState:(UIControlState)state placeholderImage:(UIImage *)placeholder options:(SDWebImageOptions)options completed:(SDWebImageCompletedBlock)completedBlock {
     [self cancelCurrentImageLoad];
 
+    self.imageURLStorage[@(state)] = url;
+
     [self setImage:placeholder forState:state];
 
     if (url) {
@@ -112,4 +131,15 @@ static char operationKey;
     }
 }
 
+- (NSMutableDictionary *)imageURLStorage;
+{
+    NSMutableDictionary *storage = objc_getAssociatedObject(self, &imageURLStorageKey);
+    if (!storage) {
+        storage = [NSMutableDictionary dictionary];
+        objc_setAssociatedObject(self, &imageURLStorageKey, storage, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+    }
+
+    return storage;
+}
+
 @end