区分 8.0 和8.0以前

@@ -8,6 +8,11 @@
 
 #import "YHWebViewProgressView.h"
 
+#define SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(v)  ([[[UIDevice currentDevice] systemVersion] compare:v options:NSNumericSearch] != NSOrderedAscending)
+//大于等于8.0的ios版本
+#define iOS8_OR_LATER SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(@"8.0")
+
+
 #define kAnimationDurationMultiplier (1.8)
 
 @interface YHWebViewProgressView ()
@@ -91,13 +96,17 @@
 - (void)setProgress:(float)progress animated:(BOOL)animated
 {
     BOOL isGrowing = progress > 0.f;
-    UIImageView * maskImageView =[[UIImageView alloc]initWithFrame:CGRectMake(0, 0, CGRectGetWidth(self.progressBarView.frame), CGRectGetHeight(self.progressBarView.frame))];
+    UIImageView * maskImageView = [[UIImageView alloc]init];
+    if (iOS8_OR_LATER) {
+        [maskImageView setFrame:CGRectMake(0, 0, CGRectGetWidth(self.progressBarView.frame), CGRectGetHeight(self.progressBarView.frame))];
+        self.progressBarView.maskView = maskImageView;
+    }else{
+    [maskImageView setFrame:CGRectMake(0, 0, CGRectGetWidth(self.progressBarView.frame), CGRectGetHeight(self.progressBarView.frame))];
     CALayer *layer = [CALayer layer];
     [layer setFrame:CGRectMake(0, 0, CGRectGetWidth(self.progressBarView.frame), CGRectGetHeight(self.progressBarView.frame))];
      [layer setContents:(id)[UIImage imageNamed:@"Mask"].CGImage];
-//    self.progressBarView.maskView = maskImageView;
     [self.progressBarView addSubview:maskImageView];
-    
+    }
     CGFloat originX = -CGRectGetWidth(self.bounds)/2;
     CGPoint positionBegin = CGPointMake(originX+_progress * self.bounds.size.width, CGRectGetHeight(self.progressBarView.frame)/2);
     CGPoint positionEnd = CGPointMake(originX+progress * self.bounds.size.width, CGRectGetHeight(self.progressBarView.frame)/2);