PieChart divides equally when all value of data items are 0

Zhang Hang
Commit 0a28c9c51246ba9daff1da8cf2eaa7aea250f81b 0a28c9c5 1 parent 3f666b10
Showing 1 changed file with 46 additions and 29 deletions
PNChart/PNPieChart.m
--- a/PNChart/PNPieChart.m
View file @0a28c9c
+++ b/PNChart/PNPieChart.m
View file @0a28c9c
@@ -11,8 +11,7 @@
 @interface PNPieChart()
 @property (nonatomic, readwrite) NSArray	*items;
-@property (nonatomic) CGFloat total;
+@property (nonatomic) NSArray *endPercentages;
-@property (nonatomic) CGFloat currentTotal;
 @property (nonatomic) CGFloat outerCircleRadius;
 @property (nonatomic) CGFloat innerCircleRadius;
@@ -21,11 +20,14 @@
 @property (nonatomic) CAShapeLayer *pieLayer;
 @property (nonatomic) NSMutableArray *descriptionLabels;
+
 - (void)loadDefault;
 - (UILabel *)descriptionLabelForItemAtIndex:(NSUInteger)index;
 - (PNPieChartDataItem *)dataItemForIndex:(NSUInteger)index;
-
+- (CGFloat)startPercentageForItemAtIndex:(NSUInteger)index;
+- (CGFloat)endPercentageForItemAtIndex:(NSUInteger)index;
+- (CGFloat)ratioForItemAtIndex:(NSUInteger)index;
 - (CAShapeLayer *)newCircleLayerWithRadius:(CGFloat)radius
                                borderWidth:(CGFloat)borderWidth
                                  fillColor:(UIColor *)fillColor
@@ -58,15 +60,23 @@
     return self;
 }
-
 - (void)loadDefault{
-	_currentTotal = 0;
+    __block CGFloat currentTotal = 0;
-	_total       = 0;
+    CGFloat total = [[self.items valueForKeyPath:@"@sum.value"] floatValue];
+    NSMutableArray *endPercentages = [NSMutableArray new];
+    [_items enumerateObjectsUsingBlock:^(PNPieChartDataItem *item, NSUInteger idx, BOOL *stop) {
+        if (total == 0){
+            [endPercentages addObject:@(1.0/_items.count*(idx+1))];
+        }else{
+            currentTotal += item.value;
+            [endPercentages addObject:@(currentTotal/total)];
+        }
+    }];
+    self.endPercentages = [endPercentages copy];
     [_contentView removeFromSuperview];
     _contentView = [[UIView alloc] initWithFrame:self.bounds];
     [self addSubview:_contentView];
-    [_descriptionLabels removeAllObjects];
     _descriptionLabels = [NSMutableArray new];
     _pieLayer = [CAShapeLayer layer];
@@ -78,39 +88,30 @@
 - (void)strokeChart{
     [self loadDefault];
-	[self.items enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
-		_total +=((PNPieChartDataItem *)obj).value;
-	}];
-	
     PNPieChartDataItem *currentItem;
-	CGFloat currentValue = 0;
     for (int i = 0; i < _items.count; i++) {
         currentItem = [self dataItemForIndex:i];
-		CGFloat startPercnetage = currentValue/_total;
+        CGFloat startPercnetage = [self startPercentageForItemAtIndex:i];
-		CGFloat endPercentage   = (currentValue + currentItem.value)/_total;
+        CGFloat endPercentage   = [self endPercentageForItemAtIndex:i];
-		CAShapeLayer *currentPieLayer =	[self newCircleLayerWithRadius:_innerCircleRadius + (_outerCircleRadius - _innerCircleRadius)/2
+        CGFloat radius = _innerCircleRadius + (_outerCircleRadius - _innerCircleRadius)/2;
-                                                           borderWidth:_outerCircleRadius - _innerCircleRadius
+        CGFloat borderWidth = _outerCircleRadius - _innerCircleRadius;
+        CAShapeLayer *currentPieLayer =	[self newCircleLayerWithRadius:radius
+                                                           borderWidth:borderWidth
                                                              fillColor:[UIColor clearColor]
                                                            borderColor:currentItem.color
                                                        startPercentage:startPercnetage
                                                          endPercentage:endPercentage];
         [_pieLayer addSublayer:currentPieLayer];
-		
-		currentValue+=currentItem.value;
-		
     }
     [self maskChart];
-	currentValue = 0;
     for (int i = 0; i < _items.count; i++) {
-		currentItem = [self dataItemForIndex:i];
         UILabel *descriptionLabel =  [self descriptionLabelForItemAtIndex:i];
         [_contentView addSubview:descriptionLabel];
-		currentValue+=currentItem.value;
         [_descriptionLabels addObject:descriptionLabel];
     }
 }
@@ -118,19 +119,17 @@
 - (UILabel *)descriptionLabelForItemAtIndex:(NSUInteger)index{
     PNPieChartDataItem *currentDataItem = [self dataItemForIndex:index];
     CGFloat distance = _innerCircleRadius + (_outerCircleRadius - _innerCircleRadius) / 2;
-    CGFloat centerPercentage =(_currentTotal + currentDataItem.value /2 ) / _total;
+    CGFloat centerPercentage = ([self startPercentageForItemAtIndex:index] + [self endPercentageForItemAtIndex:index])/2;
     CGFloat rad = centerPercentage * 2 * M_PI;
-	_currentTotal += currentDataItem.value;
-	
     UILabel *descriptionLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 100, 80)];
     NSString *titleText = currentDataItem.textDescription;
     if(!titleText){
-        titleText = [NSString stringWithFormat:@"%.0f%%",currentDataItem.value/ _total * 100];
+        titleText = [NSString stringWithFormat:@"%.0f%%",[self ratioForItemAtIndex:index] * 100];
         descriptionLabel.text = titleText ;
     }
     else {
-        NSString* str = [NSString stringWithFormat:@"%.0f%%\n",currentDataItem.value/ _total * 100];
+        NSString* str = [NSString stringWithFormat:@"%.0f%%\n",[self ratioForItemAtIndex:index] * 100];
         str = [str stringByAppendingString:titleText];
         descriptionLabel.text = str ;
     }
@@ -158,6 +157,22 @@
     return self.items[index];
 }
+- (CGFloat)startPercentageForItemAtIndex:(NSUInteger)index{
+    if(index == 0){
+        return 0;
+    }
+    
+    return [_endPercentages[index - 1] floatValue];
+}
+
+- (CGFloat)endPercentageForItemAtIndex:(NSUInteger)index{
+    return [_endPercentages[index] floatValue];
+}
+
+- (CGFloat)ratioForItemAtIndex:(NSUInteger)index{
+    return [self endPercentageForItemAtIndex:index] - [self startPercentageForItemAtIndex:index];
+}
+
 #pragma mark private methods
 - (CAShapeLayer *)newCircleLayerWithRadius:(CGFloat)radius
@@ -188,8 +203,10 @@
 }
 - (void)maskChart{
-	CAShapeLayer *maskLayer =	[self newCircleLayerWithRadius:_innerCircleRadius + (_outerCircleRadius - _innerCircleRadius)/2
+    CGFloat radius = _innerCircleRadius + (_outerCircleRadius - _innerCircleRadius)/2;
-                                                 borderWidth:_outerCircleRadius - _innerCircleRadius
+    CGFloat borderWidth = _outerCircleRadius - _innerCircleRadius;
+    CAShapeLayer *maskLayer =	[self newCircleLayerWithRadius:radius
+                                                 borderWidth:borderWidth
                                                    fillColor:[UIColor clearColor]
                                                  borderColor:[UIColor blackColor]
                                              startPercentage:0