Animated bar graph in iOS - ios

Question

I am drawing a bar chart, it works fine except it dosent have animation. Ex: fill colore 0-50%.
I am using simple DrawRect method to draw here is my code:
- (void)drawRect:(CGRect)rect
{
CGFloat height = self.bounds.size.height;
CGContextRef context = UIGraphicsGetCurrentContext();
// CGContextClearRect(context, rect);
CGContextSetFillColorWithColor(context, [self colorWithR:149 G:21 B:29 A:1].CGColor);
CGFloat barWidth = 52;
int count = 0;
NSNumber *num = [NSNumber numberWithFloat:graphValue];
CGFloat x = count * (barWidth + 10);
CGRect barRect = CGRectMake(x, height - ([num floatValue] * height), barWidth, [num floatValue] * height);
CGContextAddRect(context, barRect);
count++;
CGContextFillPath(context);
}
Please help me know the simple way to add animation.

Answer 1

I believe you want to animate the heights of the bars in the bargraph.
I suggest you implement each bar as a separate UIview, a simple rectangle. You can also put all of them in one view with a custom drawRect. Then you need to scale these views or change their frame inside the animation block of either of the following methods:
+ (void)animateWithDuration:(NSTimeInterval)duration animations:(void (^)(void))animations completion:(void (^)(BOOL finished))completion
OR
+ (void)animateWithDuration:(NSTimeInterval)duration animations:(void (^)(void))animations
For a great tutorial see this.
This is an example if you don't have a lot of time.
[UIView animateWithDuration:1//Amount of time the animation takes.
delay:0//Amount of time after which animation starts.
options: UIViewAnimationCurveEaseOut//How the animation will behave.
animations:^{
//here you can either set a CGAffineTransform, or change your view's frame.
//Both will work just fine.
yourBarView.transform = CGAffineTransformMakeScale (
scaleForX,//say 1, you dont want it to change.
scaleForY//say 20, you want to make it 20 times larger in the y
//direction.
//Note* to animate from a zero height to a finite height change the
//view's frame.
//yourBarView.frame = CGRectMake(0,0,20,100);
);
}
completion:^(BOOL finished){//This block is called when the animation completes.
NSLog(#"Done!");
}];