柱状图

#import <CoreGraphics/CoreGraphics.h>

#define kMaxLine 240
#define kXStartPoint 40

- (void)drawRect:(CGRect)rect {	
	CGContextRef context = UIGraphicsGetCurrentContext();	
	CGContextSetRGBFillColor(context, 0.5, 0.21, 0.52, 1.0);	
	CGContextFillRect(context, CGRectMake(0, 0, 320, 480));
	CGContextSetStrokeColorWithColor(context, [UIColor whiteColor].CGColor);	
	CGContextMoveToPoint(context, kXStartPoint, 120);	
	CGContextAddLineToPoint(context, kXStartPoint, 360);	
	CGContextAddLineToPoint(context, 280, 360);	
	CGContextSetLineWidth(context, 5);	
	CGContextStrokePath(context);
	
	NSArray *voteNum = [[NSArray alloc] initWithObjects:@"850000", @"526000", @"750800", @"360500", nil];	
	NSArray *voteItemName = [[NSArray alloc] initWithObjects:@"奥迪", @"别克", @"凯迪拉克", @"大众", nil];
	NSMutableArray *voteNumberStrArry = [[NSMutableArray alloc] init];	
	NSInteger voteNumBiggest = 0;	
	NSInteger Max = 0;	
	NSInteger numOfItem = [voteNum count];
	NSInteger vote_num;
	NSString *voteNumStr;
	NSInteger temp = 0;
	NSInteger c = 0;
	
	for (int i = 0; i < [voteNum count]; i++) {		
		NSInteger a = [[voteNum objectAtIndex:i] integerValue];
		if (c != 0) {
			if (c >= a) {
				temp = c;
				a = temp;	
				c = a;	
			} else {
				temp = a;	
			} 	
		}
		c = a; 
		voteNumBiggest = temp;
	}
	
	for (int i = 0; i < [voteNum count]; i++) {
		vote_num = [[voteNum objectAtIndex:i] integerValue];
		float oneVoteNum = 0.0;
		if (voteNumBiggest > 0 && voteNumBiggest <= 10) {
			oneVoteNum = vote_num * 24.0;
			Max = 10;	
		} else if (voteNumBiggest > 10 && voteNumBiggest <= 100) {
			oneVoteNum = vote_num * 2.4;
			Max = 100;
		} else if(voteNumBiggest > 100 && voteNumBiggest <= 500) {
			oneVoteNum = vote_num * 0.48;
			Max = 500;
		} else if(voteNumBiggest > 500 && voteNumBiggest <= 1000) {
			oneVoteNum = vote_num * 0.24;
			Max = 1000;
		} else if(voteNumBiggest > 1000 &&voteNumBiggest <= 5000) {
			oneVoteNum = vote_num * 0.048;
			Max = 5000;
		} else if(voteNumBiggest >5000 && voteNumBiggest <= 10000) {
			oneVoteNum = vote_num * 0.024;
			Max = 10000;
		} else if(voteNumBiggest > 10000 && voteNumBiggest <= 100000) {
			oneVoteNum = vote_num * 0.0024;
			Max = 100000;
		} else if(voteNumBiggest > 100000 && voteNumBiggest <= 1000000) {
			oneVoteNum = vote_num * 0.00024;
			Max = 1000000;
		}      
		voteNumStr = [NSString stringWithFormat:@"%f", oneVoteNum];
		[voteNumberStrArry addObject:voteNumStr];	
	}
	
	for (int i = 0; i < numOfItem; i++) {
		CGContextSetLineWidth(context, 3);
		CGContextSetStrokeColorWithColor(context, [UIColor whiteColor].CGColor);
		float legPointY = 0.0;
		float q1 = numOfItem + 1;
		float q2 = i + 1;
		float q = q2 / q1 ;
		legPointY = 120 + kMaxLine * q;
		float a = [[voteNumberStrArry objectAtIndex:i] floatValue];
		UIImage *myImage = [[UIImage imageNamed:@"1.png"] stretchableImageWithLeftCapWidth:0.5 topCapHeight:10 ];
		CGRect imageRect = CGRectMake(kXStartPoint, legPointY, a, 20);
		[myImage drawInRect:imageRect];
		CGRect rectangle = CGRectMake(kXStartPoint, legPointY, a, 20);
		CGContextAddRect(context, rectangle);
		CGContextStrokePath(context);
		[[UIColor greenColor] set];
		NSString *n = [voteItemName objectAtIndex:i];
		CGSize mSize = [n sizeWithFont:[UIFont systemFontOfSize:12.0] forWidth:100 lineBreakMode:UILineBreakModeTailTruncation];
		[n drawInRect:CGRectMake(50, rectangle.origin.y - 20, mSize.width, mSize.height) withFont:[UIFont systemFontOfSize:12.0]];
		[[voteNum objectAtIndex:i] drawInRect:CGRectMake(rectangle.size.width + 50, rectangle.origin.y, 70, 20) withFont:[UIFont systemFontOfSize:12.0]];
	}
	
	NSString *zeroPointStr = @"0";
	[zeroPointStr drawInRect:CGRectMake(kXStartPoint, 366, 52, 20) withFont:[UIFont systemFontOfSize:12.0]];
	NSString *halfPointStr = [NSString stringWithFormat:@"%d", Max / 2];
	[halfPointStr drawInRect:CGRectMake(140, 366, 52, 20) withFont:[UIFont systemFontOfSize:12.0]];
	NSString *rightPointStr = [NSString stringWithFormat:@"%d", Max];
	[rightPointStr drawInRect:CGRectMake(270, 366, 52, 20) withFont:[UIFont systemFontOfSize:12.0]];
	
	[voteNum release];
	[voteItemName release];
	[voteNumberStrArry release];
}

 

效果图：