ios 在UIView上画图，线条

1.画线条（实线，虚线）

- (void)drawRect:(CGRect)rect

{

CGContextRef context = UIGraphicsGetCurrentContext();

[self drawXLine:context rect:rect];

[self drawLegend:context rect:rect];

}

-(CGContextRef)drawXLine:(CGContextRef)context rect:(CGRect)rect
{CGContextSetStrokeColorWithColor(context, [UIColor redColor].CGColor);//float partren[] = {2,3};//CGContextSetLineDash(context, 0,partren , 2); //画虚线
    CGContextMoveToPoint(context, 10, 0);CGContextAddLineToPoint(context, 0, 100);CGContextStrokePath(context);return context;
}

2.画图例说明

//画图例说明
-(void)drawLegend:(CGContextRef)context rect:(CGRect)_rect
{CGSize          myShadowOffset = CGSizeMake (2,  2);//矩形和阴影的位置
    CGContextSaveGState(context);CGContextSetFillColorWithColor(context, [UIColor colorWithRed:0.9 green:0.9 blue:0.9 alpha:1].CGColor);CGContextSetShadow (context, myShadowOffset, 2);   //背景的阴影CGContextFillRect(context, CGRectMake(self.frame.size.width/2-100, [UIScreen mainScreen].bounds.size.height-80, 200, 25.0));NSArray *groupTitle = [NSArray arrayWithObjects:@"提出问题数量",@"方案采纳数量", nil];int legendCount = [groupTitle count];int stepWidth = 15;for (int i = 0; i < legendCount; i++) {if (i == 0){//设定第一个图例的颜色CGContextSetFillColorWithColor(context, [UIColor colorWithRed:64.0/255.0 green:104.0/255.0 blue:168.0/255.0 alpha:1.0].CGColor);}else {//设定第二个图例的颜色CGContextSetFillColorWithColor(context, [UIColor colorWithRed:240.0/255.0 green:152.0/255.0 blue:56.0/255.0 alpha:1.0].CGColor);}CGContextSetShadow (context, myShadowOffset, 1);CGContextFillRect(context, CGRectMake(stepWidth + 50, [UIScreen mainScreen].bounds.size.height-72, 10, 10));  //小方块的大小以及位置
        UILabel *label2 = [[UILabel alloc] initWithFrame:CGRectMake(stepWidth+65, [UIScreen mainScreen].bounds.size.height-76, _rect.size.width, 18)];   //声明UIlbel并指定其位置和长宽label2.backgroundColor = [UIColor clearColor];                   //设置label的背景色，这里设置为透明色。label2.font = [UIFont fontWithName:@"Helvetica-Bold" size:12];   //设置label的字体和字体大小。//label2.transform = CGAffineTransformMakeRotation(0.1);           //设置label的旋转角度label2.text = [groupTitle objectAtIndex:i];                      //设置label所显示的文本label2.textColor = [UIColor blackColor];                         //设置文本的颜色label2.textAlignment =NSTextAlignmentLeft;                       //设置文本在label中显示的位置，这里为居中。
        [self addSubview:label2];stepWidth += 100;}CGContextRestoreGState(context);
}