ios - 如何在ios中点击内圈时检测区域

Question

我想在圆圈内点击时找到该区域。其实我已经做了一个计算，但那是不准确的。

检查我编写的代码片段，以便在我的循环 View 中找到选项卡的位置。

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event" this method

     float  dx = touchLocation.x -160;
     float  dy = touchLocation.y - 240;
     double angle = atan2(touchLocation.x,touchLocation.y);
 /* Device is iPad */
            if (count==4) {


                if(angle>-1.639&&angle<=0.775)
                {
                    area=1;
                    NSLog(@"touched here  1 ********************************** ");
                }
                else if(angle>0.775&&angle<=1.579)
                {
                    area=2;
                    NSLog(@"touched here   2********************************** ");
                }
                else if(angle>1.579&&angle<=2.466)
                {
                    area=3;NSLog(@"touched here   3********************************** ");
                }
                else
                {
                    area=4;NSLog(@"touched here  4 ********************************** ");
                }


            }
            else  if (count==5) {


                if(angle>-1.520&&angle<=0.553)
                {
                    area=1;
                    NSLog(@"touched here  1 ********************************** ");
                }
                else if(angle>0.553&&angle<=1.262)
                {
                    area=2;
                    NSLog(@"touched here   2********************************** ");
                }
                else if(angle>1.262&&angle<=1.884)
                {
                    area=3;NSLog(@"touched here   3********************************** ");
                }
                else if(angle>1.884&&angle<=2.644)
                {
                    area=4;NSLog(@"touched here  4 ********************************** ");
                }

                else
                {
                    area=5;NSLog(@"touched here  5 ********************************** ");
                }


            }
            else  if (count==6) {


                if(angle>-1.5707&&angle<=0.4692)
                {
                    area=1;
                    NSLog(@"touched here  1 ********************************** ");
                }
                else if(angle>0.4692&&angle<=1.0219)
                {
                    area=2;
                    NSLog(@"touched here   2********************************** ");
                }
                else if(angle>1.0219&&angle<=1.5707)
                {
                    area=3;NSLog(@"touched here   3********************************** ");
                }
                else if(angle>1.5707&&angle<=2.1147)
                {
                    area=4;NSLog(@"touched here  4 ********************************** ");
                }
                else if(angle>2.1147&&angle<=2.7245)
                {
                    area=5;NSLog(@"touched here  5 ********************************** ");
                }
                else
                {
                    area=6;NSLog(@"touched here  6 ********************************** ");
                }


            }
            else  if (count==7) {


                if(angle>-1.5707&&angle<=0.3992)
                {
                    area=1;
                    NSLog(@"touched here  1 ********************************** ");
                }
                else if(angle>0.3992&&angle<=0.8602)
                {
                    area=2;
                    NSLog(@"touched here   2********************************** ");
                }
                else if(angle>0.8602&&angle<=1.346)
                {
                    area=3;NSLog(@"touched here   3********************************** ");
                }
                else if(angle>1.346&&angle<=1.812)
                {
                    area=4;NSLog(@"touched here  4 ********************************** ");
                }
                else if(angle>1.812&&angle<=2.304)
                {
                    area=5;NSLog(@"touched here  5 ********************************** ");
                }
                else if(angle>2.304&&angle<=2.828)
                {
                    area=6;NSLog(@"touched here  6 ********************************** ");
                }

                else
                {
                    area=7;NSLog(@"touched here  7 ********************************** ");
                }


            }
            else if (count==8){

                if(angle>-1.40&&angle<=0.45)
                {
                    area=1;
                    NSLog(@"touched here  1 ********************************** ");
                }
                else if(angle>.45&&angle<=.73)
                {
                    area=2;
                    NSLog(@"touched here   2********************************** ");
                }
                else if(angle>.73&&angle<=1.15)
                {
                    area=3;NSLog(@"touched here   3********************************** ");
                }
                else if(angle>1.15&&angle<=1.55){
                    area=4;NSLog(@"touched here  4 ********************************** ");
                }
                else if(angle>-1.55&&angle<=1.95){
                    area=5;NSLog(@"touched here  5 ********************************** ");
                }
                else if(angle>-1.95&&angle<=2.43){
                    area=6;NSLog(@"touched here  6 ********************************** ");
                }
                else if(angle>2.43&&angle<=2.98){
                    area=7;NSLog(@"touched here   7********************************** ");
                }

                //     else if(angle>2.98&&angle<=-1.40){
                else
                {
                    area=8;NSLog(@"touched here  8 ********************************** ");
                }

            } 

Answer 1

更新:添加了完整的工作代码

这里有一些伪代码可以帮助你找出你点击的位置。这是引用最上面的图。 (我假设你的圆心与 View 的中心重合):

(1) 求圆心到接触点的线段方向:

dx = touchPoint.x - circleCenter.x;
dy = touchPoint.y - circleCenter.y;
t = atan2(dy, dx); // some offsetting/direction adjustment might be required

(2) 找出接触点位于哪个八分圆。

octant = floor(4 * t/M_PI); // will return a number between 0 and 7.

如果您的扇区大小不均匀(但您知道每个扇区的角度大小)，您可以使用 if-else 序列。

(3) 右手边的八分圆各有一个“内扇形”和一个环形。如果要测试触摸发生在两个部分中的哪一个，可以先计算触摸点到圆心的距离:

dist = sqrtf(dx * dx + dy * dy);

显然你需要知道每个八分圆的内半径，然后测试

if ( dist < innerRadius[i]) ... // again, you might need to adjust the angle calculations to ensure that the right indices correspond to the right sector. See (working) code below...

innerRadius[8]是一个包含每个八分圆内半径的数组。

这是一些实际的工作代码，它以编程方式生成饼图并正确检测点击位置。只需替换 ViewController.m 的内容即可在“单一 View 应用程序”模板中:

#import "ViewController.h"

static float innerRadii[] = {50, 75, 100, 125, 150, 175, 200, 225};
@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    float side = 600; // square view
    CGPoint center = CGPointMake(side/2, side/2);
    CGFloat radius = side/2 * 0.9;

    UIGraphicsBeginImageContextWithOptions(CGSizeMake(side, side), YES, 0.0);
    UIBezierPath *bgPath = [UIBezierPath bezierPathWithRect:CGRectMake(0, 0, side, side)];
    [[UIColor lightGrayColor] setFill];
    [bgPath fill];
    for (int i = 0; i < 8; i++)
    {
        UIBezierPath *sector = [UIBezierPath bezierPathWithArcCenter:center radius:radius startAngle:M_PI/4 * i endAngle:M_PI/4 * (i+1) clockwise:YES];
        [sector addLineToPoint:center];
        [sector closePath];
#define VAL(x) x/2 + 0.25

        [[UIColor colorWithRed:VAL((float)(i % 2)) green:VAL((float)((i >> 1) % 2)) blue:VAL((float)((i >> 2) % 2)) alpha:1.0] setFill];
        [sector fill];

        UIBezierPath *innerSector = [UIBezierPath bezierPathWithArcCenter:center radius:innerRadii[i] startAngle:M_PI/4 * i endAngle:M_PI/4 * (i+1) clockwise:YES];
        [innerSector addLineToPoint:center];
        [innerSector closePath];
#define VAL1(x) (1- x)/3 + 0.5

        [[UIColor colorWithRed:VAL1((float)(i  % 2)) green:VAL1((float)((i >> 1) % 2)) blue:VAL1((float)((i >> 2) % 2)) alpha:1.0] setFill];
        [innerSector fill];

    }
    UIImage *pieChartImg = UIGraphicsGetImageFromCurrentImageContext();
    UIImageView *pieChartView = [[UIImageView alloc] initWithImage:pieChartImg];
    pieChartView.center = self.view.center;
    [self.view addSubview:pieChartView];

    UITapGestureRecognizer *gr = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(identifyTappedSector:)];
    pieChartView.userInteractionEnabled = YES;
    [pieChartView addGestureRecognizer:gr];
}

- (void)identifyTappedSector:(UITapGestureRecognizer *)tgr
{
    CGPoint touchPoint = [tgr locationInView:tgr.view];
    CGPoint circleCenter = CGPointMake(tgr.view.bounds.size.width/2, tgr.view.bounds.size.height/2);
    float dx = circleCenter.x - touchPoint.x;
    float dy = circleCenter.y - touchPoint.y;
    float t = atan2f(dy, dx) + M_PI;
    NSLog(@"angle = %f", t * 180.0/M_PI);
    int octant = floorf(4 * t/M_PI);

    NSLog(@"You tapped octant number: %d!", octant);
    float dist = sqrtf(dx * dx + dy * dy);
    if (dist <= innerRadii[octant])
        NSLog(@"\tYou tapped the inner sector!");
    else
        NSLog(@"\tYou tapped the annulus!");
}


@end