核心情节:只适用于三个情节

Question

我在我的应用程序(iGear)中添加了一个散点图，所以当用户选择一个、两个或三个链环与自行车上的一个齿轮组相结合时，线将显示齿轮表。

问题是，核心图仅在选择三个链环时才显示这些图。我需要你的帮助，这是我在核心情节的第一次尝试，我迷路了。

我的代码如下：

iGearMainViewController.m

- (IBAction)showScatterIpad:(id)sender {
cogsetToPass = [NSMutableArray new];
arrayForChainringOne = [NSMutableArray new];
arrayForChainringTwo = [NSMutableArray new];
arrayForChainringThree = [NSMutableArray new];
//behavior according to number of chainrings
switch (self.segmentedControl.selectedSegmentIndex) {

    case 0: // one chainring selected

        for (int i = 1; i<= [cassette.numCogs intValue]; i++) {
            if (i <10) {
                corona = [NSString stringWithFormat:@"cog0%d",i];

            }else {
                corona = [NSString stringWithFormat:@"cog%d",i];
            }
            float one = (wheelSize*[_oneChainring.text floatValue]/[[cassette valueForKey:corona]floatValue])/1000;
            float teeth = [[cassette valueForKey:corona] floatValue];
            [cogsetToPass addObject:[NSNumber numberWithFloat:teeth]];
            [arrayForChainringOne addObject:[NSNumber numberWithFloat:one]];
        }
            break;
     case 1: // two chainrings selected

        for (int i = 1; i<= [cassette.numCogs intValue]; i++) {
            if (i <10) {
                corona = [NSString stringWithFormat:@"cog0%d",i];

            }else {
                corona = [NSString stringWithFormat:@"cog%d",i];
            }
            float one = (wheelSize*[_oneChainring.text floatValue]/[[cassette valueForKey:corona]floatValue])/1000;
            //NSLog(@" gearsForOneChainring = %@",[NSNumber numberWithFloat:one]);
            float two = (wheelSize*[_twoChainring.text floatValue]/[[cassette valueForKey:corona]floatValue])/1000;
            [cogsetToPass addObject:[NSNumber numberWithFloat:[[cassette valueForKey:corona]floatValue]]];
            [arrayForChainringOne addObject:[NSNumber numberWithFloat:one]];
            [arrayForChainringTwo addObject:[NSNumber numberWithFloat:two]];
        }
        break;
    case 2: // three chainrings selected
        for (int i = 1; i<= [cassette.numCogs intValue]; i++) {
            if (i <10) {
                corona = [NSString stringWithFormat:@"cog0%d",i];

            }else {
                corona = [NSString stringWithFormat:@"cog%d",i];
            }
            float one = (wheelSize*[_oneChainring.text floatValue]/[[cassette valueForKey:corona]floatValue])/1000;
            float two = (wheelSize*[_twoChainring.text floatValue]/[[cassette valueForKey:corona]floatValue])/1000;
            float three = (wheelSize*[_threeChainring.text floatValue]/[[cassette valueForKey:corona]floatValue])/1000;
            [cogsetToPass addObject:[cassette valueForKey:corona]];
            [arrayForChainringOne addObject:[NSNumber numberWithFloat:one]];
            [arrayForChainringTwo addObject:[NSNumber numberWithFloat:two]];
            [arrayForChainringThree addObject:[NSNumber numberWithFloat:three]];

        }
    default:
        break;
}

ScatterIpadViewController *sivc = [[ScatterIpadViewController alloc]initWithNibName: @"ScatterIpadViewController" bundle:nil];
[sivc setModalTransitionStyle:UIModalTransitionStyleFlipHorizontal];
    sivc.records = [cassetteNumCogs integerValue];
    sivc.cogsetSelected = self.cogsetToPass;
    sivc.chainringOne = self.arrayForChainringOne;
    sivc.chainringThree = self.arrayForChainringThree;
    sivc.chainringTwo = self.arrayForChainringTwo;
    [self presentViewController:sivc animated:YES completion:nil];

}

和带有代码绘制情节的子视图：

ScatterIpadViewController.m

    #pragma mark - CPTPlotDataSource methods

- (NSUInteger)numberOfRecordsForPlot: (CPTPlot *)plot {
    return records;
}

- (NSNumber *)numberForPlot: (CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index{
    switch (fieldEnum)
    {
        case CPTScatterPlotFieldX:
            return [NSNumber numberWithInt:index];
        break;

    case CPTScatterPlotFieldY:{

        if ([plot.identifier isEqual:@"one"]==YES) {
            //NSLog(@"chainringOne objectAtIndex:index = %@", [chainringOne objectAtIndex:index]);
            return [chainringOne objectAtIndex:index];
        }else if ([plot.identifier isEqual:@"two"] == YES ){
            //NSLog(@"chainringTwo objectAtIndex:index = %@", [chainringTwo objectAtIndex:index]);
            return [chainringTwo objectAtIndex:index];

        }else if ([plot.identifier isEqual:@"three"] == YES){
            //NSLog(@"chainringThree objectAtIndex:index = %@", [chainringThree objectAtIndex:index]);
            return  [chainringThree objectAtIndex:index];

        }

    default:
        break;
        }
  }
  return nil;
}

返回的错误是尝试访问空数组时的异常。

2012-15 11:02:42.962 iGearScatter3283:11603 iGearScatter3283:11603终止应用程序

谢谢!

Answer 1

解决了！我骑自行车时看到了灯。

- (NSNumber *)numberForPlot: (CPTPlot *)plot field:(NSUInteger)fieldEnum recordIndex:(NSUInteger)index{

    if (([chainringOne count]!=0) && ([chainringTwo count]==0) && ([chainringThree count]==0)) {
        switch (fieldEnum) {
            case CPTScatterPlotFieldX:
                 return [NSNumber numberWithInt:(index+1)];
                break;

            case CPTScatterPlotFieldY:{
                if ([plot.identifier isEqual:@"one"]) {
                    return [chainringOne objectAtIndex:index];
                }
            }
            default:
            break;
        }
    }else if (([chainringOne count]!=0) && ([chainringTwo count]!=0) && ([chainringThree count]==0)){
        switch (fieldEnum) {
            case CPTScatterPlotFieldX:
                return [NSNumber numberWithInt:(index+1)];
                break;
            case CPTScatterPlotFieldY:{
                if ([plot.identifier isEqual:@"one"]) {
                     return [chainringOne objectAtIndex:index];
                }else if ([plot.identifier isEqual:@"two"]){
                    return [chainringTwo objectAtIndex:index];
                }
            }
            default:
            break;
        }
    }else if (([chainringOne count]!=0) && ([chainringTwo count]!=0) && ([chainringThree count]!= 0)){
        switch (fieldEnum) {
            case CPTScatterPlotFieldX:
                return [NSNumber numberWithInt:(index+1)];
                break;
            case CPTScatterPlotFieldY:{
                if (([chainringOne count] !=0) && ([plot.identifier isEqual:@"one"])) {
                    return [chainringOne objectAtIndex:index];
        }else if ((chainringTwo || chainringTwo.count) &&([plot.identifier isEqual:@"two"] == YES )){
              return [chainringTwo objectAtIndex:index];

         }else if ((chainringThree || chainringTwo.count)&& ([plot.identifier isEqual:@"three"] == YES)){
                return  [chainringThree objectAtIndex:index];
            }
        default:
            break;
            }
        }
    }
    return nil;
}