如何在IOS8/objective c中解决'Invalid direction in positionRelativeToViewPoint:forCoordinate:inDirection:‘error

Question

我正在使用核心图创建图形.I在日志中有错误

*由于未捕获异常'NSInvalidArgumentException‘而终止应用，原因：’positionRelativeToViewPoint:forCoordinate:inDirection:‘中的方向无效

我正在使用下面的代码来绘制轴

-(void)configureAxesDancis {
    // 1 - Create styles
    CPTMutableTextStyle *axisTitleStyle = [CPTMutableTextStyle textStyle];
    axisTitleStyle.color = [CPTColor blackColor];
    axisTitleStyle.fontName = @"Helvetica-Bold";
    axisTitleStyle.fontSize = 12.0f;
    CPTMutableLineStyle *axisLineStyle = [CPTMutableLineStyle lineStyle];
    axisLineStyle.lineWidth = 2.0f;
    axisLineStyle.lineColor = [CPTColor blackColor];
    CPTMutableTextStyle *axisTextStyle = [[CPTMutableTextStyle alloc] init];
    axisTextStyle.color = [CPTColor whiteColor];
    axisTextStyle.fontName = @"Helvetica-Bold";
    axisTextStyle.fontSize = 11.0f;
    CPTMutableLineStyle *tickLineStyle = [CPTMutableLineStyle lineStyle];
    tickLineStyle.lineColor = [CPTColor blackColor];
    tickLineStyle.lineWidth = 2.0f;
    CPTMutableLineStyle *gridLineStyle = [CPTMutableLineStyle lineStyle];
    tickLineStyle.lineColor = [CPTColor blackColor];
    tickLineStyle.lineWidth = 1.0f;
    // 2 - Get axis set
    CPTXYAxisSet *axisSet = (CPTXYAxisSet *) self.hostView.hostedGraph.axisSet;
    // 3 - Configure x-axis
    CPTAxis *x = axisSet.xAxis;
    x.title = @"Age In Days";
    x.titleTextStyle = axisTitleStyle;
    x.titleOffset = -30.0f;
    x.axisLineStyle = axisLineStyle;
    x.labelingPolicy = CPTAxisLabelingPolicyNone;
    x.labelTextStyle = axisTextStyle;
    x.majorTickLineStyle = axisLineStyle;
    x.majorTickLength = 2.0f;
    x.tickDirection = CPTSignNegative;
   // x.axisConstraints = [CPTConstraints constraintWithLowerOffset:15.0];  //  x.axisConstraints = [CPTConstraints constraintWithLowerOffset:15.0];

    NSInteger majorIncrementx = 5;
    NSInteger minorIncrementx = 1;
    CGFloat xMax = 20.0f;  // should determine dynamically based on max price
    NSMutableSet *xLabels = [NSMutableSet set];
    NSMutableSet *xMajorLocations = [NSMutableSet set];
    NSMutableSet *xMinorLocations = [NSMutableSet set];

    // NSInteger m = 0;
    for (NSInteger j = minorIncrementx; j <= xMax; j += minorIncrementx) {
        NSUInteger mod = j % majorIncrementx;
        if (mod == 0) {
            CPTAxisLabel *label = [[CPTAxisLabel alloc] initWithText:[NSString stringWithFormat:@"%li", (long)j] textStyle:x.labelTextStyle];
            NSDecimal location = CPTDecimalFromInteger(j-10);
            // CGFloat location = m+5;
            label.tickLocation = location;
            label.offset = -x.majorTickLength+10 - x.labelOffset+10;
            if (label) {
                [xLabels addObject:label];
            }
            [xMajorLocations addObject:[NSDecimalNumber decimalNumberWithDecimal:location]];
        } else {
            [xMinorLocations addObject:[NSDecimalNumber decimalNumberWithDecimal:CPTDecimalFromInteger(j)]];
        }
    }
    x.axisLabels = xLabels;
    x.majorTickLocations = xMajorLocations;
    x.minorTickLocations = xMinorLocations;



    // 4 - Configure y-axis
    CPTAxis *y = axisSet.yAxis;
    y.title = @"Width";
    y.titleTextStyle = axisTitleStyle;
    y.titleOffset = 40.0f;
    y.axisLineStyle = axisLineStyle;
    y.majorGridLineStyle = gridLineStyle;
    y.labelingPolicy = CPTAxisLabelingPolicyNone;
    y.labelTextStyle = axisTextStyle;
    y.labelOffset = -10.0f;
    y.majorTickLineStyle = axisLineStyle;
    y.majorTickLength = 4.0f;
    y.minorTickLength = 2.0f;
    y.tickDirection = CPTSignNegative;
    NSInteger majorIncrement = 1000;
    NSInteger minorIncrement = 1000;
    CGFloat yMax = 10000.0f;  // should determine dynamically based on max price
    NSMutableSet *yLabels = [NSMutableSet set];
    NSMutableSet *yMajorLocations = [NSMutableSet set];
    NSMutableSet *yMinorLocations = [NSMutableSet set];
    for (NSInteger j = minorIncrement; j <= yMax; j += minorIncrement) {
        NSUInteger mod = j % majorIncrement;
        if (mod == 0) {
            CPTAxisLabel *label = [[CPTAxisLabel alloc] initWithText:[NSString stringWithFormat:@"%li", (long)j] textStyle:y.labelTextStyle];
            NSDecimal location = CPTDecimalFromInteger(j/3);
            label.tickLocation = location;
            label.offset = -y.majorTickLength - y.labelOffset;
            if (label) {
                [yLabels addObject:label];
            }
            [yMajorLocations addObject:[NSDecimalNumber decimalNumberWithDecimal:location]];
        } else {
            [yMinorLocations addObject:[NSDecimalNumber decimalNumberWithDecimal:CPTDecimalFromInteger(j)]];
        }
    }
    y.axisLabels = yLabels;
    y.majorTickLocations = yMajorLocations;
    y.minorTickLocations = yMinorLocations;

}

当调用此函数时，应用程序崩溃。我不understand.but前几天的代码工作正常，之后我在目标.but中做了一些更改，这是coming.please帮助解释为什么会出现这个错误。谢谢！

添加堆栈跟踪：

 Uncaught exception: Invalid direction in positionRelativeToViewPoint:forCoordinate:inDirection:
 2015-03-30 17:52:19.939 MyApp[4398:101971] Stack trace: (
0   CoreFoundation                      0x0000000103de4f35 __exceptionPreprocess + 165
1   libobjc.A.dylib                     0x0000000103a7dbb7 objc_exception_throw + 45
2   CoreFoundation                      0x0000000103de4e6d +[NSException raise:format:] + 205
3   MyApp                         0x00000001003fa1be -[CPTAxisLabel positionRelativeToViewPoint:forCoordinate:inDirection:] + 1998
4   MyApp                         0x00000001003b9423 -[CPTAxis updateMajorTickLabels] + 675
5   MyApp                         0x00000001003bbc85 -[CPTAxis setAxisLabels:] + 1685
6   MyApp                         0x00000001003065e0 -[MyAppBarChartViewController configureAxes] + 2496
7   MyApp                         0x000000010030477c -[MyAppBarChartViewController initPlot] + 124
8   MyApp                         0x0000000100304285 -[MyAppBarChartViewController viewDidLoad] + 533
9   UIKit                               0x0000000102208a90 -[UIViewController loadViewIfRequired] + 738
10  UIKit                               0x0000000102208c8e -[UIViewController view] + 27
11  UIKit                               0x000000010224be80 -[UITabBarController transitionFromViewController:toViewController:transition:shouldSetSelected:] + 360
12  UIKit                               0x0000000102248069 -[UITabBarController _setSelectedViewController:] + 311
13  UIKit                               0x000000010224b4e9 -[UITabBarController _tabBarItemClicked:] + 245
14  UIKit                               0x00000001020e48be -[UIApplication sendAction:to:from:forEvent:] + 75
15  UIKit                               0x00000001023b8b76 -[UITabBar _sendAction:withEvent:] + 451
16  UIKit                               0x00000001020e48be -[UIApplication sendAction:to:from:forEvent:] + 75
17  UIKit                               0x00000001021eb410 -[UIControl _sendActionsForEvents:withEvent:] + 467
18  UIKit                               0x00000001023bcfd1 -[UITabBar(Static) _buttonUp:] + 103
19  UIKit                               0x00000001020e48be -[UIApplication sendAction:to:from:forEvent:] + 75
20  UIKit                               0x00000001021eb410 -[UIControl _sendActionsForEvents:withEvent:] + 467
21  UIKit                               0x00000001021ea7df -[UIControl touchesEnded:withEvent:] + 522
22  UIKit                               0x000000010212a308 -[UIWindow _sendTouchesForEvent:] + 735
23  UIKit                               0x000000010212ac33 -[UIWindow sendEvent:] + 683
24  UIKit                               0x00000001020f79b1 -[UIApplication sendEvent:] + 246
25  UIKit                               0x0000000102104a7d _UIApplicationHandleEventFromQueueEvent + 17370
26  UIKit                               0x00000001020e0103 _UIApplicationHandleEventQueue + 1961
27  CoreFoundation                      0x0000000103d1a551 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
28  CoreFoundation                      0x0000000103d1041d __CFRunLoopDoSources0 + 269
29  CoreFoundation                      0x0000000103d0fa54 __CFRunLoopRun + 868
30  CoreFoundation                      0x0000000103d0f486 CFRunLoopRunSpecific + 470
31  GraphicsServices                    0x000000010748a9f0 GSEventRunModal + 161
32  UIKit                               0x00000001020e3420 UIApplicationMain + 1282
33  MyApp                         0x00000001001f7075 main + 149
34  libdyld.dylib                       0x0000000104a90145 start + 1

Answer 1

在使用核心图框架构建散点图时，我刚刚遇到了同样的错误。当图形试图更新滚动条标签时，您在主题中提到的相同的NSInvalidArgumentException将被抛出，如堆栈跟踪中要调用的最后四个方法所示(按调用时间按时间顺序显示在下面)：

[MyAppBarChartViewController configureAxes]
[CPTAxis setAxisLabels:]
[CPTAxis updateMajorTickLabels]
[CPTAxisLabel positionRelativeToViewPoint:forCoordinate:inDirection:]

最终导致该问题的原因是将x轴刻度方向设置为负值，如以下行所示：

 x.tickDirection = CPTSignNegative;

将tickDirection更改为CPTSignNone或CPTSignPositive为我解决了这个问题。不知道为什么，我还没有更深入的研究。希望这能有所帮助！