Question

我创建了2个单独的图，现在我想检测用户何时更改其中一个（滚动）的xRange并更改第二个图的xRange。

我一直在尝试使用plotSpace:willChangePlotRangeTo:forCoordinate:并在userInfo中发布带有新范围和plotID的通知。父viewController侦听通知并更改第二个绘图的xRange，但是：我收到滞后，第二个情节是＆＃34;摇摇欲坠＆＃34;而且它经常以不同的范围结束。当我这么快的时候，没有观察到颤抖（只有滞后）。

我该如何解决这个问题？你可以在这里看到它： https://www.youtube.com/watch?v=f6VR7rRBuCU&feature=youtu.be

在parentViewController中：

 -(void)receivedNewRangeNotif:(NSNotification*)notification {
    NSDictionary* userInfo = notification.userInfo;
    NSString* identifier = [userInfo objectForKey:@"identifierKey"];
    CPTPlotRange* newRange = [userInfo objectForKey:@"newRangeKey"];

    NSLog(@"receivedNewRangeNotif: %@",identifier);
    if ([identifier isEqualToString:@"firstItemID"]) {
        _secondItem.postNotifications = NO;
        CPTXYPlotSpace *secondPlotSpace = (CPTXYPlotSpace *)_secondItem.graph.defaultPlotSpace;
        secondPlotSpace.xRange = [CPTPlotRange plotRangeWithLocation:newRange.location length:newRange.length];
        _secondItem.postNotifications = YES;
    }
    else if ([identifier isEqualToString:@"secondItemID"]) {
        _firstItem.postNotifications = NO;
    CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)_firstItem.graph.defaultPlotSpace;
    plotSpace.xRange = [CPTPlotRange plotRangeWithLocation:newRange.location length:newRange.length];
        _firstItem.postNotifications = YES;
    }

在plotItem中：

- (CPTPlotRange *)plotSpace:(CPTPlotSpace *)space willChangePlotRangeTo:(CPTPlotRange *)newRange forCoordinate:(CPTCoordinate)coordinate {
    if (_postNotifications) {   
        NSDictionary *userInfo = [[NSDictionary alloc] initWithObjectsAndKeys:newRange, @"newRangeKey",
                                  self.identifier, @"identifierKey", nil];

        NSLog(@"sendingNewRangeNotif");
        [[NSNotificationCenter defaultCenter] postNotificationName:@"TODOnotifRangeChanged" object:nil userInfo:userInfo];
    }
    //DLog(@"changing plotRange");

    //disables possibility to change y size
    if (CPTCoordinateY == coordinate) {
        return [self automaticYRangeWithCustomMinY:_customMinY CustomMaxY:_customMaxX customLengthY:_customYLength];

    }
    //length of range is specified, one can change only the startpoint
    else if (CPTCoordinateX == coordinate) {
        CPTPlotRange* plotRange = [CPTPlotRange plotRangeWithLocation:newRange.location length:_customXLength];
        return plotRange;
    }

    //returning nil is never reached :D
    return nil;
}

编辑：我所观察到的是，当仅在x中非常准确地滚动时，这些图表正在很好地移动。只有当一个人也在Y（甚至是单个像素）中滚动时，它才开始摇晃。

Answer 1

好的，我已经通过更改发送通知的时刻解决了这个问题：

- (CPTPlotRange *)plotSpace:(CPTPlotSpace *)space willChangePlotRangeTo:(CPTPlotRange *)newRange forCoordinate:(CPTCoordinate)coordinate {
        NSLog(@"changing plotRange: %ld",(long)coordinate);
    if (CPTCoordinateY == coordinate) {
        return [self automaticYRangeWithCustomMinY:_customMinY CustomMaxY:_customMaxY customLengthY:_customYLength];
    }
    else if (CPTCoordinateX == coordinate) {
        if (_postNotifications) {

            NSDictionary *userInfo = [[NSDictionary alloc] initWithObjectsAndKeys:newRange, @"newRangeKey",
                                      self.identifier, @"identifierKey", nil];

            NSLog(@"sendingNewRangeNotif");
            [[NSNotificationCenter defaultCenter] postNotificationName:@"TODOnotifRangeChanged" object:nil userInfo:userInfo];
        }

        CPTPlotRange* plotRange = [CPTPlotRange plotRangeWithLocation:newRange.location length:_customXLength];
        return plotRange;
    }

    return nil;
}

CorePlot - 2个图的同步范围

1 个答案: