How to change x value

[tuantmdev]

I'm using stack bar chart view but when upgrade to Chart 3.0.0, i don't know how to update x value anymore

Here the code

NSMutableArray *yVals = [[NSMutableArray alloc] init];

    for (int i = 0; i < 3; i++)
    {
        double mult = 4;
        double val1 = (double) (arc4random_uniform(mult) + mult / 3);
        double val2 = (double) (arc4random_uniform(mult) + mult / 3);
        double val3 = (double) (arc4random_uniform(mult) + mult / 3);

        [yVals addObject:[[BarChartDataEntry alloc] initWithX:i yValues:@[@(val1), @(val2), @(val3)]]];
    }

    BarChartDataSet *set1 = nil;
    if (_chartView.data.dataSetCount > 0)
    {
        set1 = (BarChartDataSet *)_chartView.data.dataSets[0];
        set1.values = yVals;
        [_chartView.data notifyDataChanged];
        [_chartView notifyDataSetChanged];
    }
    else
    {
        set1 = [[BarChartDataSet alloc] initWithValues:yVals label:@"Statistics Vienna 2014"];
        set1.colors = @[ChartColorTemplates.material[0], ChartColorTemplates.material[1], ChartColorTemplates.material[2]];
        set1.stackLabels = @[@"Births", @"Divorces", @"Marriages"];

        NSMutableArray *dataSets = [[NSMutableArray alloc] init];
        [dataSets addObject:set1];

        NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
        formatter.maximumFractionDigits = 1;
        formatter.negativeSuffix = @" $";
        formatter.positiveSuffix = @" $";

        BarChartData *data = [[BarChartData alloc] initWithDataSets:dataSets];
        [data setValueFont:[UIFont fontWithName:@"HelveticaNeue-Light" size:7.f]];
        [data setValueFormatter:[[ChartDefaultValueFormatter alloc] initWithFormatter:formatter]];
        [data setValueTextColor:UIColor.whiteColor];

        _chartView.fitBars = YES;
        _chartView.data = data;
    }