How to set minimum x-axis interval in iOS chart?

If you want to show only 4 intervals then you can set the label count to 4.

 chartView.xAxis.labelCount = 4

To hide the circle, disable the drawCircleEnabled for ChratDataSet

chartDataSet.drawCirclesEnabled = false

To set the minimum of the axis you need to set the customAxisMin property of the axis.

For example in swift:

lineChartView.leftAxis.customAxisMin = 0

To remove the circle you have to set the drawCirclesEnabled property to false on your LineChartDataSet

For the dot, disable dataSet.isDrawCirclesEnabled.

For the range, check below out. BTW, you have to understand that because you have 7 x axis values, it will draw every one of it by default. If you want fine-grained control, you need to change the renderer logic.

You can set the max range is 4, so only 4 x axis values will be displayed, otherwise you should only pass 4 data values into the chart.

/// Sets the size of the area (range on the x-axis) that should be maximum visible at once (no further zomming out allowed).
/// If this is e.g. set to 10, no more than 10 values on the x-axis can be viewed at once without scrolling.
public func setVisibleXRangeMaximum(maxXRange: CGFloat)
{
    let xScale = _deltaX / maxXRange
    _viewPortHandler.setMinimumScaleX(xScale)
}

/// Sets the size of the area (range on the x-axis) that should be minimum visible at once (no further zooming in allowed).
/// If this is e.g. set to 10, no less than 10 values on the x-axis can be viewed at once without scrolling.
public func setVisibleXRangeMinimum(minXRange: CGFloat)
{
    let xScale = _deltaX / minXRange
    _viewPortHandler.setMaximumScaleX(xScale)
}