如何创建 ArrayList<barentry> 使用数组<integer> ?</integer></barentry>

Question

How to implement the interface for displaying a graph with data from SQLlite?

 List<Integer> WaterSpentArrayList;
WaterSpentArrayList = db.getWaterSpent();
    ArrayList<BarEntry> EntryData = new ArrayList<>();
    if ( WaterSpentArrayList.size()==0) {
    }else {
        for (int i = 0; i < WaterSpentArrayList.size(); i++) {
            EntryData.add(new BarEntry(WaterSpentArrayList.get(i), i));
        }
        Log.e(TAG, "Data:  " + EntryData);
        BarDataSet bardataset = new BarDataSet(EntryData, "WaterSpentArrayList");
        BarData data = new BarData((IBarDataSet) DataTimeSpentArrayList, bardataset);
        barChart.setData(data);here

I put values of List and these number to ArrayList but this leads to an error, it does not allow to draw a graph...

E/CleanersActivity: SimpleEntry: [Entry, x: 20.0 y: 0.0, Entry, x: 29.0 y: 1.0, Entry, x: 35.0 y: 2.0, Entry, x: 22.0 y: 3.0, Entry, x: 20.0 y: 4.0, Entry, x: 29.0 y: 5.0, Entry, x: 35.0 y: 6.0, Entry, x: 22.0 y: 7.0, Entry, x: 20.0 y: 8.0, Entry, x: 29.0 y: 9.0, Entry, x: 35.0 y: 10.0, Entry, x: 22.0 y: 11.0, Entry, x: 20.0 y: 12.0, Entry, x: 29.0 y: 13.0, Entry, x: 35.0 y: 14.0, Entry, x: 22.0 y: 15.0] D/AndroidRuntime: Shutting down VM --------- beginning of crash E/AndroidRuntime: FATAL EXCEPTION: main Process: PID: 28873 java.lang.RuntimeException: Unable to start activity ComponentInfo{CleanersActivity}: java.lang.ClassCastException: java.util.ArrayList cannot be cast to com.github.mikephil.charting.interfaces.datasets.IBarDataSet

Which is the best way to plot this data?

Answer 1

BarData data = new BarData((IBarDataSet) DataTimeSpentArrayList, bardataset);

This code seems giving the error. Here bardataset is already the same type with IBarDataSet. So the type of DataTimeSpentArrayList is not compatible with IBarDataSet.

In addition, i would suggest you to use if ( WaterSpentArrayList.size().=0) instead of if ( WaterSpentArrayList.size()==0) { }else. Also using a variable for WaterSpentArrayList.size() is the best practice since the program has to calculate the size value every time checking the condition.