android - MPAndroidChart:未调用 PieChart onValueSelected

Question

我对饼图有疑问。每次调用 Activity 时，我都会更新图表，我正在这样做:

private void setupPieChart() {
    LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
    mChart.setLayoutParams(params);

    mChart.setUsePercentValues(true);

    /**
     * Hide the Description and the Legend.
     */
    mChart.setDescription("");
    mChart.getLegend().setEnabled(false);

    /**
     * Hole in the middle.
     */
    mChart.setDrawHoleEnabled(true);
    mChart.setHoleRadius(50);
    mChart.setTransparentCircleRadius(55);

    mChart.setRotationAngle(0);
    mChart.setRotationEnabled(true);

    mChart.setOnChartValueSelectedListener(new OnChartValueSelectedListener() {
        @Override
        public void onValueSelected(Entry e, int dataSetIndex, Highlight h) {
            switch (e.getXIndex()) {
                case 0:
                    startLearning(e.getXIndex());
                    break;
                case 1:
                    startLearning(e.getXIndex());
                    break;
                case 2:
                    startLearning(e.getXIndex());
                    break;
                case 3:
                    startLearning(e.getXIndex());
                    break;
                case 4:
                    startLearning(e.getXIndex());
                    break;
                default:
                    break;
            }
        }

        @Override
        public void onNothingSelected() {
            System.out.println("onNothingSelected");
        }
    });

    addDataForPieChart();
}

我正在添加数据:

private void addDataForPieChart() {
    /**
     * Data of the Chart.
     */
    float[] value = mCurrentLearnSet.getCountFromLevel();
    String[] names = {"First Level", "Second Level", "Third Level", "Forth Level", "Fifth Level"};

    /**
     * Create needed Entries.
     */
    List<Entry> entries = new ArrayList<>();
    List<String> strings = new ArrayList<>();
    for (int i = 0; i < value.length; i++) {
        if (value[i] != 0) {
            entries.add(new Entry(value[i], i));
            strings.add(names[i]);
        }
    }

    /**
     * Create pie data set.
     */
    PieDataSet dataSet = new PieDataSet(entries, "Your Progress");
    dataSet.setSliceSpace(3);
    dataSet.setSelectionShift(5);

    /**
     * Setup Colors.
     */
    dataSet.setColors(ColorTemplate.LIBERTY_COLORS);

    /**
     * Instantiate pie data object.
     */
    PieData data = new PieData(strings, dataSet);
    data.setValueFormatter(new PercentFormatter());
    data.setValueTextSize(13f);
    data.setValueTextColor(R.color.primary_text);

    /**
     * Set the Data to the PieChart.
     */
    mChart.setData(data);

    /**
     * Undo all highlights.
     */
    mChart.highlightValues(null);

    /**
     * Update pie chart.
     */
    mChart.notifyDataSetChanged();
    mChart.invalidate();
}

我的问题如下:

图表中每次创建时都有不同数量的切片。 OnChartValueSelectedListener() 有时无法正常工作。切片显示正确，但方法 onValueSelected() 从未被调用，因此我无法单击它们。虽然没有错误或突出显示。只是 onNothingSelected() 被调用。

请指教，我该怎么办？

Answer 1

问题是以下代码段中条目的索引缺失。由于我删除了 if 语句，代码再次正常工作。

/**
 * Create needed Entries.
 */
List<Entry> entries = new ArrayList<>();
List<String> strings = new ArrayList<>();
for (int i = 0; i < value.length; i++) {
    if (value[i] != 0) { // <--
        entries.add(new Entry(value[i], i));
        strings.add(names[i]);
    }
}