MPAndroidChart：我可以为 x 轴标签设置不同的颜色吗？

Question

所以我希望能够在我的条形图中选择一个条形，当我选择一个条形时，它会改变条形的颜色（我知道怎么做），同时也会改变相应 x 的颜色-轴标签。有没有办法做到这一点，如果可以，有人可以帮助我吗？

Answer 1

是的，可以为 xAxis 标签设置不同的颜色。您将不得不使用自定义渲染器，如下所示：

import android.graphics.Canvas;

import com.github.mikephil.charting.components.XAxis;
import com.github.mikephil.charting.renderer.XAxisRenderer;
import com.github.mikephil.charting.utils.MPPointF;
import com.github.mikephil.charting.utils.Transformer;
import com.github.mikephil.charting.utils.Utils;
import com.github.mikephil.charting.utils.ViewPortHandler;

import java.util.Collections;
import java.util.List;

/**
 * Created by rawsond on 29/01/17.
 */

public class ColoredLabelXAxisRenderer extends XAxisRenderer {

    List<Integer> labelColors;

    public ColoredLabelXAxisRenderer(ViewPortHandler viewPortHandler, XAxis xAxis, Transformer trans) {
        super(viewPortHandler, xAxis, trans);
        labelColors = Collections.EMPTY_LIST;
    }

    public ColoredLabelXAxisRenderer(ViewPortHandler viewPortHandler, XAxis xAxis, Transformer trans, List<Integer> colors) {
        super(viewPortHandler, xAxis, trans);
        this.labelColors = colors;
    }

    @Override
    protected void drawLabels(Canvas c, float pos, MPPointF anchor) {
        final float labelRotationAngleDegrees = mXAxis.getLabelRotationAngle();
        boolean centeringEnabled = mXAxis.isCenterAxisLabelsEnabled();

        float[] positions = new float[mXAxis.mEntryCount * 2];

        for (int i = 0; i < positions.length; i += 2) {

            // only fill x values
            if (centeringEnabled) {
                positions[i] = mXAxis.mCenteredEntries[i / 2];
            } else {
                positions[i] = mXAxis.mEntries[i / 2];
            }
        }

        mTrans.pointValuesToPixel(positions);

        for (int i = 0; i < positions.length; i += 2) {

            float x = positions[i];

            if (mViewPortHandler.isInBoundsX(x)) {

                String label = mXAxis.getValueFormatter().getFormattedValue(mXAxis.mEntries[i / 2], mXAxis);
                int color = getColorForXValue(mXAxis.mEntries[i / 2]); //added

                mAxisLabelPaint.setColor(color);

                if (mXAxis.isAvoidFirstLastClippingEnabled()) {

                    // avoid clipping of the last
                    if (i == mXAxis.mEntryCount - 1 && mXAxis.mEntryCount > 1) {
                        float width = Utils.calcTextWidth(mAxisLabelPaint, label);

                        if (width > mViewPortHandler.offsetRight() * 2
                                && x + width > mViewPortHandler.getChartWidth())
                            x -= width / 2;

                        // avoid clipping of the first
                    } else if (i == 0) {

                        float width = Utils.calcTextWidth(mAxisLabelPaint, label);
                        x += width / 2;
                    }
                }

                drawLabel(c, label, x, pos, anchor, labelRotationAngleDegrees);
            }
        }
    }

    private int getColorForXValue(int index) {
        if (index >= labelColors.size()) return mXAxis.getTextColor();

        if (index < 0) return mXAxis.getTextColor();

        return labelColors.get(index);
    }
}

像这样消费它：

mChart.setXAxisRenderer(new ColoredLabelXAxisRenderer(mChart.getViewPortHandler(), mChart.getXAxis(), mChart.getTransformer(AxisDependency.LEFT), colors));

其中colors 是已解析颜色的List<Integer>（不是资源ID），其大小与IDataSet 中的条目数相同。由于您已经知道如何更改高亮条的颜色，所以这部分取决于您。只需像平常一样操作colors。这是一个示例输出：