android - 如何在MPAndroidCharts xAxis标签中添加背景？

我想在图表行的x轴标签上添加背景色，并将y轴放在网格线上，如屏幕截图所示。在不定制库的情况下实现这一点是可能的吗？

最佳答案

我不想破坏这个库，所以我不得不扩展一些类并重写一些方法来满足我的需求。我所做的如下：
扩展Xaxis类并重写：

private int mXAxisLabelBackgroundColor = Color.argb(200, 140, 234, 255);
/**
 * boolen used to enable or disable label background, default is enabled
 */
private boolean mEnableLabelBackground = false;


public CustomXAxis(){
    super();
}

public void setLabelBackgroundColor(int color){
    mXAxisLabelBackgroundColor = color;
}

public void setLabelBackgroundColor(String colorHex){
    mXAxisLabelBackgroundColor = Color.parseColor(colorHex);
}

public int getXAxisLabelBackgroundColor(){
    return mXAxisLabelBackgroundColor;
}

/**
 * Enable/disable X Axis label background, default is disabled.
 * @param enable
 */
public void setDrawLabelBackground(boolean enable){
    mEnableLabelBackground = enable;
}

/**
 *
 * @return boolean true if drawing label background is enabled otherwise false
 */
public boolean isDrawLabelBackgroundEnabled(){
    return mEnableLabelBackground;
}

扩展xaxisRenderer并覆盖DrawLabels（画布C，浮点位置）。在画标签之前画一个矩形。

        if (((CustomXAxis)mXAxis).isDrawLabelBackgroundEnabled()) {
           drawLabelBackground(c);
        }

扩展yaxis，只需添加一个访问器和mutator来设置网格线上下的yaxis标签。

private float mYLabelPosition = 0f;

public CustomYAxisRight(){
    super(AxisDependency.RIGHT);
}

/**
 * Sets the label position above or below the gridline.
 * <p>use negative number to set label position above gridline.</p>
 * @param position
 */
public void setYLabelPosition(float position){
    mYLabelPosition = position;
}

public float getYLabelPosition(){
    return mYLabelPosition;
}

扩展YaxisRenderer并覆盖DrawyLabels（画布C，float fixedPosition，float[]位置，float offset）

c.drawText(text, fixedPosition, positions[i * 2 + 1] + (offset+((CustomYAxisRight)mYAxis).getYLabelPosition()), mAxisLabelPaint);

我还想在图表从0开始时显示Y轴标签0的网格线。
覆盖renderGridlines（画布C）并在绘制其他线之前绘制一条线。

if (mYAxis.isStartAtZeroEnabled()) {
        mTrans.pointValuesToPixel(position);
        gridLinePath.moveTo(mViewPortHandler.offsetLeft(), mViewPortHandler.contentBottom() - 1f);
        gridLinePath.lineTo(mViewPortHandler.contentRight(), mViewPortHandler.contentBottom() - 1f);
        // draw a path because lines don't support dashing on lower android versions
        c.drawPath(gridLinePath, mGridPaint);
        gridLinePath.reset();
    }

最后扩展线条图并覆盖：

    @Override
protected void init() {
    super.init();
    mAxisRight = new CustomYAxisRight();
    mXAxis = new CustomXAxis();
    mAxisRendererRight = new CustomYAxisRenderer(mViewPortHandler,mAxisRight,mRightAxisTransformer);
    mXAxisRenderer = new CustomXAxisRenderer(mViewPortHandler, mXAxis, mLeftAxisTransformer);
}

@Override
public void setViewPortOffsets(final float left, final float top, final float right, final float bottom) {
    mCustomViewPortEnabled = true;
    if (((CustomXAxis)mXAxis).isDrawLabelBackgroundEnabled()){
        if (bottom == 0){
            //we have to leave a space for the labels to draw
            _bottomOffset = 80f;
        }
    }
    post(new Runnable() {

        @Override
        public void run() {

            mViewPortHandler.restrainViewPort(left, top, right, _bottomOffset);
            prepareOffsetMatrix();
            prepareValuePxMatrix();
        }
    });
}