MPAndroidChart MarkerView 点击事件

一直以来，图标类UI都用MPAndroidChart这个库，但是今天今天感觉不好了，想实现一个标签，并可点击，我以为这玩意肯定支持，结果在库里找了好久，发现没有，然后我的第一想法就是，这玩意要重写touch，然后处理一些逻辑。 but，我还是到源码里找了一圈还是木有，想这个需求应该不是很古怪，就到issues里see see，果然有！！！Make MarkerView Click
不出我所料。

1. 继承LineChart（其他chart也可），转移touch事件

public class MyChart extends LineChart {
    
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        boolean handled = true;
        // if there is no marker view or drawing marker is disabled
        if (isShowingMarker() && this.getMarker() instanceof ChartInfoMarkerView){
        // 
            ChartMarkerView markerView = (ChartMarkerView) this.getMarker();
            Rect rect = new Rect((int)markerView.drawingPosX,(int)markerView.drawingPosY,(int)markerView.drawingPosX + markerView.getWidth(), (int)markerView.drawingPosY + markerView.getHeight());
            if (rect.contains((int) event.getX(),(int) event.getY())) {
                // touch on marker -> dispatch touch event in to marker
                markerView.dispatchTouchEvent(event);
            }else{
                handled = super.onTouchEvent(event);
            }
        }else{
            handled = super.onTouchEvent(event);
        }
        return handled;
    }

    private boolean isShowingMarker(){
        return mMarker != null && isDrawMarkersEnabled() && valuesToHighlight();
    }
}

1. 自定义MarkerView，接管点击事件

public class ChartMarkerView extends MarkerView {
    @BindView(R.id.markerview_root)
    LinearLayout markerContainerView;
    
    protected float drawingPosX;
    protected float drawingPosY;
    private static final int MAX_CLICK_DURATION = 500;
    private long startClickTime;
	private MarkerViewClickCB cb;

    public void setMarkerViewClickCB(MarkerViewClickCB cb) {
        this.cb = cb;
    }
    public ChartInfoMarkerView(Context context, int layoutResource) {
        super(context, layoutResource);
        ButterKnife.bind(this);
        markerContainerView.setClickable(true);
        markerContainerView.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (cb != null) cb.onMarkerViewClick();
            }
        });
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN: {
                startClickTime = Calendar.getInstance().getTimeInMillis();
                break;
            }
            case MotionEvent.ACTION_UP: {
                long clickDuration = Calendar.getInstance().getTimeInMillis() - startClickTime;
                if(clickDuration < MAX_CLICK_DURATION) {
                    markerContainerView.setOnClickListener(new OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            if (cb != null) cb.onMarkerViewClick();
                        }
                    });
                }
            }
        }
        return super.onTouchEvent(event);
    }

    @Override
    public void draw(Canvas canvas, float posX, float posY) {
        super.draw(canvas, posX, posY);
        MPPointF offset = getOffsetForDrawingAtPoint(posX, posY);
        this.drawingPosX = posX + offset.x;
        this.drawingPosY = posY + offset.y;
    }
}

1. 自定义接口，回调点击事件到合适的地方

public interface MarkerViewClickCB {
    void onMarkerViewClick();
}