Customize the marker - MPAndroidChart

https://github.com/PhilJay/MPAndroidChart/blob/master/MPChartExample/src/main/res/drawable-nodpi/marker2.png

Using an image as a background

That's it...

That's it??!!!

Instead of the background colour 'Red', I've used this image to get that arrow.

Make sure you have the latest version MPAndroidChart (3.0.1). Clone, build, and run the sample project on your device. You can see that the first example on the menu called "Line Chart - a simple demonstration of the linechart" has the highlight view you want. It looks like this:

The code is inside the sample project in LineChartActivity1. The xml is the following:

    <TextView
        android:id="@+id/tvContent"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="7dp"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:text=""
        android:textSize="12dp"
        android:textColor="@android:color/white"
        android:ellipsize="end"
        android:singleLine="true"
        android:textAppearance="?android:attr/textAppearanceSmall" />

</RelativeLayout>

The MarkerView is as follows:

package com.xxmassdeveloper.mpchartexample.custom;

import android.content.Context;
import android.widget.TextView;

import com.github.mikephil.charting.components.MarkerView;
import com.github.mikephil.charting.data.CandleEntry;
import com.github.mikephil.charting.data.Entry;
import com.github.mikephil.charting.highlight.Highlight;
import com.github.mikephil.charting.utils.MPPointF;
import com.github.mikephil.charting.utils.Utils;
import com.xxmassdeveloper.mpchartexample.R;

/**
 * Custom implementation of the MarkerView.
 *
 * @author Philipp Jahoda
 */
public class MyMarkerView extends MarkerView {

    private TextView tvContent;

    public MyMarkerView(Context context, int layoutResource) {
        super(context, layoutResource);

        tvContent = (TextView) findViewById(R.id.tvContent);
    }

    // callbacks everytime the MarkerView is redrawn, can be used to update the
    // content (user-interface)
    @Override
    public void refreshContent(Entry e, Highlight highlight) {

        if (e instanceof CandleEntry) {

            CandleEntry ce = (CandleEntry) e;

            tvContent.setText("" + Utils.formatNumber(ce.getHigh(), 0, true));
        } else {

            tvContent.setText("" + Utils.formatNumber(e.getY(), 0, true));
        }

        super.refreshContent(e, highlight);
    }

    @Override
    public MPPointF getOffset() {
        return new MPPointF(-(getWidth() / 2), -getHeight());
    }
}

And it is consumed like this:

MyMarkerView mv = new MyMarkerView(this, R.layout.custom_marker_view);
mv.setChartView(mChart); // For bounds control