Android Question Placing markers on a graph

[DT1111]

I want to place a few markers (triangle, diamond, square, round markers) on a graph curve and I am using the chart framework found at the following link to plot the graph

https://www.b4x.com/android/forum/threads/android-charts-framework.8260/

I would like to know how to place these markers on the graph. Thanks.

 

[klaus]

You must draw them yourself onto the chart.
You can do it in your code or add a new sub to the Charts module.

What defines the position of the markers ?

 

[DT1111]

Hi Klaus

For a start I am using a simple y= mx to plot a straight line where x = 0 to 100 and then place

a triangle marker at x = 10
a circle marker at x = 25
a square marker at x = 50
a diamond marker at x = 65

Conceptually I am thinking of creating a canvas and then use special character symbol which has the above shapes and place them ontop of the y=mx line. But I think there is a more noble way of doing it.

Please recommend or if there is already a similar attempt on the forum, please let me know. Thanks!

 

[klaus]

You don't need to define a new Canvas you already have one LD.Canvas.
I would not use special characters but DrawCircle, DrawRect and DrawPath for the two others.

 

[DT1111]

Thanks Klaus

Not sure if this is a new thread but it is related to the above topic.

How can a balloon of text be placed next to a marker. The balloon adds information related to a particular marker on the graph.

 

[klaus]

You need to do it on your own.
Do you want the balloon to remain on the chart or do you want to remove it also ?
If it remains you can draw it directly onto the chart, otherwise you could add a transparent Panel as a layer and draw onto this one.
To remove the balloon you can either remove the Panel, set it to invisible or redraw it transparent.

 

[DT1111]

The intention is to make the balloon or callout appears when the marker is touched and then disappear when the balloon is touched.

Placing a marker is not a problem but creating a balloon similar to the pic, I am unclear how best to approach it esp the size of balloon changes as it wraps around some text of varied length.

Any guidance is appreciated.

 

[klaus]

For the baloons you may have a look at this:
[Class] Baloon labels
You may also have a look at this, I haven't used it:
MPAndroidCharts - Various type of graphs / charts

 

[DT1111]

Thanks very much Klaus and they look promising.