Android graphview Library and Proguard

If you are using GraphView inside your Android apps, make sure to exclude it from being obfuscated by your proguard config.
I recently changed my app Battery Temperature Guard. I do not use AndroidPlot anymore as a diagram. Instead I use Graphview. Its a cool library to quickly build scaleable and scrollable diagrams.

Everything worked great, but after I released my apps I noticed that scaling by pinch & zoom did not work anymore.
Logcat showed the logs below. By adding this simple line to my proguard.cfg I managed to exclude the graphview classes and packages from being obfuscated by proguard.

-keep class com.jjoe64.graphview.** { *; }

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at android.view.Choreographer.doCallbacks(Choreographer.java:574)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at android.view.Choreographer.doFrame(Choreographer.java:542)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at android.os.Handler.handleCallback(Handler.java:733)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at android.os.Handler.dispatchMessage(Handler.java:95)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at android.os.Looper.loop(Looper.java:136)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at android.app.ActivityThread.main(ActivityThread.java:5017)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at java.lang.reflect.Method.invoke(Native Method)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)

01-03 18:16:17.015    7626-7626/? W/System.err﹕ at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)

01-03 18:16:17.025    7626-7626/? W/System.err﹕ java.lang.NullPointerException: null receiver

01-03 18:16:17.025    7626-7626/? W/System.err﹕ at java.lang.reflect.Method.invoke(Native Method)

01-03 18:16:17.025    7626-7626/? W/System.err﹕ at com.jjoe64.graphview.a.b.a(SourceFile:91)

01-03 18:16:17.025    7626-7626/? W/System.err﹕ at com.jjoe64.graphview.c.onTouchEvent(SourceFile:199)

01-03 18:16:17.025    7626-7626/? W/System.err﹕ at android.view.View.dispatchTouchEvent(View.java:7706)

01-03 18:16:17.025    7626-7626/? W/System.err﹕ at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2216)

01-03 18:16:17.025    7626-7626/? W/System.err﹕ at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:1959)

01-03 18:16:17.025    7626-7626/? W/System.err﹕ at android.v

Changing the icon size in a DraggableGridView

I love DraggableGridView. It's easy to use and looks really nice. I use it in one of my apps, called the DSO-Timer.

But there is one small thing, that bothers me. I couldn't find a way to customize the size of the icons.

So I emailed Thomas Quinn and asked him. A few hours later I received his answer:

Easily done. Just change this section of code in onLayout(...):

        //determine number of columns, at least 2
        colCount = 2;
        int sub = 240;
        w -= 280;
        while (w > 0)
        {
                colCount++;
                w -= sub;
                sub += 40;
        }

To something way simpler, like this:

        //determine number of columns for 50dp children
        colCount = w / 50;

This is the code where the size of the icons is calculated. After playing a bit around in the code, I ended up with this: