WIP: Add Calendar Month widget

[yvie-k]

Adds a widget that displays a whole month.
You can tap on a day to open the calendar on that day.

Closes #162

Work in progress
Due to #417 I don't know if this will get merged once complete. My phone's API level is 26 and the other widget has worked for me without problems.
It would be good if someone could test whether this has the same problems as the other widget.

Another thing is that I don't know how to get the event data. Therefore if this has the possibility to get merged, I'd hope to get some help on that to implement that functionality.

[Gitsaibot]

Nice that you put work in the widget. If I have time at the weekend, I will test your commit on my phone.

[yvie-k]

Have you had time to check it out yet?

[Gitsaibot]

Today I had a quick look at it ;). First, I can add the widget and it shows up. Like you said it shows no events. Whether the month changes automatically I could not test yet. I need a month change ;)

You can tap on a day to open the calendar on that day.

This did not work if you have a different default view.

[yvie-k]

Thanks for testing it.
The widget should update once every hour. Therefore it might not be immediately updated after midnight, but I haven't tested that behaviour yet.

You can tap on a day to open the calendar on that day.

This did not work if you have a different default view.

How can I force this?
Currently, I use content://com.android.calendar/time/ as the uri to open

[MaxXor]

Any news?

[yvie-k]

@MaxXor I'm still stuck on where to get the event data and how the calendar can be forced to open the day view when clicking on a day.

When I get some help on this I can resume working on it, but unfortunately @Gitsaibot seems to be quite busy. If you can help me or know someone who can, I would really appreciate your help.

[mYnDstrEAm]

This seems to be almost done, could you please add the last bits and merge it?

It looks like events are loaded here; not sure where these events are stored and how to retrieve them from the widget but it's probably very similar to / just like how it's done in the monthview. While it would be nice if one could click on a day in the widget and have the widget open the dayview for that day, that could be implemented at a later point so that now it only opens the monthview.

A months view widget is very important and it seems to be almost implemented.