Ghoscher's Blog

Welcome to the fourth part of my tutorial on how to create a map app for Android without using Google™ APIs :).

Series outline:

• Series aim.
• Theory you need to know.
• App design.
• Writing a TilesManager.
• Writing a TilesProvider.
• Seeing results with MapView.
• Adding web support.
• Creating MapView in XML.
• Extra: Fuchs Maps.

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So now we have a TilesManager to do all the math for us & provide us with tile indices, we still need something to give us the actual images of the tiles, this is what TilesProvider does each time our MapView asks for tiles images the TilesProvider will load the data from the Database then return them to the MapView.

Each time we need to get our tiles images we fetch the data from the map database and convert the data into a Bitmap that can be rendered in our MapView, querying the database is relatively a slow operation, to make it worse, building a Bitmap also needs some time, so we must implement some sort of optimization, I’m leaving the database part and focusing on the Bitmap creation.

Instead of recreating a new Bitmap each time we check to see if Read more…

Welcome to the third part of my tutorial on how to create a map app for Android without using Google™ APIs :).

Series outline:

• Series aim.
• Theory you need to know.
• App design.
• Writing a TilesManager.
• Writing a TilesProvider.
• Seeing results with MapView.
• Adding web support.
• Creating MapView in XML.
• Extra: Fuchs Maps.

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Okay, I’m supposed to show you a class diagram here but I changed my mind, since the app is simple I’ll explain each class in some lines :).

TilesManager: this class contains all the calculations needed to power our app, as I mentioned before maps are made up of tiles, we need to know exactly what tiles to fetch, we also need to convert latitude and longitude to pixel coordinates to display markers, this class by itself doesn’t contain the tiles, it just provides us with methods to Read more…

Welcome to the second part of my tutorial on how to create a map app for Android without using Google™ APIs :).

Series outline:

• Series aim.
• Theory you need to know.
• App design.
• Writing a TilesManager.
• Writing a TilesProvider.
• Seeing results with MapView.
• Adding web support.
• Creating MapView in XML.
• Extra: Fuchs Maps.

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In this part I’ll give simple information about maps and some terms and how they are used, hopefully saving you some time of searching.

Since I’m not a geography expert, please note that some information here might not be accurate, corrections are welcome 🙂 after all I’m just a programmer who learned what he needs to accomplish his goal.

I’ll provide additional links for further reading at the end of this post.

Earth shape : although the earth isn’t a perfect sphere, some map systems treat it as a sphere, I guess that’s okay for everyday use.

Map projection : from Wikipedia: “A map projection is any method of representing the surface of a sphere or other three-dimensional body on a plane. Map projections are necessary for creating maps. All map projections distort the surface in some fashion. Depending on the purpose of the map, some distortions are Read more…