How can I trigger the Several Functionality of Google Maps in my App

Question

I am trying to create a maps app for a certain city that have some stored latitude and longitude for certain landmarks in the city. In the map,

• you can only zoom in and zoom out within the boundaries of the city
• While the app is open, when you reach a certain range of lat and long coordinates within a certain radius around the landmark, it will trigger and activity that will display details about the landmark and also a voice recording about the landmark
• also, the map must also have the "directions" functionality in it, where it can show several possible ways for you to get to a certain location (like landmark) from your present location and also display the distance between two points

I've already tried a GPS program from androidhive that detects your lat and long coordinates. I'm also trying to understand how to acquire and use the google maps api. I would like to know the possible approaches in doing it since I'm still new to android.

Thanks in Advance!

Answer 1

you can zoom with specific mile or kmeter by this code:this is for two mile:

    Display display = getWindowManager().getDefaultDisplay();

    // double equatorLength = 3218; // in meters
    double equatorLength = 40075004; // in meters
    double widthInPixels = display.getWidth();
    double metersPerPixel = equatorLength / 256;
    int zoomLevel = 1;
    // 2 mile=3218 mtr
    while ((metersPerPixel * widthInPixels) > 3218) {
        metersPerPixel /= 2;
        ++zoomLevel;
    }

    return zoomLevel;

hope this is helpfull for "you can only zoom in and zoom out within the boundaries of the city"