Question

In my app, I have to find whether a given location comes under a specified area. I am taking Connaught Place, New Delhi as center point. and I got the addresses which come under area of 200 miles from center point. But, if I enter any invalid location, like “abcdfdfkc”, the app crashes, because it is trying to find coordinates of this location and I want to avoid this.

Below I am posting the code:

public static  boolean isServicedLocation(Context _ctx, String strAddress){
    boolean isServicedLocation = false;

    Address sourceAddress = getAddress(_ctx, "Connaught Place, New Delhi, India");
    Location sourceLocation = new Location("");
    sourceLocation.setLatitude(sourceAddress.getLatitude());
    sourceLocation.setLongitude(sourceAddress.getLongitude());      

    Address targetAddress = getAddress(_ctx, strAddress);
    Location targetLocation = new Location("");

    if (targetLocation != null) {
        targetLocation.setLatitude(targetAddress.getLatitude());
        targetLocation.setLongitude(targetAddress.getLongitude());
        float distance = Math.abs(sourceLocation.distanceTo(targetLocation));
        double distanceMiles = distance/1609.34;
        isServicedLocation = distanceMiles <= 200;

        //Toast.makeText(_ctx, "Distance "+distanceMiles, Toast.LENGTH_LONG).show();
    }       

    return isServicedLocation;
}

getAddress method:

public static Address getAddress(Context _ctx, String addressStr) {
    Geocoder geoCoder = new Geocoder(_ctx, Locale.getDefault());
    try {
        List<Address> addresses = geoCoder.getFromLocationName(addressStr,
                1);

        if (addresses.size() != 0) {
            return addresses.get(0);
        }
    } catch (Exception ex) {
        ex.printStackTrace();
    }

    return null;
}

Answer 1

It’s because when you don’t find an address from the GeoCoder (ie, if addresses.size() == 0), you return null.

Then, regardless of that, you dereference the value, which is what’s crashing your app.

Address targetAddress = getAddress(_ctx, strAddress);
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
:
if (targetLocation != null) {
    targetLocation.setLatitude(targetAddress.getLatitude());
                               ^^^^^^^^^^^^^

You should probably also be checking targetAddress for null to avoid this (either in addition to (likely), or instead of (less likely), the check of targetLocation).

So I’d be looking at changing:

if (targetLocation != null) {

into:

if ((targetLocation != null) && (targetAddress != null)) {

That way, an invalid address automatically becomes an unserviced location.