Android using SharedPreferences

Question

I found out a common way to store data is Android's SharedPreferences. So I went out and tried to implement it with my application.

What I want to do:

• My application retrieves weather details from the users current location, if the user desires he/she can add the location by pressing add to favorites. They can have up to 10 favorite locations. So I want to store the location description (exp: Dayton, OH), the latitude and longitude (So I may fetch the details when they want to see that weather). So Shared Preferences seem to fit my need.

What I did: - I created a loop that would cycle through 10 keys (for 10 locations) an as long as the keys were null the location information would be saved. If the key was not null, it means the key has already been created.

My code:

public void writeNewLocation(String stringLat, String stringLon, String location) {

    this.latitude = stringLat;
    this.longitude = stringLon;
    this.location = location;

    pref = mContext.getSharedPreferences("favoritelocations", 0); // 0 - for private mode
    Editor editor = pref.edit();

    //Loop through all the favorite keys to find an open spot:
    for(int i = 1; i <= 10; i++) {

        //Test for current favorite key:
        String value = pref.getString("favorite"+ i +"_location",null);

        if (value == null) {
            //The key does not exist so it can be created and written to:
            //First write the location description:
            editor.putString("favorite" + i + "_location", location);
            //Next the write the latitude and lonitude values:
            editor.putString("favorite" + i + "_latitude", latitude);
            editor.putString("favorite" + i + "_longitude", longitude);
            editor.commit();
            i = 11;
        } else {
            //If at end of loop; Inform user:
            if(i == 10) {
                //Display an error:
                //Instantiate an AlertDialog.Builder with its constructor
                AlertDialog.Builder builder = new AlertDialog.Builder(mContext);

                //Create the AlertDialog characteristics:
                builder.setMessage("You can only have up to 10 favorite locations. Delete some to make room.");
                builder.setTitle("Message");

                //Show the AlertDialog:
                msgDialog = builder.create();
                editor.commit();
                i = 11;
            } else {
                //Back to top of loop.
            }
        }
    }

    //Commit to changes:
    editor.commit(); // commit changes
}

So I loop through ten possible keys, if it hits 10, and all spots are taken, I alert the user. But when I call this method to create a favorite location, then call 1 of the 10 getters to display the information that should've been saved, I get a null. :( Is it too early in the morning over here or am I doing something wrong...

Thanks c: