Creating a custom adapter

// Creating a custom adapter

// Right now the xml would look pretty good on most devices.
// But we can't test it until we create a custom adapter that allows us to attach
// our data to each item.

// Now, instead of using a simple collection of strings,
// we can use a collection of objects and adapt them for the new layout.
// We do this by extending one of the base adapter classes from the Android SDK.
// Extending an existing adaptor allows us to tap into certain functionality
// that we don't want to build from the ground up.
// Our new custom adapter will focus on how to fill the layout with
// the appropriate data.
// We're basically mapping from our model to our view.

Pic:
http://content.screencast.com/users/yofu1234/folders/Jing/media/aababbf1-d235-4a87-894e-c0f8270ebc55/Now,%20we%20will%20create%20the%20adapter%20that%20maps%20each%20piece%20of%20data%20from%20the%20Day%20class.png
// Now, we will create the adapter that maps each piece of data from the Day class to a field in the layout.

// Our adapter will be a customized version of the array adapter we are already using.
// And how do we customize existing classes in Java?
// We subclass them.

//Let's start by creating a new package to hold our adapters.
// Right-click on our main stormy package and select New > Package and type in adapters.
// So let's start with a new file.
// Right-click > New > Java Class.
// And let's call this the DayAdapter and click Enter.
// And the very first thing we want to do is extend one of the base adapters.
// then Alt+Enter to implement methods and @Override.

package com.teamtreehouse.stormy.adapters;

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;

import com.teamtreehouse.stormy.weather.Day;

/**
 * Created by Fu on 7/16/2015.
 */
public class DayAdapter extends BaseAdapter {

    //Step 1. This adapter needs to know the context and the data its going to map:
    private Context mContext; //lets create Context and call it mContext
    private Day[] mDays;  //and lets create a private Day array and call it mDays

    //Step 2. Now lets create a constructor that allows us to set these two values.
    public DayAdapter(Context context, Day[] days){
        mContext = context;
        mDays = days;
    }

    //Step 3. Next, move through these methods and implement them one by one

    @Override
    //getCount, gets us the count of items in the array that this adapter is using. So that is just the count of the mDays array.
    public int getCount() {
        return mDays.length; //so we can use the property: mDays.length
    }

    @Override
    //getItem gets the item for the adapter given a certain position.
    public Object getItem(int position) {
        return mDays[position]; // So we'll do mDays and the item at position. <- get data from the mDays array again like in the previous method.
    }

    @Override
    //we aren't going to use ItemId. This method is used to Tag items for easy reference.
    public long getItemId(int position) {
        return 0;
    }

    @Override
    //getView is where the mapping occurs.
    public View getView(int position, View convertView, ViewGroup parent) {
        return null;
    }
}