Adding a Google+ Sign-in Screen

There's quite a lot of code (relatively speaking) to get this off the ground, so we'll use this step as more of a 'configuration' step, and hopefully once you've completed this, you'll be able to 'Go Green' on your own app :-) (Reduce,Reuse,Recycle my code).

The first thing you need to do is introduce the following variables into your Base class

/* Client used to interact with Google APIs. */
public static GoogleApiClient mGoogleApiClient;

public static boolean signedIn = false;
public static String googleToken;
public static String googleName;
public static String googleMail;
public static String googlePhotoURL;
public static Bitmap googlePhoto;
public static int drawerID = 0;

and the following method

public void logout(MenuItem item) 
    { 
    Log.v("coffeemate","Logging out from: " + mGoogleApiClient); 
    Base.signedIn = mGoogleApiClient.isConnected(); 
        if (Base.signedIn) 
        { 
        Log.v("coffeemate","Logging out from: " + mGoogleApiClient); 
        Plus.AccountApi.clearDefaultAccount(mGoogleApiClient); 
        mGoogleApiClient.disconnect(); 
        Base.googleToken = ""; 
        Base.signedIn = mGoogleApiClient.isConnected(); 
        mGoogleApiClient.connect(); 
        Log.v("coffeemate","googleClient Connected: " + Base.signedIn); 
        Toast.makeText(this, "Signing out of Google", Toast.LENGTH_LONG).show(); 
        Log.v("coffeemate", "CoffeeMate App Terminated"); 
        } 

    startActivity(new Intent(Base.this, Login.class) 
        .setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK));
    }

Then, bring in the following resources into your own CoffeeMate project (and store in the relevant folders) and fix/import any errors. You may need to revisit the Nav Drawer layout to rename some widgets.

• Login Activity (in package ie.cm.activities)
• activity_login Layout (in res\/layout)

Also, just confirm that you have the following permissions in your manifest file

<uses-permission android:name="android.permission.INTERNET" />

Next, bring in a 'Logout' Option in your Menu, like so

<item    
    android:id="@+id/menu_logout"    
    android:title="Logout"    
    android:orderInCategory="100"    
    app:showAsAction="never"    
    android:onClick="logout"/>

Now, introduce the following variable in your Home Activity

private ImageView googlePhoto;

and the following code in your onCreate() method BEFORE your fragment transaction

//SetUp GooglePhoto and Email for Drawer here
googlePhoto = (ImageView)navigationView.getHeaderView(0).findViewById(R.id.googlephoto);
CoffeeApi.getGooglePhoto(Base.googlePhotoURL,googlePhoto);

TextView googleName = (TextView)navigationView.getHeaderView(0).findViewById(R.id.googlename);
googleName.setText(Base.googleName);

TextView googleMail = (TextView)navigationView.getHeaderView(0).findViewById(R.id.googlemail);
googleMail.setText(Base.googleMail);

You'll get an error on

CoffeeApi.getGooglePhoto(Base.googlePhotoURL,googlePhoto);

so add the following method to your CoffeeApi class

public static void getGooglePhoto(String url,final ImageView googlePhoto) 
    { 
    ImageRequest imgRequest = new ImageRequest(url, 
        new Response.Listener<Bitmap>() { 
        @Override public void onResponse(Bitmap response) { 
                Base.googlePhoto = response;                         
                googlePhoto.setImageBitmap(Base.googlePhoto); 
            } }, 0, 0, ImageView.ScaleType.FIT_XY, Bitmap.Config.ARGB_8888, 

        new Response.ErrorListener() { 
            @Override public void onErrorResponse(VolleyError error) {             
                    System.out.println("Something went wrong!"); 
                    error.printStackTrace(); 
                } 
        });
    // Add the request to the queue 
    Base.app.add(imgRequest);

There's one other small step, but a vital one, to get your Login Screen loading after your splash Screen - and I'll leave that up to you.

Once you get the app running and a user Signing in - you'll see that the list can be downloaded as before, and the users Google credentials are dispalyed in the Nav Drawer - but nothing else works properly - the rest of the lab involves refactoring our code to make API requests on the Server to Delete/Update etc.