android Config to "sample first"

Change-Id: Ic01e5016f91d2c92336486c4df0162054d3eba08

Author: kroikie

config/README.md

@@ -1,20 +1,78 @@
 Firebase Remote Config Quickstart
 ==============================
 
+The Firebase Remote Config Android quickstart app demonstrates using Remote
+Config to define user-facing text in an Android app.
+
 Introduction
 ------------
 
-- [Read more about Firebase Remote Config](https://firebase.google.com/docs/remote-config/)
+This is a simple example of using Remote Config to override in-app default
+values by defining service-side parameter values in the Firebase console. This
+example demonstrates a small subset of the capilities of Firebase Remote
+Config. To learn more about how you can use Firebase Remote Config in your app,
+see
+[Firebase Remote Config Introduction](https://firebase.google.com/docs/remote-config/).
 
-Getting Started
+Getting started
 ---------------
 
-- [Add Firebase to your Android Project](https://firebase.google.com/docs/android/setup).
-- Run the sample on Android device or emulator.
+1. [Add Firebase to your Android Project](https://firebase.google.com/docs/android/setup).
+2. [Create a Remote Config project for the quickstart sample](https://firebase.google.com/docs/remote-config/android#create_a_product_name_project_for_the_quickstart_sample),
+  defining the parameter values and parameter keys used by the sample.
+3. Run the sample on an Android device or emulator.
+4. Change one or more parameter values in the Firebase Console (the value of
+  `welcome_message`, `welcome_message_caps`, or both).
+5. Tap **Fetch Remote Config** in the app to fetch new parameter values and see
+  the resulting change in the app.
+
+Best practices
+--------------
+This section provides some additional information about how the quickstart
+example sets in-app default parameter values and fetches values from the Remote
+Config service
+
+### In-app default parameter values ###
+
+In-app default values are set using an XML file in this example, but you can
+also set in-app default values inline using other `setDefault` methods of the
+[`FirebaseRemoteConfig` class](https://firebase.google.com/docs/reference/android/com/google/firebase/remoteconfig/FirebaseRemoteConfig#public-method-summary).
+Then, you can override only those values that you need to change from the
+Firebase console. This lets you use Remote Config for any default value that you
+might want to override in the future, without the need to set all of those
+values in the Firebase console.
+
+### Fetch values from the Remote Config service ###
+
+When an app calls `fetch`, cached parameter values are used unless the last
+successful fetch occurred 12 hours ago, or unless a value less than 43200 (the
+number of seconds in 12 hours) is specified for `cacheExpirationSeconds`. If a
+cached value is not used, updated parameter values are fetched from the Remote
+Config service.
+
+Fetched values are cached locally, but not immediately activated. To activate
+fetched values so that they take effect, call the `activateFetched` method. In
+the quickstart sample app, you call this method from the UI by tapping
+**Fetch Remote Config**.
+
+You can also create a Remote Config Setting to enable developer mode, but you
+must remove this setting before distributing your app. Fetching Remote Config
+data from the service is normally limited to a few requests per hour. By
+enabling developer mode, you can make many more requests per hour, so you can
+test your app with different Remote Config parameter values during development.
+
+- To learn more about fetching data from remote config, see the Remote Config
+  Frequently Asked Question (FAQ) on
+  [fetching and activating parameter values](https://firebase.google.com/support/faq#remote-config-values).
+- To learn about parameters and conditions that you can use to change the
+  behavior and appearance of your app for segments of your userbase, see
+  [Remote Config Parameters and Conditions](https://firebase.google.com/docs/remote-config/parameters).
+- To learn more about the Remote Config API, see
+  [Remote Config API Overview](https://firebase.google.com/docs/remote-config/api-overview).
 
 Result
 -----------
-<img src="app/src/screen.png" height="534" width="300"/>
+<img src="https://github.com/firebase/quickstart-android/raw/master/config/app/src/screen.png" height="534" width="300"/>
 
 Support
 -------

config/app/src/main/java/com/google/samples/quickstart/config/MainActivity.java

@@ -66,23 +66,20 @@ public void onClick(View v) {
         mFirebaseRemoteConfig = FirebaseRemoteConfig.getInstance();
         // [END get_remote_config_instance]
 
-        // Create Remote Config Setting to enable developer mode.
-        // Fetching configs from the server is normally limited to 5 requests per hour.
-        // Enabling developer mode allows many more requests to be made per hour, so developers
-        // can test different config values during development.
+        // Create a Remote Config Setting to enable developer mode, which you can use to increase
+        // the number of fetches available per hour during development. See Best Practices in the
+        // README for more information.
         // [START enable_dev_mode]
         FirebaseRemoteConfigSettings configSettings = new FirebaseRemoteConfigSettings.Builder()
                 .setDeveloperModeEnabled(BuildConfig.DEBUG)
                 .build();
         mFirebaseRemoteConfig.setConfigSettings(configSettings);
         // [END enable_dev_mode]
 
-        // Set default Remote Config values. In general you should have in app defaults for all
-        // values that you may configure using Remote Config later on. The idea is that you
-        // use the in app defaults and when you need to adjust those defaults, you set an updated
-        // value in the App Manager console. Then the next time you application fetches from the
-        // server, the updated value will be used. You can set defaults via an xml file like done
-        // here or you can set defaults inline by using one of the other setDefaults methods.S
+        // Set default Remote Config parameter values. An app uses the in-app default values, and
+        // when you need to adjust those defaults, you set an updated value for only the values you
+        // want to change in the Firebase console. See Best Practices in the README for more
+        // information.
         // [START set_default_values]
         mFirebaseRemoteConfig.setDefaults(R.xml.remote_config_defaults);
         // [END set_default_values]
@@ -91,23 +88,23 @@ public void onClick(View v) {
     }
 
     /**
-     * Fetch welcome message from server.
+     * Fetch a welcome message from the Remote Config service, and then activate it.
      */
     private void fetchWelcome() {
         mWelcomeTextView.setText(mFirebaseRemoteConfig.getString(LOADING_PHRASE_CONFIG_KEY));
 
         long cacheExpiration = 3600; // 1 hour in seconds.
-        // If in developer mode cacheExpiration is set to 0 so each fetch will retrieve values from
-        // the server.
+        // If your app is using developer mode, cacheExpiration is set to 0, so each fetch will
+        // retrieve values from the service.
         if (mFirebaseRemoteConfig.getInfo().getConfigSettings().isDeveloperModeEnabled()) {
             cacheExpiration = 0;
         }
 
         // [START fetch_config_with_callback]
-        // cacheExpirationSeconds is set to cacheExpiration here, indicating that any previously
-        // fetched and cached config would be considered expired because it would have been fetched
-        // more than cacheExpiration seconds ago. Thus the next fetch would go to the server unless
-        // throttling is in progress. The default expiration duration is 43200 (12 hours).
+        // cacheExpirationSeconds is set to cacheExpiration here, indicating the next fetch request
+        // will use fetch data from the Remote Config service, rather than cached parameter values,
+        // if cached parameter values are more than cacheExpiration seconds old.
+        // See Best Practices in the README for more information.
         mFirebaseRemoteConfig.fetch(cacheExpiration)
                 .addOnCompleteListener(this, new OnCompleteListener<Void>() {
                     @Override
@@ -116,7 +113,7 @@ public void onComplete(@NonNull Task<Void> task) {
                             Toast.makeText(MainActivity.this, "Fetch Succeeded",
                                     Toast.LENGTH_SHORT).show();
 
-                            // Once the config is successfully fetched it must be activated before newly fetched
+                            // After config data is successfully fetched, it must be activated before newly fetched
                             // values are returned.
                             mFirebaseRemoteConfig.activateFetched();
                         } else {
@@ -130,8 +127,8 @@ public void onComplete(@NonNull Task<Void> task) {
     }
 
     /**
-     * Display welcome message in all caps if welcome_message_caps is set to true. Otherwise
-     * display welcome message as fetched from welcome_message.
+     * Display a welcome message in all caps if welcome_message_caps is set to true. Otherwise,
+     * display a welcome message as fetched from welcome_message.
      */
      // [START display_welcome_message]
     private void displayWelcomeMessage() {