Merge pull request microsoft#491 from igrayson/patch-1

[Android] Support React instances with no Activity

Author: geof90

.gitignore

@@ -132,6 +132,7 @@ gen/
 .gradle/
 build/
 */build/
+android/app/gradle*
 
 # Local configuration file (sdk path, etc)
 local.properties
@@ -149,4 +150,4 @@ proguard/
 captures/
 
 # Remove after this framework is published on NPM
-code-push-plugin-testing-framework/node_modules
+code-push-plugin-testing-framework/node_modules

README.md

@@ -343,6 +343,57 @@ public class MainActivity extends ReactActivity {
 }
 ```
 
+#### Background React Instances ####
+
+**This section is only necessary if you're *explicitly* launching a React Native instance without an `Activity` (for example, from within a native push notification receiver). For these situations, CodePush must be told how to find your React Native instance.**
+
+In order to update/restart your React Native instance, CodePush must be configured with a `ReactInstanceHolder` before attempting to restart an instance in the background. This is usually done in your `Application` implementation.
+
+**For React Native >= v0.29**
+
+Update the `MainApplication.java` file to use CodePush via the following changes:
+
+```java
+...
+// 1. Declare your ReactNativeHost to extend ReactInstanceHolder. ReactInstanceHolder is a subset of ReactNativeHost, so no additional implementation is needed.
+import com.microsoft.codepush.react.ReactInstanceHolder;
+
+public class MyReactNativeHost extends ReactNativeHost implements ReactInstanceHolder {
+  // ... usual overrides
+}
+
+// 2. Provide your ReactNativeHost to CodePush.
+
+public class MainApplication extends Application implements ReactApplication {
+
+   private final MyReactNativeHost mReactNativeHost = new MyReactNativeHost(this);
+   
+   @Override
+   public void onCreate() {
+     CodePush.setReactInstanceHolder(mReactNativeHost);
+     super.onCreate();
+  }
+}
+```
+
+**For React Native v0.19 - v0.28**
+
+Before v0.29, React Native did not provide a `ReactNativeHost` abstraction. If you're launching a background instance, you'll likely have built your own, which should now implement `ReactInstanceHolder`. Once that's done...
+
+```java
+// 1. Provide your ReactInstanceHolder to CodePush.
+
+public class MainApplication extends Application {
+   
+   @Override
+   public void onCreate() {
+     // ... initialize your instance holder
+     CodePush.setReactInstanceHolder(myInstanceHolder);
+     super.onCreate();
+  }
+}
+```
+
 In order to effectively make use of the `Staging` and `Production` deployments that were created along with your CodePush app, refer to the [multi-deployment testing](#multi-deployment-testing) docs below before actually moving your app's usage of CodePush into production.
 
 ## Windows Setup

android/app/src/main/java/com/microsoft/codepush/react/CodePush.java

@@ -1,5 +1,6 @@
 package com.microsoft.codepush.react;
 
+import com.facebook.react.ReactInstanceManager;
 import com.facebook.react.ReactPackage;
 import com.facebook.react.bridge.JavaScriptModule;
 import com.facebook.react.bridge.NativeModule;
@@ -44,6 +45,7 @@ public class CodePush implements ReactPackage {
     private Context mContext;
     private final boolean mIsDebugMode;
 
+    private static ReactInstanceHolder mReactInstanceHolder;
     private static CodePush mCurrentInstance;
 
     public CodePush(String deploymentKey, Context context) {
@@ -277,6 +279,17 @@ public void clearUpdates() {
         mSettingsManager.removeFailedUpdates();
     }
 
+    public static void setReactInstanceHolder(ReactInstanceHolder reactInstanceHolder) {
+        mReactInstanceHolder = reactInstanceHolder;
+    }
+
+    static ReactInstanceManager getReactInstanceManager() {
+        if (mReactInstanceHolder == null) {
+            return null;
+        }
+        return mReactInstanceHolder.getReactInstanceManager();
+    }
+    
     @Override
     public List<NativeModule> createNativeModules(ReactApplicationContext reactApplicationContext) {
         CodePushNativeModule codePushModule = new CodePushNativeModule(reactApplicationContext, this, mUpdateManager, mTelemetryManager, mSettingsManager);
@@ -297,4 +310,4 @@ public List<Class<? extends JavaScriptModule>> createJSModules() {
     public List<ViewManager> createViewManagers(ReactApplicationContext reactApplicationContext) {
         return new ArrayList<>();
     }
-}
+}

android/app/src/main/java/com/microsoft/codepush/react/CodePushNativeModule.java

@@ -1,8 +1,9 @@
 package com.microsoft.codepush.react;
 
 import android.app.Activity;
-import android.content.Context;
 import android.os.AsyncTask;
+import android.os.Handler;
+import android.os.Looper;
 import android.provider.Settings;
 import android.view.Choreographer;
 
@@ -36,7 +37,7 @@ public class CodePushNativeModule extends ReactContextBaseJavaModule {
     private String mClientUniqueId = null;    
     private LifecycleEventListener mLifecycleEventListener = null;
     private int mMinimumBackgroundDuration = 0;
-    
+
     private CodePush mCodePush;
     private SettingsManager mSettingsManager;
     private CodePushTelemetryManager mTelemetryManager;
@@ -78,16 +79,13 @@ public String getName() {
         return "CodePush";
     }
 
-    private boolean isReactApplication(Context context) {
-        Class<?> reactApplicationClass = tryGetClass(REACT_APPLICATION_CLASS_NAME);
-        if (reactApplicationClass != null && reactApplicationClass.isInstance(context)) {
-            return true;
+    private void loadBundleLegacy() {
+        final Activity currentActivity = getCurrentActivity();
+        if (currentActivity == null) {
+            // The currentActivity can be null if it is backgrounded / destroyed, so we simply
+            // no-op to prevent any null pointer exceptions.
+            return;
         }
-
-        return false;
-    }
-
-    private void loadBundleLegacy(final Activity currentActivity) {
         mCodePush.invalidateCurrentInstance();
 
         currentActivity.runOnUiThread(new Runnable() {
@@ -100,41 +98,14 @@ public void run() {
 
     private void loadBundle() {
         mCodePush.clearDebugCacheIfNeeded();
-        final Activity currentActivity = getCurrentActivity();
-
-        if (currentActivity == null) {
-            // The currentActivity can be null if it is backgrounded / destroyed, so we simply
-            // no-op to prevent any null pointer exceptions.
-            return;
-        }
-
         try {
-            ReactInstanceManager instanceManager;
             // #1) Get the ReactInstanceManager instance, which is what includes the
             //     logic to reload the current React context.
-            try {
-                // In RN >=0.29, the "mReactInstanceManager" field yields a null value, so we try
-                // to get the instance manager via the ReactNativeHost, which only exists in 0.29.
-                Method getApplicationMethod = ReactActivity.class.getMethod("getApplication");
-                Object reactApplication = getApplicationMethod.invoke(currentActivity);
-                Class<?> reactApplicationClass = tryGetClass(REACT_APPLICATION_CLASS_NAME);
-                Method getReactNativeHostMethod = reactApplicationClass.getMethod("getReactNativeHost");
-                Object reactNativeHost = getReactNativeHostMethod.invoke(reactApplication);
-                Class<?> reactNativeHostClass = tryGetClass(REACT_NATIVE_HOST_CLASS_NAME);
-                Method getReactInstanceManagerMethod = reactNativeHostClass.getMethod("getReactInstanceManager");
-                instanceManager = (ReactInstanceManager)getReactInstanceManagerMethod.invoke(reactNativeHost);
-            } catch (Exception e) {
-                // The React Native version might be older than 0.29, or the activity does not
-                // extend ReactActivity, so we try to get the instance manager via the
-                // "mReactInstanceManager" field.
-                Class instanceManagerHolderClass = currentActivity instanceof ReactActivity
-                        ? ReactActivity.class
-                        : currentActivity.getClass();
-                Field instanceManagerField = instanceManagerHolderClass.getDeclaredField("mReactInstanceManager");
-                instanceManagerField.setAccessible(true);
-                instanceManager = (ReactInstanceManager)instanceManagerField.get(currentActivity);
+            final ReactInstanceManager instanceManager = resolveInstanceManager();
+            if (instanceManager == null) {
+                return;
             }
-
+            
             String latestJSBundleFile = mCodePush.getJSBundleFileInternal(mCodePush.getAssetsBundleFileName());
 
             // #2) Update the locally stored JS bundle file path
@@ -155,27 +126,60 @@ private void loadBundle() {
 
             // #3) Get the context creation method and fire it on the UI thread (which RN enforces)
             final Method recreateMethod = instanceManager.getClass().getMethod("recreateReactContextInBackground");
-
-            final ReactInstanceManager finalizedInstanceManager = instanceManager;
-            currentActivity.runOnUiThread(new Runnable() {
+            new Handler(Looper.getMainLooper()).post(new Runnable() {
                 @Override
                 public void run() {
                     try {
-                        recreateMethod.invoke(finalizedInstanceManager);
+                        recreateMethod.invoke(instanceManager);
                         mCodePush.initializeUpdateAfterRestart();
-                    }
-                    catch (Exception e) {
+                    } catch (Exception e) {
                         // The recreation method threw an unknown exception
-                        // so just simply fallback to restarting the Activity
-                        loadBundleLegacy(currentActivity);
+                        // so just simply fallback to restarting the Activity (if it exists)
+                        loadBundleLegacy();
                     }
                 }
             });
+
         } catch (Exception e) {
             // Our reflection logic failed somewhere
-            // so fall back to restarting the Activity
-            loadBundleLegacy(currentActivity);
+            // so fall back to restarting the Activity (if it exists)
+            loadBundleLegacy();
+        }
+    }
+    
+    private ReactInstanceManager resolveInstanceManager() throws NoSuchFieldException, IllegalAccessException {
+        ReactInstanceManager instanceManager = CodePush.getReactInstanceManager();
+        if (instanceManager != null) {
+            return instanceManager;
+        }
+
+        final Activity currentActivity = getCurrentActivity();
+        if (currentActivity == null) {
+            return null;
+        }
+        try {
+            // In RN >=0.29, the "mReactInstanceManager" field yields a null value, so we try
+            // to get the instance manager via the ReactNativeHost, which only exists in 0.29.
+            Method getApplicationMethod = ReactActivity.class.getMethod("getApplication");
+            Object reactApplication = getApplicationMethod.invoke(currentActivity);
+            Class<?> reactApplicationClass = tryGetClass(REACT_APPLICATION_CLASS_NAME);
+            Method getReactNativeHostMethod = reactApplicationClass.getMethod("getReactNativeHost");
+            Object reactNativeHost = getReactNativeHostMethod.invoke(reactApplication);
+            Class<?> reactNativeHostClass = tryGetClass(REACT_NATIVE_HOST_CLASS_NAME);
+            Method getReactInstanceManagerMethod = reactNativeHostClass.getMethod("getReactInstanceManager");
+            instanceManager = (ReactInstanceManager)getReactInstanceManagerMethod.invoke(reactNativeHost);
+        } catch (Exception e) {
+            // The React Native version might be older than 0.29, or the activity does not
+            // extend ReactActivity, so we try to get the instance manager via the
+            // "mReactInstanceManager" field.
+            Class instanceManagerHolderClass = currentActivity instanceof ReactActivity
+                    ? ReactActivity.class
+                    : currentActivity.getClass();
+            Field instanceManagerField = instanceManagerHolderClass.getDeclaredField("mReactInstanceManager");
+            instanceManagerField.setAccessible(true);
+            instanceManager = (ReactInstanceManager)instanceManagerField.get(currentActivity);
         }
+        return instanceManager;
     }
 
     private Class tryGetClass(String className) {
@@ -505,4 +509,4 @@ public void downloadAndReplaceCurrentBundle(String remoteBundleUrl) {
             }
         }
     }
-}
+}

android/app/src/main/java/com/microsoft/codepush/react/ReactInstanceHolder.java

@@ -0,0 +1,17 @@
+package com.microsoft.codepush.react;
+
+import com.facebook.react.ReactInstanceManager;
+
+/**
+ * Provides access to a {@link ReactInstanceManager}.
+ *
+ * ReactNativeHost already implements this interface, if you make use of that react-native
+ * component (just add `implements ReactInstanceHolder`).
+ */
+public interface ReactInstanceHolder {
+
+  /**
+   * Get the current {@link ReactInstanceManager} instance. May return null.
+   */
+  ReactInstanceManager getReactInstanceManager();
+}