feat: automatically import Android plugins

android/capacitor/src/main/java/com/getcapacitor/BridgeActivity.java

@@ -15,29 +15,46 @@ public class BridgeActivity extends AppCompatActivity {
     private JSONObject config;
     private int activityDepth = 0;
     private List<Class<? extends Plugin>> initialPlugins = new ArrayList<>();
-    protected Bridge.Builder bridgeBuilder = new Bridge.Builder();
+    private final Bridge.Builder bridgeBuilder = new Bridge.Builder();
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         bridgeBuilder.setInstanceState(savedInstanceState);
     }
 
+    /**
+     * @deprecated It is preferred not to call this method. If it is not called, the bridge is
+     * initialized automatically. If you need to add additional plugins during initialization,
+     * use {@link BridgeActivity#bridgeBuilder}.
+     */
+    @Deprecated
     protected void init(Bundle savedInstanceState, List<Class<? extends Plugin>> plugins) {
         this.init(savedInstanceState, plugins, null);
     }
 
+    /**
+     * @deprecated It is preferred not to call this method. If it is not called, the bridge is
+     * initialized automatically. If you need to add additional plugins during initialization,
+     * use {@link BridgeActivity#bridgeBuilder}.
+     */
+    @Deprecated
     protected void init(Bundle savedInstanceState, List<Class<? extends Plugin>> plugins, JSONObject config) {
         this.initialPlugins = plugins;
         this.config = config;
 
-        this.load(savedInstanceState);
+        this.load();
     }
 
     /**
-     * Load the WebView and create the Bridge
+     * @deprecated This method should not be called manually.
      */
+    @Deprecated
     protected void load(Bundle savedInstanceState) {
+        this.load();
+    }
+
+    private void load() {
         getApplication().setTheme(getResources().getIdentifier("AppTheme_NoActionBar", "style", getPackageName()));
         setTheme(getResources().getIdentifier("AppTheme_NoActionBar", "style", getPackageName()));
         setTheme(R.style.AppTheme_NoActionBar);
@@ -51,6 +68,14 @@ protected void load(Bundle savedInstanceState) {
         this.onNewIntent(getIntent());
     }
 
+    public void registerPlugin(Class<? extends Plugin> plugin) {
+        bridgeBuilder.addPlugin(plugin);
+    }
+
+    public void registerPlugins(List<Class<? extends Plugin>> plugins) {
+        bridgeBuilder.addPlugins(plugins);
+    }
+
     public Bridge getBridge() {
         return this.bridge;
     }
@@ -64,6 +89,20 @@ public void onSaveInstanceState(Bundle outState) {
     @Override
     public void onStart() {
         super.onStart();
+
+        // Preferred behavior: init() was not called, so we construct the bridge with auto-loaded plugins.
+        if (bridge == null) {
+            PluginManager loader = new PluginManager(getAssets());
+
+            try {
+                bridgeBuilder.addPlugins(loader.loadPluginClasses());
+            } catch (PluginLoadException ex) {
+                Logger.error("Error loading plugins.", ex);
+            }
+
+            this.load();
+        }
+
         activityDepth++;
         this.bridge.onStart();
         Logger.debug("App started");

android/capacitor/src/main/java/com/getcapacitor/PluginManager.java

@@ -0,0 +1,56 @@
+package com.getcapacitor;
+
+import android.content.res.AssetManager;
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
+import org.json.JSONArray;
+import org.json.JSONException;
+import org.json.JSONObject;
+
+public class PluginManager {
+
+    private final AssetManager assetManager;
+
+    public PluginManager(AssetManager assetManager) {
+        this.assetManager = assetManager;
+    }
+
+    public List<Class<? extends Plugin>> loadPluginClasses() throws PluginLoadException {
+        JSONArray pluginsJSON = parsePluginsJSON();
+        ArrayList<Class<? extends Plugin>> pluginList = new ArrayList<>();
+
+        try {
+            for (int i = 0, size = pluginsJSON.length(); i < size; i++) {
+                JSONObject pluginJSON = pluginsJSON.getJSONObject(i);
+                String classPath = pluginJSON.getString("classpath");
+                Class<?> c = Class.forName(classPath);
+                pluginList.add(c.asSubclass(Plugin.class));
+            }
+        } catch (JSONException e) {
+            throw new PluginLoadException("Could not parse capacitor.plugins.json as JSON");
+        } catch (ClassNotFoundException e) {
+            throw new PluginLoadException("Could not find class by class path: " + e.getMessage());
+        }
+
+        return pluginList;
+    }
+
+    private JSONArray parsePluginsJSON() throws PluginLoadException {
+        try (BufferedReader reader = new BufferedReader(new InputStreamReader(assetManager.open("capacitor.plugins.json")))) {
+            StringBuilder builder = new StringBuilder();
+            String line;
+            while ((line = reader.readLine()) != null) {
+                builder.append(line);
+            }
+            String jsonString = builder.toString();
+            return new JSONArray(jsonString);
+        } catch (IOException e) {
+            throw new PluginLoadException("Could not load capacitor.plugins.json");
+        } catch (JSONException e) {
+            throw new PluginLoadException("Could not parse capacitor.plugins.json as JSON");
+        }
+    }
+}

cli/src/android/update.ts

@@ -1,5 +1,14 @@
-import { copy, remove, pathExists, readFile, writeFile } from '@ionic/utils-fs';
-import { dirname, join, relative, resolve } from 'path';
+import {
+  copy,
+  remove,
+  pathExists,
+  readdirp,
+  readFile,
+  writeFile,
+  writeJSON,
+} from '@ionic/utils-fs';
+import Debug from 'debug';
+import { dirname, extname, join, relative, resolve } from 'path';
 
 import c from '../colors';
 import { checkPlatformVersions, runTask } from '../common';
@@ -27,6 +36,7 @@ import { resolveNode } from '../util/node';
 import { getAndroidPlugins } from './common';
 
 const platform = 'android';
+const debug = Debug('capacitor:android:update');
 
 export async function updateAndroid(config: Config): Promise<void> {
   const plugins = await getPluginsTask(config);
@@ -37,6 +47,7 @@ export async function updateAndroid(config: Config): Promise<void> {
 
   printPlugins(capacitorPlugins, 'android');
 
+  await writePluginsJson(config, capacitorPlugins);
   await removePluginsNativeFiles(config);
   const cordovaPlugins = plugins.filter(
     p => getPluginType(p, platform) === PluginType.Cordova,
@@ -61,6 +72,99 @@ function getGradlePackageName(id: string): string {
   return id.replace('@', '').replace('/', '-');
 }
 
+interface PluginsJsonEntry {
+  pkg: string;
+  classpath: string;
+}
+
+async function writePluginsJson(
+  config: Config,
+  plugins: Plugin[],
+): Promise<void> {
+  const classes = await findAndroidPluginClasses(plugins);
+  const pluginsJsonPath = resolve(
+    config.android.assetsDirAbs,
+    'capacitor.plugins.json',
+  );
+
+  await writeJSON(pluginsJsonPath, classes, { spaces: '\t' });
+}
+
+async function findAndroidPluginClasses(
+  plugins: Plugin[],
+): Promise<PluginsJsonEntry[]> {
+  const entries: PluginsJsonEntry[] = [];
+
+  for (const plugin of plugins) {
+    entries.push(...(await findAndroidPluginClassesInPlugin(plugin)));
+  }
+
+  return entries;
+}
+
+async function findAndroidPluginClassesInPlugin(
+  plugin: Plugin,
+): Promise<PluginsJsonEntry[]> {
+  if (!plugin.android || getPluginType(plugin, platform) !== PluginType.Core) {
+    return [];
+  }
+
+  const srcPath = resolve(plugin.rootPath, plugin.android.path, 'src/main');
+  const srcFiles = await readdirp(srcPath, {
+    filter: entry =>
+      !entry.stats.isDirectory() &&
+      ['.java', '.kt'].includes(extname(entry.path)),
+  });
+
+  const classRegex = /^@(?:CapacitorPlugin|NativePlugin)[\s\S]+?class ([\w]+)/gm;
+  const packageRegex = /^package ([\w.]+);?$/gm;
+
+  debug(
+    'Searching %O source files in %O by %O regex',
+    srcFiles.length,
+    srcPath,
+    classRegex,
+  );
+
+  const entries = await Promise.all(
+    srcFiles.map(
+      async (srcFile): Promise<PluginsJsonEntry | undefined> => {
+        const srcFileContents = await readFile(srcFile, { encoding: 'utf-8' });
+        const classMatch = classRegex.exec(srcFileContents);
+
+        if (classMatch) {
+          const className = classMatch[1];
+
+          debug('Searching %O for package by %O regex', srcFile, packageRegex);
+
+          const packageMatch = packageRegex.exec(
+            srcFileContents.substring(0, classMatch.index),
+          );
+
+          if (!packageMatch) {
+            logFatal(
+              `Package could not be parsed from Android plugin.\n` +
+                `Location: ${c.strong(srcFile)}`,
+            );
+          }
+
+          const packageName = packageMatch[1];
+          const classpath = `${packageName}.${className}`;
+
+          debug('%O is a suitable plugin class', classpath);
+
+          return {
+            pkg: plugin.id,
+            classpath,
+          };
+        }
+      },
+    ),
+  );
+
+  return entries.filter((entry): entry is PluginsJsonEntry => !!entry);
+}
+
 export async function installGradlePlugins(
   config: Config,
   capacitorPlugins: Plugin[],