engine/shell/platform/android/io/flutter/view/FlutterMain.java

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package io.flutter.view;

import android.content.Context;
import android.os.Handler;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.annotation.VisibleForTesting;

import io.flutter.embedding.engine.loader.FlutterLoader;

/**
 * A class to intialize the Flutter engine.
 */
public class FlutterMain {

    public static class Settings {
        private String logTag;

        @Nullable
        public String getLogTag() {
            return logTag;
        }

        /**
         * Set the tag associated with Flutter app log messages.
         * @param tag Log tag.
         */
        public void setLogTag(String tag) {
            logTag = tag;
        }
    }

    /**
     * Starts initialization of the native system.
     * @param applicationContext The Android application context.
     */
    public static void startInitialization(@NonNull Context applicationContext) {
        if (isRunningInRobolectricTest) {
            return;
        }
        FlutterLoader.getInstance().startInitialization(applicationContext);
    }

    /**
     * Starts initialization of the native system.
     * <p>
     * This loads the Flutter engine's native library to enable subsequent JNI calls. This also
     * starts locating and unpacking Dart resources packaged in the app's APK.
     * <p>
     * Calling this method multiple times has no effect.
     *
     * @param applicationContext The Android application context.
     * @param settings Configuration settings.
     */
    public static void startInitialization(@NonNull Context applicationContext, @NonNull Settings settings) {
        if (isRunningInRobolectricTest) {
            return;
        }
        FlutterLoader.Settings newSettings = new FlutterLoader.Settings();
        newSettings.setLogTag(settings.getLogTag());
        FlutterLoader.getInstance().startInitialization(applicationContext, newSettings);
    }

    /**
     * Blocks until initialization of the native system has completed.
     * <p>
     * Calling this method multiple times has no effect.
     *
     * @param applicationContext The Android application context.
     * @param args Flags sent to the Flutter runtime.
     */
    public static void ensureInitializationComplete(@NonNull Context applicationContext, @Nullable String[] args) {
        if (isRunningInRobolectricTest) {
            return;
        }
        FlutterLoader.getInstance().ensureInitializationComplete(applicationContext, args);
    }

    /**
     * Same as {@link #ensureInitializationComplete(Context, String[])} but waiting on a background
     * thread, then invoking {@code callback} on the {@code callbackHandler}.
     */
    public static void ensureInitializationCompleteAsync(
        @NonNull Context applicationContext,
        @Nullable String[] args,
        @NonNull Handler callbackHandler,
        @NonNull Runnable callback
    ) {
        if (isRunningInRobolectricTest) {
            return;
        }
        FlutterLoader.getInstance().ensureInitializationCompleteAsync(
            applicationContext, args, callbackHandler, callback);
    }

    @NonNull
    public static String findAppBundlePath() {
        return FlutterLoader.getInstance().findAppBundlePath();
    }

    @Deprecated
    @Nullable
    public static String findAppBundlePath(@NonNull Context applicationContext) {
        return FlutterLoader.getInstance().findAppBundlePath();
    }

    /**
     * Returns the file name for the given asset.
     * The returned file name can be used to access the asset in the APK
     * through the {@link android.content.res.AssetManager} API.
     *
     * @param asset the name of the asset. The name can be hierarchical
     * @return      the filename to be used with {@link android.content.res.AssetManager}
     */
    @NonNull
    public static String getLookupKeyForAsset(@NonNull String asset) {
        return FlutterLoader.getInstance().getLookupKeyForAsset(asset);
    }

    /**
     * Returns the file name for the given asset which originates from the
     * specified packageName. The returned file name can be used to access
     * the asset in the APK through the {@link android.content.res.AssetManager} API.
     *
     * @param asset       the name of the asset. The name can be hierarchical
     * @param packageName the name of the package from which the asset originates
     * @return            the file name to be used with {@link android.content.res.AssetManager}
     */
    @NonNull
    public static String getLookupKeyForAsset(@NonNull String asset, @NonNull String packageName) {
        return FlutterLoader.getInstance().getLookupKeyForAsset(asset, packageName);
    }

    private static boolean isRunningInRobolectricTest = false;

    /*
     * Indicates whether we are currently running in a Robolectric Test.
     *
     * <p> Flutter cannot be initialized inside a Robolectric environment since it cannot load
     * native libraries.
     *
     * @deprecated Use the new embedding (io.flutter.embedding) instead which provides better
     *     modularity for testing.
     */
    @Deprecated
    @VisibleForTesting
    public static void setIsRunningInRobolectricTest(boolean isRunningInRobolectricTest) {
        FlutterMain.isRunningInRobolectricTest = isRunningInRobolectricTest;
    }
}