EhViewer/app/src/main/java/com/hippo/scene/Scene.java

/*
 * Copyright (C) 2014-2015 Hippo Seven
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.hippo.scene;

import android.content.Intent;
import android.os.Bundle;
import android.os.Parcelable;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.FragmentManager;
import android.util.SparseArray;
import android.view.View;
import android.view.ViewParent;

import com.hippo.util.AssertUtils;

/**
 * {@link com.hippo.scene.Scene} is a {@code Activity} of {@link android.app.Activity}.
 * <p>
 * When start a new {@code Scene}, previous {@code Scene} can stay at screen for
 * a while. Or retain for a while before destroy.
 */
public abstract class Scene {

    private @Nullable View mSceneView;

    private static SceneManager sSceneManager;

    static void setSceneManager(SceneManager sceneManager) {
        sSceneManager = sceneManager;
    }

    // If there is no StageActivity for SceneManager, yout will get AssertError
    public @NonNull StageActivity getStageActivity() {
        StageActivity stageActivity = sSceneManager.getStageActivity();
        AssertUtils.assertNotNull("StageActivity is null", stageActivity);
        return stageActivity;
    }

    @Nullable View getSceneView() {
        return mSceneView;
    }

    public void startScene(@NonNull Class sceneClass) {
        sSceneManager.startScene(sceneClass, null, null);
    }

    public void startScene(@NonNull Class sceneClass, @Nullable Announcer announcer) {
        sSceneManager.startScene(sceneClass, announcer, null);
    }

    public void startScene(@NonNull Class sceneClass, @Nullable Announcer announcer,
            @Nullable Curtain curtain) {
        sSceneManager.startScene(sceneClass, announcer, curtain);
    }

    public final void finish() {
        sSceneManager.finishScene(this);
    }

    void create(Bundle savedInstanceState) {
        onCreate(savedInstanceState);
        mSceneView = onCreateSceneView(savedInstanceState);

        // Make sure scene view is attach from stage
        attachToStage();
    }

    void resume() {
        onResume();
    }

    void pause() {
        onPause();
    }

    void destroy(boolean removeScene) {
        onDestroy();

        if (removeScene) {
            // Make sure scene view is detached from stage
            detachFromeStage();
        }
    }

    /**
     * It is called when scene is created
     *
     * @param savedInstanceState null for first time, non null for recrearte
     */
    protected void onCreate(Bundle savedInstanceState) {
    }

    /**
     * It is called after {@link #onCreate(android.os.Bundle)}.
     * Create view of the scene.
     *
     * @param savedInstanceState null for first time, non null for recrearte
     * @return the view of the scene
     */
    protected @Nullable View onCreateSceneView(Bundle savedInstanceState) {
        return null;
    }

    protected void onResume() {
    }

    protected void onPause() {
    }

    protected void onDestroy() {
    }


    /**
     * Is scene view attached to stage
     *
     * @return if scene view is null, always return false;
     */
    public boolean isInStage() {
        if (mSceneView == null) {
            return false;
        } else {
            ViewParent parent = mSceneView.getParent();

            if (parent == null) {
                return false;
            } else if (parent == getStageActivity().getStageLayout()) {
                return true;
            } else {
                throw new IllegalStateException("Scene view should only be the child of stage layout");
            }
        }
    }

    // Add scene view to stage layout
    void attachToStage() {
        if (mSceneView != null && !isInStage()) {
            doAttachToStage();
        }
    }

    void attachToStageAsPreScene() {
        // TODO
    }

    // Remove scene view from stage layout
    void detachFromeStage() {
        if (mSceneView != null && isInStage()) {
            doDetachFromeStage();
        }
    }

    void doAttachToStage() {
        getStageActivity().attachSceneToStage(this);
    }

    void doAttachToStageAsPreScene() {
        getStageActivity().attachSceneToStageAsPreScene(this);
    }

    void doDetachFromeStage() {
        getStageActivity().detachSceneFromStage(this);
    }

    public void onBackPressed() {
        finish();
    }

    // It is constant
    private String getStateKey() {
        return "scene:" + Integer.toHexString(hashCode());
    }

    void saveInstanceState(Bundle outState) {
        SparseArray<Parcelable> states = new SparseArray<>();
        onSaveInstanceState(states);
        outState.putSparseParcelableArray(getStateKey(), states);
    }

    void restoreInstanceState(@NonNull Bundle savedInstanceState) {
        if (mSceneView != null) {
            SparseArray<Parcelable> savedStates
                    = savedInstanceState.getSparseParcelableArray(getStateKey());
            if (savedStates != null) {
                onRestoreInstanceState(savedStates);
            }
        }
    }

    protected void onSaveInstanceState(@NonNull SparseArray<Parcelable> outState) {
        if (mSceneView != null) {
            mSceneView.saveHierarchyState(outState);
        }
    }

    protected void onRestoreInstanceState(@NonNull SparseArray<Parcelable> savedStates) {
        if (mSceneView != null) {
            mSceneView.restoreHierarchyState(savedStates);
        }
    }

    public void startActivityForResult(Intent intent, ActivityResultListener listener) {
        getStageActivity().startActivityForResult(intent, listener);
    }

    /**
     * Return the FragmentManager for interacting with fragments associated
     * with StageActivity.
     */
    public FragmentManager getSupportFragmentManager() {
        return getStageActivity().getSupportFragmentManager();
    }

    public interface ActivityResultListener {
        public void onGetResult(int resultCode, Intent data);
    }
}