MirroringFragment.java

/***
  Copyright (c) 2013 CommonsWare, LLC
  
  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
  distributed under the License is distributed on an "AS IS" BASIS,
  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.commonsware.cwac.preso;

import android.app.Fragment;
import android.os.Bundle;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import com.commonsware.cwac.layouts.AspectLockedFrameLayout;
import com.commonsware.cwac.layouts.Mirror;
import com.commonsware.cwac.layouts.MirroringFrameLayout;

/**
 * Native fragment that mirrors its contents to the supplied Mirror.
 * This class is abstract; subclass it and override onCreateMirroredContent()
 * to provide the content to be mirrored.
 */
abstract public class MirroringFragment extends Fragment {
  /**
   * Override this to provide the content to be mirrored. Otherwise, it
   * works pretty much like onCreateView().
   *
   * @param inflater a LayoutInflater for your layout inflation convenience
   * @param container the ViewGroup that will hold the View that you return
   *                  (but do not add the View to the ViewGroup yourself, please)
   * @param savedInstanceState from a previous instance's onSaveInstanceState()
   * @return the View that you wish this fragment to mirror
   */
  abstract protected View onCreateMirroredContent(LayoutInflater inflater,
                                                  ViewGroup container,
                                                  Bundle savedInstanceState);

  private MirroringFrameLayout source=null;
  private AspectLockedFrameLayout aspectLock=null;

  /**
   * {@inheritDoc}
   */
  @Override
  final public View onCreateView(LayoutInflater inflater,
                                 ViewGroup container,
                                 Bundle savedInstanceState) {
    source=new MirroringFrameLayout(getActivity());
    source.addView(onCreateMirroredContent(inflater, source,
                                           savedInstanceState));

    aspectLock=new AspectLockedFrameLayout(getActivity());
    aspectLock.addView(source,
                       new FrameLayout.LayoutParams(
                                                    ViewGroup.LayoutParams.MATCH_PARENT,
                                                    ViewGroup.LayoutParams.MATCH_PARENT,
                                                    Gravity.CENTER));

    return(aspectLock);
  }

  /**
   * Call this to provide the Mirror that your designated content will
   * be mirrored to.
   *
   * @param mirror the Mirror
   */
  public void setMirror(Mirror mirror) {
    source.setMirror(mirror);
    aspectLock.setAspectRatioSource((View)mirror);
  }

  /**
   * Call this to provide the Mirror that your designated content will
   * be mirrored to. In this case, you are providing a MirrorPresentationFragment,
   * which itself is supplying the Mirror.
   *
   * @param mirrorFragment the MirrorPresentationFragment containing the Mirror
   *                       to be used for mirroring your designated content
   */
  public void setMirror(MirrorPresentationFragment mirrorFragment) {
    Mirror mirror=mirrorFragment.getMirror();

    if (mirror == null) {
      mirrorFragment.setMirroringFragment(this);
    }
    else if (source != null) {
      setMirror(mirror);
    }
  }

  /**
   * Call this to force your content to redraw and, hopefully, update the
   * associated Mirror. Ideally, this will not be needed, as change
   * detection should be automatic.
   */
  public void updateMirror() {
    source.invalidate();
  }
}