Android Open Source - 101AndroidApps Element Adapter

• Back to App/basic  ↑

From Project

Back to project page 101AndroidApps.

License

The source code is released under:

Licenced under the Creative Commons Attribution 4.0 licence. For full text see http://creativecommons.org/licenses/by/4.0/

Java Source Code

package com.hulzenga.ioi.android.app_005;
//from w w  w  . j av  a  2  s .  c om
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;

import com.hulzenga.ioi.android.app_005.ElementAdapter.ElementChangeObserver.ChangeType;

import java.util.HashMap;
import java.util.List;
import java.util.Map;

class ElementAdapter extends ArrayAdapter<Element> {


  private Context       mContext;
  private List<Element> mElements;
  private Map<Element, Integer> mElementIdMap   = new HashMap<>();
  private int                   mIdCount        = 0;
  private int                   mDraggedElement = -1;
  private ElementChangeObserver mElementChangeObserver;

  public ElementAdapter(Context context, int layoutViewId, List<Element> elements) {

    super(context, layoutViewId, elements);

    mContext = context;
    mElements = elements;

    allocateIds();
  }

  private void allocateIds() {
    mIdCount = mElements.size();

    for (int id = 0; id < mIdCount; id++) {
      mElementIdMap.put(mElements.get(id), id);
    }
  }

  public void registerElementChangeObserver(ElementChangeObserver observer) {
    mElementChangeObserver = observer;
  }

  @Override
  public void add(Element element) {
    mElements.add(0, element);
    mElementIdMap.put(element, mIdCount++);
    notifyElementChange(ChangeType.ELEMENT_ADDED);
  }

  /**
   * notifyElementChange notifies the ElementChangeObserver of changes in the
   * data.
   */
  public void notifyElementChange(ChangeType type, int... args) {
    if (mElementChangeObserver != null) {
      mElementChangeObserver.onElementChange(type, args);
    } else {
      throw new IllegalStateException("No ElementChangeObserver is registered!");
    }
  }

  @Override
  public Element getItem(int position) {
    return mElements.get(position);
  }

  @Override
  public long getItemId(int position) {
    return mElementIdMap.get(mElements.get(position));
  }

  public List<Element> getElements() {
    return mElements;
  }

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {

    ElementView elementView;
    if (convertView != null) {
      elementView = (ElementView) convertView;
      elementView.setPosition(position);
    } else {
      elementView = new ElementView(mContext, position);
    }

    if (position != mDraggedElement) {
      elementView.setImageBitmap(mElements.get(position).getIcon());
    } else {
      elementView.setImageBitmap(Element.getmEmptyIcon());
    }

    return elementView;
  }

  public void stopDragging() {
    mDraggedElement = -1;
    notifyElementChange(ChangeType.STOPPED_DRAGGING);
  }

  public void startDragging(int position) {
    mDraggedElement = position;
    notifyElementChange(ChangeType.STARTED_DRAGGING, position);
  }

  public void swap(int position1, int position2) {
    mDraggedElement = -1;

    Element e1 = getItem(position1);
    Element e2 = getItem(position2);

    mElements.set(position1, e2);
    mElements.set(position2, e1);

    notifyElementChange(ChangeType.ELEMENTS_SWAPPED, position1, position2);
  }

  public void removeItem(int position) {
    mElementIdMap.remove(mElements.get(position));
    mElements.remove(position);
    notifyElementChange(ChangeType.ELEMENT_REMOVED, position);
  }

  @Override
  public boolean hasStableIds() {
    return true;
  }

  // more practical observer for changes in the underlying dataset
  public interface ElementChangeObserver {
    public void onElementChange(ChangeType type, int... args);

    enum ChangeType {
      ELEMENT_ADDED, ELEMENT_REMOVED, STARTED_DRAGGING, STOPPED_DRAGGING, ELEMENTS_SWAPPED
    }
  }

}

Java Source Code List

• Back to App/basic  ↑