Android Open Source - RZAndroidBaseUtils View Holder Strategy Converter

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License

The source code is released under:

MIT License

Java Source Code

package com.raizlabs.widget.utils;
/*from  ww w.j av  a  2 s  .  co  m*/
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

/**
 * Abstract class which is a {@link ViewHolderStrategy} of one (source) type,
 * but uses a {@link ViewHolderStrategy} of a different (converted) type to
 * do the work. This works by having subclasses implement {@link #convert(Object)}
 * which maps the source type to the converted type. This allows easy implementation
 * of a {@link ViewHolderStrategy} of a type which wraps another type that you have
 * a {@link ViewHolderStrategy} for already.
 * <br><br>
 * For example, you may have a set of Dates you want to display as strings and
 * a strategy which displays strings. You can then extend this class with Date
 * as the source type, string as your converted type, and call the constructor
 * with your existing string {@link ViewHolderStrategy}. Then, you simply need
 * to implement {@link #convert(Object)} to take a Date and return the string to
 * display - likely via a DateFormat.
 * 
 * @author Dylan James
 *
 * @param <SourceItem> The source type that this {@link ViewHolderStrategyConverter}
 * will be passed, and acts as a {@link ViewHolderStrategy} for.
 * @param <ConvertedItem> The type that this {@link ViewHolderStrategyConverter} converts
 * to, and the existing {@link ViewHolderStrategy} knows how to interpret.
 * @param <Holder> The type of the {@link ViewHolder} that the converted
 * {@link ViewHolderStrategy} uses.
 */
public abstract class ViewHolderStrategyConverter<SourceItem, ConvertedItem, Holder>
implements ViewHolderStrategy<SourceItem, Holder> {
  
  ViewHolderStrategy<ConvertedItem, Holder> convertedStrategy;
  
  public ViewHolderStrategyConverter(ViewHolderStrategy<ConvertedItem, Holder> convertedTypeStrategy) {
    this.convertedStrategy = convertedTypeStrategy;
  }

  /**
   * Converts the source item into the converted type for the converted
   * {@link ViewHolderStrategy} to use.
   * @param item The item to convert.
   * @return The converted object to be passed to the converted {@link ViewHolderStrategy}.
   */
  protected abstract ConvertedItem convert(SourceItem item);

  @Override
  public boolean areAllItemsEnabled() {
    return convertedStrategy.areAllItemsEnabled();
  }

  @Override
  public boolean isEnabled(SourceItem item) {
    return convertedStrategy.isEnabled(convert(item));
  }

  @Override
  public int getItemViewType(SourceItem item) {
    return convertedStrategy.getItemViewType(convert(item));
  }

  @Override
  public int getViewTypeCount() {
    return convertedStrategy.getViewTypeCount();
  }

  @Override
  public View inflateView(SourceItem item, LayoutInflater inflater, ViewGroup root) {
    return convertedStrategy.inflateView(convert(item), inflater, root);
  }

  @Override
  public Holder createHolder(SourceItem item) {
    return convertedStrategy.createHolder(convert(item));
  }

  @Override
  public void populateHolder(View view, Holder holder) {
    convertedStrategy.populateHolder(view, holder);
  }

  @Override
  public void updateView(SourceItem item, Holder holder) {
    convertedStrategy.updateView(convert(item), holder);
  }
}

Java Source Code List

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