AdapterViewProtocols.java

package com.google.android.apps.common.testing.ui.espresso.action;

import static com.google.android.apps.common.testing.ui.espresso.matcher.ViewMatchers.isDisplayingAtLeast;
import static com.google.common.base.Preconditions.checkArgument;

import com.google.common.base.Optional;
import com.google.common.collect.Lists;
import com.google.common.collect.Range;

import android.os.Build;
import android.view.View;
import android.widget.AbsListView;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.AdapterViewAnimator;
import android.widget.AdapterViewFlipper;

import java.util.List;

/**
 * Implementations of {@link AdapterViewProtocol} for standard SDK Widgets.
 *
 */
public final class AdapterViewProtocols {

  /**
   * Consider views which have over this percentage of their area visible to the user
   * to be fully rendered.
   */
  private static final int FULLY_RENDERED_PERCENTAGE_CUTOFF = 90;

  private AdapterViewProtocols() {}

  private static final AdapterViewProtocol STANDARD_PROTOCOL = new StandardAdapterViewProtocol();

  /**
   * Creates an implementation of AdapterViewProtocol that can work with AdapterViews that do not
   * break method contracts on AdapterView.
   *
   */
  public static AdapterViewProtocol standardProtocol() {
    return STANDARD_PROTOCOL;
  }

  // TODO(user): expandablelistview protocols

  private static final class StandardAdapterViewProtocol implements AdapterViewProtocol {
    @Override
    public Iterable<AdaptedData> getDataInAdapterView(AdapterView<? extends Adapter> adapterView) {
      List<AdaptedData> datas = Lists.newArrayList();
      for (int i = 0; i < adapterView.getCount(); i++) {
        datas.add(
            new AdaptedData.Builder()
              .withData(adapterView.getItemAtPosition(i))
              .withOpaqueToken(i)
              .build());
      }
      return datas;
    }

    @Override
    public Optional<AdaptedData> getDataRenderedByView(AdapterView<? extends Adapter> adapterView,
        View descendantView) {
      if (adapterView == descendantView.getParent()) {
        int position = adapterView.getPositionForView(descendantView);
        if (position != AdapterView.INVALID_POSITION) {
          return Optional.of(new AdaptedData.Builder()
              .withData(adapterView.getItemAtPosition(position))
              .withOpaqueToken(Integer.valueOf(position))
              .build());
        }
      }
      return Optional.absent();
    }

    @Override
    public void makeDataRenderedWithinAdapterView(
        AdapterView<? extends Adapter> adapterView, AdaptedData data) {
      checkArgument(data.opaqueToken instanceof Integer, "Not my data: %s", data);
      int position = ((Integer) data.opaqueToken).intValue();

      boolean moved = false;
      // set selection should always work, we can give a little better experience if per subtype
      // though.
      if (Build.VERSION.SDK_INT > 7) {
        if (adapterView instanceof AbsListView) {
          if (Build.VERSION.SDK_INT > 10) {
            ((AbsListView) adapterView).smoothScrollToPositionFromTop(position,
                adapterView.getPaddingTop(), 0);
          } else {
            ((AbsListView) adapterView).smoothScrollToPosition(position);
          }
          moved = true;
        }
        if (Build.VERSION.SDK_INT > 10) {
          if (adapterView instanceof AdapterViewAnimator) {
            if (adapterView instanceof AdapterViewFlipper) {
              ((AdapterViewFlipper) adapterView).stopFlipping();
            }
            ((AdapterViewAnimator) adapterView).setDisplayedChild(position);
            moved = true;
          }
        }
      }
      if (!moved) {
        adapterView.setSelection(position);
      }
    }

    @SuppressWarnings("deprecation")
    @Override
    public boolean isDataRenderedWithinAdapterView(
        AdapterView<? extends Adapter> adapterView, AdaptedData adaptedData) {
      checkArgument(adaptedData.opaqueToken instanceof Integer, "Not my data: %s", adaptedData);
      int dataPosition = ((Integer) adaptedData.opaqueToken).intValue();

      if (Range.closed(adapterView.getFirstVisiblePosition(), adapterView.getLastVisiblePosition())
          .contains(dataPosition)) {
        if (adapterView.getFirstVisiblePosition() == adapterView.getLastVisiblePosition()) {
          // thats a huge element.
          return true;
        } else {
          return isElementFullyRendered(adapterView,
              dataPosition - adapterView.getFirstVisiblePosition());
        }
      } else {
        return false;
      }
    }

    private boolean isElementFullyRendered(AdapterView<? extends Adapter> adapterView,
        int childAt) {
      View element = adapterView.getChildAt(childAt);
      // Occassionally we'll have to fight with smooth scrolling logic on our definition of when
      // there is extra scrolling to be done. In particular if the element is the first or last
      // element of the list, the smooth scroller may decide that no work needs to be done to scroll
      // to the element if a certain percentage of it is on screen. Ugh. Sigh. Yuck.

      return isDisplayingAtLeast(FULLY_RENDERED_PERCENTAGE_CUTOFF).matches(element);
    }
  }
}