add android.widget.Adapter and related classes from AOSP

src/api-impl/android/widget/SpinnerAdapter.java

@@ -0,0 +1,43 @@
+/*
+ * Copyright (C) 2007 The Android Open Source Project
+ *
+ * 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 android.widget;
+
+import android.view.View;
+import android.view.ViewGroup;
+
+/**
+ * Extended {@link Adapter} that is the bridge between a
+ * {@link android.widget.Spinner} and its data. A spinner adapter allows to
+ * define two different views: one that shows the data in the spinner itself and
+ * one that shows the data in the drop down list when the spinner is pressed.</p>
+ */
+public interface SpinnerAdapter extends Adapter {
+	/**
+	 * <p>Get a {@link android.view.View} that displays in the drop down popup
+	 * the data at the specified position in the data set.</p>
+	 *
+	 * @param position      index of the item whose view we want.
+	 * @param convertView   the old view to reuse, if possible. Note: You should
+	 *        check that this view is non-null and of an appropriate type before
+	 *        using. If it is not possible to convert this view to display the
+	 *        correct data, this method can create a new view.
+	 * @param parent the parent that this view will eventually be attached to
+	 * @return a {@link android.view.View} corresponding to the data at the
+	 *         specified position.
+	 */
+	public View getDropDownView(int position, View convertView, ViewGroup parent);
+}