add android.widget.Adapter and related classes from AOSP

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

@@ -0,0 +1,79 @@
+/*
+ * 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.database.DataSetObservable;
+import android.database.DataSetObserver;
+import android.view.View;
+import android.view.ViewGroup;
+
+/**
+ * Common base class of common implementation for an {@link Adapter} that can be
+ * used in both {@link ListView} (by implementing the specialized
+ * {@link ListAdapter} interface} and {@link Spinner} (by implementing the
+ * specialized {@link SpinnerAdapter} interface.
+ */
+public abstract class BaseAdapter implements /*ListAdapter,*/ SpinnerAdapter {
+	private final DataSetObservable mDataSetObservable = new DataSetObservable();
+	public boolean hasStableIds() {
+		return false;
+	}
+
+	public void registerDataSetObserver(DataSetObserver observer) {
+		mDataSetObservable.registerObserver(observer);
+	}
+
+	public void unregisterDataSetObserver(DataSetObserver observer) {
+		mDataSetObservable.unregisterObserver(observer);
+	}
+
+	/**
+	 * Notifies the attached observers that the underlying data has been changed
+	 * and any View reflecting the data set should refresh itself.
+	 */
+	public void notifyDataSetChanged() {
+		mDataSetObservable.notifyChanged();
+	}
+
+	/**
+	 * Notifies the attached observers that the underlying data is no longer valid
+	 * or available. Once invoked this adapter is no longer valid and should
+	 * not report further data set changes.
+	 */
+	public void notifyDataSetInvalidated() {
+		mDataSetObservable.notifyInvalidated();
+	}
+	public boolean areAllItemsEnabled() {
+		return true;
+	}
+	public boolean isEnabled(int position) {
+		return true;
+	}
+	public View getDropDownView(int position, View convertView, ViewGroup parent) {
+		return getView(position, convertView, parent);
+	}
+	public int getItemViewType(int position) {
+		return 0;
+	}
+	public int getViewTypeCount() {
+		return 1;
+	}
+
+	public boolean isEmpty() {
+		return getCount() == 0;
+	}
+}