diff options
author | The Android Open Source Project <initial-contribution@android.com> | 2008-10-21 07:00:00 -0700 |
---|---|---|
committer | The Android Open Source Project <initial-contribution@android.com> | 2008-10-21 07:00:00 -0700 |
commit | 54b6cfa9a9e5b861a9930af873580d6dc20f773c (patch) | |
tree | 35051494d2af230dce54d6b31c6af8fc24091316 /core/java/android/widget/Adapter.java | |
download | frameworks_base-54b6cfa9a9e5b861a9930af873580d6dc20f773c.zip frameworks_base-54b6cfa9a9e5b861a9930af873580d6dc20f773c.tar.gz frameworks_base-54b6cfa9a9e5b861a9930af873580d6dc20f773c.tar.bz2 |
Initial Contribution
Diffstat (limited to 'core/java/android/widget/Adapter.java')
-rw-r--r-- | core/java/android/widget/Adapter.java | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/core/java/android/widget/Adapter.java b/core/java/android/widget/Adapter.java new file mode 100644 index 0000000..e952dd5 --- /dev/null +++ b/core/java/android/widget/Adapter.java @@ -0,0 +1,149 @@ +/* + * Copyright (C) 2006 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.DataSetObserver; +import android.view.KeyEvent; +import android.view.View; +import android.view.ViewGroup; + +/** + * An Adapter object acts as a bridge between an {@link AdapterView} and the + * underlying data for that view. The Adapter provides access to the data items. + * The Adapter is also responsible for making a {@link android.view.View} for + * each item in the data set. + * + * @see android.widget.ArrayAdapter + * @see android.widget.CursorAdapter + * @see android.widget.SimpleCursorAdapter + */ +public interface Adapter { + /** + * Register an observer that is called when changes happen to the data used by this adapter. + * + * @param observer the object that gets notified when the data set changes. + */ + void registerDataSetObserver(DataSetObserver observer); + + /** + * Unregister an observer that has previously been registered with this + * adapter via {@link #registerDataSetObserver}. + * + * @param observer the object to unregister. + */ + void unregisterDataSetObserver(DataSetObserver observer); + + /** + * How many items are in the data set represented by this Adapter. + * + * @return Count of items. + */ + int getCount(); + + /** + * Get the data item associated with the specified position in the data set. + * + * @param position Position of the item whose data we want within the adapter's + * data set. + * @return The data at the specified position. + */ + Object getItem(int position); + + /** + * Get the row id associated with the specified position in the list. + * + * @param position The position of the item within the adapter's data set whose row id we want. + * @return The id of the item at the specified position. + */ + long getItemId(int position); + + /** + * Indicated whether the item ids are stable across changes to the + * underlying data. + * + * @return True if the same id always refers to the same object. + */ + boolean hasStableIds(); + + /** + * Get a View that displays the data at the specified position in the data set. You can either + * create a View manually or inflate it from an XML layout file. When the View is inflated, the + * parent View (GridView, ListView...) will apply default layout parameters unless you use + * {@link android.view.LayoutInflater#inflate(int, android.view.ViewGroup, boolean)} + * to specify a root view and to prevent attachment to the root. + * + * @param position The position of the item within the adapter's data set 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 View corresponding to the data at the specified position. + */ + View getView(int position, View convertView, ViewGroup parent); + + /** + * An item view type that causes the {@link AdapterView} to ignore the item + * view. For example, this can be used if the client does not want a + * particular view to be given for conversion in + * {@link #getView(int, View, ViewGroup)}. + * + * @see #getItemViewType(int) + * @see #getViewTypeCount() + */ + static final int IGNORE_ITEM_VIEW_TYPE = AdapterView.ITEM_VIEW_TYPE_IGNORE; + + /** + * Get the type of View that will be created by {@link #getView} for the specified item. + * + * @param position The position of the item within the adapter's data set whose view type we + * want. + * @return An integer representing the type of View. Two views should share the same type if one + * can be converted to the other in {@link #getView}. Note: Integers must be in the + * range 0 to {@link #getViewTypeCount} - 1. {@link #IGNORE_ITEM_VIEW_TYPE} can + * also be returned. + * @see IGNORE_ITEM_VIEW_TYPE + */ + int getItemViewType(int position); + + /** + * <p> + * Returns the number of types of Views that will be created by + * {@link #getView}. Each type represents a set of views that can be + * converted in {@link #getView}. If the adapter always returns the same + * type of View for all items, this method should return 1. + * </p> + * <p> + * This method will only be called when when the adapter is set on the + * the {@link AdapterView}. + * </p> + * + * @return The number of types of Views that will be created by this adapter + */ + int getViewTypeCount(); + + static final int NO_SELECTION = Integer.MIN_VALUE; + + /** + * @return true if this adapter doesn't contain any data. This is used to determine + * whether the empty view should be displayed. A typical implementation will return + * getCount() == 0 but since getCount() includes the headers and footers, specialized + * adapters might want a different behavior. + */ + boolean isEmpty(); +} + |