blob: 77f8327f2c2a39f5d05d61cff6e17724f31777c3 [file] [log] [blame]
/*
* Copyright (C) 2011 Google Inc.
* Licensed to 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 com.android.mailcommon;
import android.database.DataSetObserver;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListAdapter;
import android.widget.SpinnerAdapter;
import java.util.Arrays;
import java.util.List;
/**
* An adapter that combines items from multiple provided adapters into a single list.
*
* @param <T> the class of each constituent adapter
*/
public class MergedAdapter<T extends MergedAdapter.ListSpinnerAdapter> extends BaseAdapter {
private List<T> mAdapters;
private final DataSetObserver mObserver;
/**
* A Mergeable adapter must implement both ListAdapter and SpinnerAdapter to be useful in lists
* and spinners.
*/
public interface ListSpinnerAdapter extends ListAdapter, SpinnerAdapter {
}
public static class LocalAdapterPosition<T extends ListSpinnerAdapter> {
public final T mAdapter;
public final int mLocalPosition;
public LocalAdapterPosition(T adapter, int offset) {
mAdapter = adapter;
mLocalPosition = offset;
}
}
public MergedAdapter() {
mObserver = new DataSetObserver() {
@Override
public void onChanged() {
notifyDataSetChanged();
}
};
}
public void setAdapters(T... adapters) {
if (mAdapters != null) {
for (T adapter : mAdapters) {
adapter.unregisterDataSetObserver(mObserver);
}
}
mAdapters = Arrays.asList(adapters);
for (T adapter : mAdapters) {
adapter.registerDataSetObserver(mObserver);
}
}
public int getSubAdapterCount() {
return mAdapters.size();
}
public T getSubAdapter(int index) {
return mAdapters.get(index);
}
@Override
public int getCount() {
int count = 0;
for (T adapter : mAdapters) {
count += adapter.getCount();
}
return count;
// TODO: cache counts until next onChanged
}
/**
* For a given merged position, find the corresponding Adapter and local position within that
* Adapter by iterating through Adapters and summing their counts until the merged position is
* found.
*
* @param position a merged (global) position
* @return the matching Adapter and local position, or null if not found
*/
public LocalAdapterPosition<T> getAdapterOffsetForItem(final int position) {
final int adapterCount = mAdapters.size();
int i = 0;
int count = 0;
while (i < adapterCount) {
T a = mAdapters.get(i);
int newCount = count + a.getCount();
if (position < newCount) {
return new LocalAdapterPosition<T>(a, position - count);
}
count = newCount;
i++;
}
return null;
}
@Override
public Object getItem(int position) {
LocalAdapterPosition<T> result = getAdapterOffsetForItem(position);
if (result == null) {
return null;
}
return result.mAdapter.getItem(result.mLocalPosition);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public int getViewTypeCount() {
int count = 0;
for (T adapter : mAdapters) {
count += adapter.getViewTypeCount();
}
return count;
}
@Override
public int getItemViewType(int position) {
LocalAdapterPosition<T> result = getAdapterOffsetForItem(position);
int otherViewTypeCount = 0;
for (T adapter : mAdapters) {
if (adapter == result.mAdapter) {
break;
}
otherViewTypeCount += adapter.getViewTypeCount();
}
int type = result.mAdapter.getItemViewType(result.mLocalPosition);
// Headers (negative types) are in a separate global namespace and their values should not
// be affected by preceding adapter view types.
if (type >= 0) {
type += otherViewTypeCount;
}
return type;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
LocalAdapterPosition<T> result = getAdapterOffsetForItem(position);
return result.mAdapter.getView(result.mLocalPosition, convertView, parent);
}
@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
LocalAdapterPosition<T> result = getAdapterOffsetForItem(position);
return result.mAdapter.getDropDownView(result.mLocalPosition, convertView, parent);
}
@Override
public boolean areAllItemsEnabled() {
boolean enabled = true;
for (T adapter : mAdapters) {
enabled &= adapter.areAllItemsEnabled();
}
return enabled;
}
@Override
public boolean isEnabled(int position) {
LocalAdapterPosition<T> result = getAdapterOffsetForItem(position);
return result.mAdapter.isEnabled(result.mLocalPosition);
}
}