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Java classes to create a common base adapter strategy that acts as base for common adapters and multiple view types adapters in an android app
public abstract class BaseAllAdapters<T> extends BaseAdapter {
protected Context mContext;
protected LongSparseArray<DelegateAdapter> mDelegateAdapterSparseArray;
private int mViewLayoutId = 0;
private List<ListItem<T>> mItems;
/*Constructor if we dont use mutiple view types in the list*/
public BaseAllAdapters(Context context, int viewLayoutId) {
mContext = context;
mViewLayoutId = viewLayoutId;
}
/*Constructor if we use the delegateAdapter to create multiple view types in the list*/
public BaseAllAdapters(Context context, LongSparseArray<DelegateAdapter> delegateAdapterSparseArray) {
mContext = context;
Preconditions.checkNotNull(delegateAdapterSparseArray,"mDelegateAdapterSparseArray cannot be null");
Preconditions.checkState(delegateAdapterSparseArray.size()!=0,"mDelegateAdapterSparseArray cannot be empty using a multiple view type adapter, If you dont want to specify muliple views, please use the \"BaseAllAdapters(Context context, int viewLayoutId)\" constructor.");
}
public void clear() {
mItems.clear();
notifyDataSetChanged();
}
public List<T> getItems() {
List<T> listItems = new ArrayList<T>();
for (ListItem<T> listItem : mItems) {
listItems.add(listItem.getItem());
}
return listItems;
}
public void setItems(List<T> items) {
List<ListItem<T>> listItems = Utils.createListItemList(items);
if (!Objects.equal(items, mItems)) {
mItems = listItems;
notifyDataSetChanged();
}
}
@Override
public int getCount() {
return mItems != null ? mItems.size() : 0;
}
@Override
public ListItem<T> getItem(int position) {
return mItems.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
i
@Override
public View getView(int position, View convertView, ViewGroup parent) {
final ListItem<T> item = getItem(position);
ViewHolder holder;
if (convertView == null) {
if (isMultipleViewAdapter()) {
DelegateAdapter adapter = mDelegateAdapterSparseArray.get(getItemViewType(position));
convertView = adapter.getView(mContext, position, convertView, parent, LayoutInflater.from(mContext), getItem(position));
} else {
convertView = LayoutInflater.from(mContext).inflate(mViewLayoutId, parent, false);
}
holder = getHolderInstance(convertView);
if (holder == null) holder = new ViewHolder(convertView);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
bindView(position, convertView, item, holder);
return convertView;
}
private boolean isMultipleViewAdapter() {
return getViewTypeCount() > 1;
}
protected abstract void bindView(int position, View convertView, ListItem<T> item, ViewHolder parentHolder);
protected abstract ViewHolder getHolderInstance(View view);
public static class ViewHolder {
public ViewHolder(View view) {
ButterKnife.inject(this, view);
}
}
public static <T> List<ListItem<T>> createListItemList(final List<T> items) {
ArrayList<ListItem<T>> listItems = new ArrayList<ListItem<T>>(items.size());
for (T item : items) {
listItems.add(new ListItem<T>(item));
}
return listItems;
}
}
public abstract class BaseDelegateAdapter<T> implements DelegateAdapter<T> {
private final int mViewLayoutId;
protected BaseDelegateAdapter(int viewLayoutId) {
mViewLayoutId = viewLayoutId;
}
@Override
public View getView(Context context, int position, View convertView, ViewGroup parent, LayoutInflater inflater, ListItem<T> item) {
BaseAllAdapters.ViewHolder holder;
if (convertView == null) {
convertView = LayoutInflater.from(context).inflate(mViewLayoutId, parent, false);
holder = getHolderInstance(convertView);
if(holder== null) holder = new BaseAllAdapters.ViewHolder(convertView);
convertView.setTag(holder);
}else{
holder = (BaseAllAdapters.ViewHolder) convertView.getTag();
}
bindView(position, convertView, item, holder);
return convertView;
}
protected abstract void bindView(int position, View convertView, ListItem<T> item, BaseAllAdapters.ViewHolder parentHolder);
protected abstract BaseAllAdapters.ViewHolder getHolderInstance(View convertView);
}
public interface DelegateAdapter<T> {
public View getView(Context context, int position, View convertView, ViewGroup parent, LayoutInflater inflater, ListItem<T> item);
}
public class ListItem<T> {
public static final int TYPE_ITEM = 0;
public static final int TYPE_SECTION = 1;
private final int type;
private final T item;
private final String sectionTitle;
public ListItem(T item) {
type = TYPE_ITEM;
this.item = item;
sectionTitle = null;
}
public ListItem(String sectionTitle) {
type = TYPE_SECTION;
item = null;
this.sectionTitle = sectionTitle;
}
public int getType() {
return type;
}
public T getItem() {
return item;
}
public String getSectionTitle() {
return sectionTitle;
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
ListItem listItem = (ListItem) o;
if (type != listItem.type) {
return false;
}
if (item != null ? !item.equals(listItem.item) : listItem.item != null) {
return false;
}
return true;
}
@Override
public int hashCode() {
int result = type;
result = 31 * result + (item != null ? item.hashCode() : 0);
return result;
}
}
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