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Grid layout pager adapter
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| import android.content.Context; | |
| import android.view.View; | |
| import android.view.ViewGroup; | |
| import android.widget.ArrayAdapter; | |
| import android.widget.GridView; | |
| import androidx.annotation.NonNull; | |
| import androidx.annotation.Nullable; | |
| import androidx.viewpager.widget.PagerAdapter; | |
| import java.util.ArrayList; | |
| import java.util.Collections; | |
| import java.util.List; | |
| public abstract class GridPagerAdapter<T> extends PagerAdapter { | |
| private int columnCount, rowCount; | |
| private List<GridView> gridViews; | |
| private Context context; | |
| public GridPagerAdapter(Context context, int columnCount, int rowCount) { | |
| this.context = context; | |
| this.rowCount = rowCount; | |
| this.columnCount = columnCount; | |
| gridViews = new ArrayList<>(); | |
| } | |
| @Override | |
| public int getCount() { | |
| return gridViews.size(); | |
| } | |
| @Override | |
| public boolean isViewFromObject(@NonNull View view, @NonNull Object object) { | |
| return view == object; | |
| } | |
| @NonNull | |
| @Override | |
| public Object instantiateItem(@NonNull ViewGroup container, int position) { | |
| GridView view = gridViews.get(position); | |
| container.addView(view, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT)); | |
| return view; | |
| } | |
| @Override | |
| public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) { | |
| container.removeView((View) object); | |
| } | |
| @Override | |
| public void finishUpdate(@NonNull ViewGroup container) { | |
| super.finishUpdate(container); | |
| } | |
| protected Context getContext() { | |
| return context; | |
| } | |
| public void updatePageContents() { | |
| int maxItems = columnCount * rowCount; | |
| int pages = Math.round((float)getItemCount() / (float)maxItems); | |
| adjustPageCount(pages); | |
| int itemCount = 0; | |
| for (int i = 0; i < pages; i++) { | |
| List<T> pageItems = new ArrayList<>(); | |
| int max = itemCount + maxItems; //Math.min(itemCount + maxItems, getCount()); | |
| for (; itemCount < max; itemCount++) { | |
| try { | |
| pageItems.add(getItem(itemCount)); | |
| } catch (IndexOutOfBoundsException ignored) { | |
| break; | |
| } | |
| } | |
| setGridAdapter(pageItems, i); | |
| } | |
| } | |
| public abstract View getViewItem(T item, ViewGroup parent); | |
| public abstract T getItem(int pos); | |
| public abstract int getItemCount(); | |
| public void onItemClick(T item, View view) {} | |
| public boolean onItemLongClick(T item, View view) { | |
| return false; | |
| } | |
| private void setGridAdapter(List<T> items, int page) { | |
| gridViews.get(page).setAdapter(new GridAdapter(context, items)); | |
| } | |
| private void adjustPageCount(int pages) { | |
| if (gridViews.size() > pages) { | |
| while (gridViews.size() > pages) { | |
| gridViews.remove(gridViews.size() - 1); | |
| } | |
| } else if (gridViews.size() < pages) { | |
| while (gridViews.size() < pages) { | |
| GridView g = new GridView(context); | |
| g.setNumColumns(columnCount); | |
| gridViews.add(g); | |
| } | |
| } | |
| notifyDataSetChanged(); | |
| } | |
| class GridAdapter extends ArrayAdapter<T> { | |
| public GridAdapter(@NonNull Context context, List<T> items) { | |
| super(context, 0, items); | |
| } | |
| public GridAdapter(@NonNull Context context) { | |
| super(context, 0, Collections.<T>emptyList()); | |
| } | |
| @NonNull | |
| @Override | |
| public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) { | |
| final T item = getItem(position); | |
| View view = GridPagerAdapter.this.getViewItem(item, parent); | |
| view.setOnClickListener(new View.OnClickListener() { | |
| @Override | |
| public void onClick(View v) { | |
| onItemClick(item, v); | |
| } | |
| }); | |
| view.setOnLongClickListener(new View.OnLongClickListener() { | |
| @Override | |
| public boolean onLongClick(View v) { | |
| return onItemLongClick(item, v); | |
| } | |
| }); | |
| return view; | |
| } | |
| } | |
| } |
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