Java tutorial
/* * Copyright (C) 2016 based on The Android Open Source Project HeaderGridView * * 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. */ import android.content.Context; import android.database.DataSetObservable; import android.database.DataSetObserver; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentManager; import android.support.v4.app.FragmentTransaction; import android.util.AttributeSet; import android.view.View; import android.view.ViewGroup; import android.widget.AbsListView; import android.widget.AdapterView; import android.widget.Filter; import android.widget.Filterable; import android.widget.FrameLayout; import android.widget.LinearLayout; import android.widget.ListAdapter; import android.widget.ListView; import android.widget.RelativeLayout; import android.widget.WrapperListAdapter; /** * * @author ahmedb * * listView that support adding banner as first item or not as it will * act as a normal listView to use this class all you have to do is to * pass a fragment or a normal view as a banner and that is it * */ public class BannerListView extends ListView { // id for fragment adding to view private static final int CONTAINER_ID = 1215; // array of headers private FixedViewInfo mBannerView; // init views public BannerListView(Context context) { super(context); } public BannerListView(Context context, AttributeSet attrs) { super(context, attrs); } public BannerListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } /** * * @author ahmedb * * subclass of frameLayout to get full width of screen * since banner will be full width * */ private class FullWidthFixedViewLayout extends FrameLayout { public FullWidthFixedViewLayout(Context context) { super(context); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { int targetWidth = this.getMeasuredWidth() - this.getPaddingLeft() - this.getPaddingRight(); widthMeasureSpec = MeasureSpec.makeMeasureSpec(targetWidth, MeasureSpec.getMode(widthMeasureSpec)); super.onMeasure(widthMeasureSpec, heightMeasureSpec); } } /** * this method take supported fragment and fragment activity to add that * fragment as a banner to listView it create a layout at runtime then when * view is added to list we replace it with fragment otherwise it will crash * since view is not on screen to be replaced * * @param fragment * @param activity */ public void addBannerFragment(final Fragment fragment, final FragmentActivity activity) { LinearLayout layout = new LinearLayout(activity); AbsListView.LayoutParams param = new AbsListView.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT); layout.setLayoutParams(param); layout.setId(CONTAINER_ID); addLayoutContainer(layout); this.addOnLayoutChangeListener(new OnLayoutChangeListener() { @Override public void onLayoutChange(View v, int left, int top, int right, int bottom, int oldLeft, int oldTop, int oldRight, int oldBottom) { BannerListView.this.removeOnLayoutChangeListener(this); FragmentManager manager = activity.getSupportFragmentManager(); FragmentTransaction transaction = manager.beginTransaction(); transaction.add(CONTAINER_ID, fragment).commit(); } }); } /** * this method a view to be added as a banner to listView * */ public void addHeaderView(View v) { addLayoutContainer(v); } /** * a method that take view and add it to list in case we add fragment it * take a linear layout as a container to fragment else it will leave the * passed view as it is * * @param view */ private void addLayoutContainer(View view) { ListAdapter adapter = getAdapter(); if (adapter != null && !(adapter instanceof HeaderViewListAdapter)) { throw new IllegalStateException( "Cannot add header view to grid -- setAdapter has already been called."); } FixedViewInfo info = new FixedViewInfo(); // FrameLayout fl = new FullWidthFixedViewLayout(getContext()); // fl.addView(view); info.view = view; mBannerView = info; // mHeaderViewInfos.add(info); // in the case of re-adding a header view, or adding one later on, // we need to notify the observer if (adapter != null) { ((HeaderViewListAdapter) adapter).notifyDataSetChanged(); } } /** * * @return 1 if there is a header else return 0 */ public int getHeaderViewCount() { return mBannerView != null ? 1 : 0; } /** * this method take the passed adapter and check if there is a header it * will pass adapter to another custom adapter else it will act as a normal * listView */ @Override public void setAdapter(ListAdapter adapter) { if (mBannerView != null) { HeaderViewListAdapter hadapter = new HeaderViewListAdapter(mBannerView, adapter); super.setAdapter(hadapter); } else { super.setAdapter(adapter); } } /** * * @author ahmedb * * custom adapter that take a banner and an adapter if there is * header it will add it as first view and return the passed adapter * for all other positions */ private static class HeaderViewListAdapter implements WrapperListAdapter, Filterable { private final DataSetObservable mDataSetObservable = new DataSetObservable(); private final ListAdapter mAdapter; // This ArrayList is assumed to NOT be null. FixedViewInfo mHeader; private final boolean mIsFilterable; public HeaderViewListAdapter(FixedViewInfo headerViewInfos, ListAdapter adapter) { mAdapter = adapter; mIsFilterable = adapter instanceof Filterable; if (headerViewInfos == null) { throw new IllegalArgumentException("headerViewInfos cannot be null"); } mHeader = headerViewInfos; } public int getHeadersCount() { return mHeader != null ? 1 : 0; } @Override public boolean areAllItemsEnabled() { if (mAdapter != null) { return mAdapter.areAllItemsEnabled(); } else { return true; } } @Override public boolean isEnabled(int position) { int numHeadersAndPlaceholders = getHeadersCount(); if (position < numHeadersAndPlaceholders) { return true; } // Adapter final int adjPosition = position - numHeadersAndPlaceholders; int adapterCount = 0; if (mAdapter != null) { adapterCount = mAdapter.getCount(); if (adjPosition < adapterCount) { return mAdapter.isEnabled(adjPosition); } } throw new ArrayIndexOutOfBoundsException(position); } /** * return total numbers of items (header + passed adapter count) else * return number of header only */ @Override public int getCount() { if (mAdapter != null) { return getHeadersCount() + mAdapter.getCount(); } else { return getHeadersCount(); } } /** * return item at that position if position == 0 it will return header * else it will adjust position (i.e position - 1) and return that item */ @Override public Object getItem(int position) { int numHeadersAndPlaceholders = getHeadersCount(); if (position < numHeadersAndPlaceholders) { if (position == 0) { return mHeader.data; } return null; } // Adapter final int adjPosition = position - numHeadersAndPlaceholders; int adapterCount = 0; if (mAdapter != null) { adapterCount = mAdapter.getCount(); if (adjPosition < adapterCount) { return mAdapter.getItem(adjPosition); } } throw new ArrayIndexOutOfBoundsException(position); } @Override public long getItemId(int position) { int numHeadersAndPlaceholders = getHeadersCount(); if (mAdapter != null && position >= numHeadersAndPlaceholders) { int adjPosition = position - numHeadersAndPlaceholders; int adapterCount = mAdapter.getCount(); if (adjPosition < adapterCount) { return mAdapter.getItemId(adjPosition); } } return -1; } @Override public int getItemViewType(int position) { int numHeadersAndPlaceholders = getHeadersCount(); if (position < numHeadersAndPlaceholders) { return mAdapter != null ? mAdapter.getViewTypeCount() : 1; } if (mAdapter != null && position >= numHeadersAndPlaceholders) { int adjPosition = position - numHeadersAndPlaceholders; int adapterCount = mAdapter.getCount(); if (adjPosition < adapterCount) { return mAdapter.getItemViewType(adjPosition); } } return AdapterView.ITEM_VIEW_TYPE_HEADER_OR_FOOTER; } @Override public View getView(int position, View convertView, ViewGroup parent) { int numHeadersAndPlaceholders = getHeadersCount(); if (position < numHeadersAndPlaceholders) { View headerViewContainer = mHeader.view; if (position == 0) { return headerViewContainer; } } // Adapter final int adjPosition = position - numHeadersAndPlaceholders; int adapterCount = 0; if (mAdapter != null) { adapterCount = mAdapter.getCount(); if (adjPosition < adapterCount) { return mAdapter.getView(adjPosition, convertView, parent); } } throw new ArrayIndexOutOfBoundsException(position); } @Override public int getViewTypeCount() { if (mAdapter != null) { return mAdapter.getViewTypeCount() + 1; } return 2; } @Override public boolean hasStableIds() { if (mAdapter != null) { return mAdapter.hasStableIds(); } return false; } @Override public boolean isEmpty() { return (mAdapter == null || mAdapter.isEmpty()) && getHeadersCount() == 0; } @Override public void registerDataSetObserver(DataSetObserver observer) { mDataSetObservable.registerObserver(observer); if (mAdapter != null) { mAdapter.registerDataSetObserver(observer); } } @Override public void unregisterDataSetObserver(DataSetObserver observer) { mDataSetObservable.unregisterObserver(observer); if (mAdapter != null) { mAdapter.unregisterDataSetObserver(observer); } } @Override public Filter getFilter() { if (mIsFilterable) { return ((Filterable) mAdapter).getFilter(); } return null; } @Override public ListAdapter getWrappedAdapter() { return mAdapter; } public void notifyDataSetChanged() { mDataSetObservable.notifyChanged(); } } }