android.support.v7.widget.StaggeredGridLayoutManager#VERTICAL源码实例Demo

private void initRecycleView(){
    final StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL);
    mRcvIndexContent.setLayoutManager(layoutManager);
    mAdapter = new ViewListAdapter(this);
    mAdapter.setIClickItem(this);
    mRcvIndexContent.setAdapter(mAdapter);

    mRcvIndexContent.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);
            boolean isBottom =
                    layoutManager.findLastCompletelyVisibleItemPositions(new int[2])[1]
                            >= mAdapter.getItemCount() - 4;
            if (!mSwipeRefreshLayout.isRefreshing() && isBottom && mHasMoreData) {
                showRefresh();
                mPresenter.getDataMore();
            }
        }
    });
}
 

@Override
public void initSubViews(View view) {
    super.initSubViews(view);
    staggeredGridLayoutManager = new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
    meiziAdapter = new FooterRecyclerAdapter<>(new MeiziAdapter());
    recyclerView.setLayoutManager(staggeredGridLayoutManager);
    recyclerView.setAdapter(meiziAdapter);
    scrollListener = new BaseRecyclerOnScrollListener(staggeredGridLayoutManager) {
        @Override
        public void onLoadMore(int currentPage) {
            mPresenter.requestMeizi(currentPage);
        }
    };
    recyclerView.addOnScrollListener(scrollListener);
    swipeRefreshLayout.setOnRefreshListener(this);
}
 

private void refreshRecyclerView(int column) {

        MyAdapter myAdapter = new MyAdapter(MainActivity.this);
        HeaderAndFooterRecyclerViewAdapter adapter = new HeaderAndFooterRecyclerViewAdapter(myAdapter);
        recyclerView.setAdapter(adapter);

        ExStaggeredGridLayoutManager staggeredGridLayoutManager = new ExStaggeredGridLayoutManager(column, StaggeredGridLayoutManager.VERTICAL);
        staggeredGridLayoutManager.setSpanSizeLookup(new HeaderSpanSizeLookup((HeaderAndFooterRecyclerViewAdapter) recyclerView.getAdapter(), staggeredGridLayoutManager.getSpanCount()));
        recyclerView.setLayoutManager(staggeredGridLayoutManager);

        View headerView = LayoutInflater.from(MainActivity.this).inflate(R.layout.layout_header, null);
        View footerView = LayoutInflater.from(MainActivity.this).inflate(R.layout.layout_footer, null);

        RecyclerViewUtils.setHeaderView(recyclerView, headerView);
        RecyclerViewUtils.setFooterView(recyclerView, footerView);
    }
 

private void initRecycler(ImageStreamAdapter adapter) {
    final int columns = bottomSheet.getContext().getResources().getInteger(R.integer.belvedere_image_stream_column_count);
    final StaggeredGridLayoutManager staggeredGridLayoutManager =
            new StaggeredGridLayoutManager(columns, StaggeredGridLayoutManager.VERTICAL);

    imageList.setLayoutManager(staggeredGridLayoutManager);
    imageList.setHasFixedSize(true);
    imageList.setDrawingCacheEnabled(true);
    imageList.setDrawingCacheQuality(View.DRAWING_CACHE_QUALITY_HIGH);

    final DefaultItemAnimator defaultItemAnimator = new DefaultItemAnimator();
    defaultItemAnimator.setSupportsChangeAnimations(false);
    imageList.setItemAnimator(defaultItemAnimator);

    imageList.setAdapter(adapter);
}
 

/**
 * 判断是否是最后一列
 */
private boolean isLastColumn(RecyclerView parent, int pos, int spanCount, int childCount) {
    RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
    if (layoutManager instanceof GridLayoutManager) {
        if ((pos + 1) % spanCount == 0) {// 如果是最后一列，则不需要绘制右边
            return true;
        }
    } else if (layoutManager instanceof StaggeredGridLayoutManager) {
        int orientation = ((StaggeredGridLayoutManager) layoutManager)
                .getOrientation();
        if (orientation == StaggeredGridLayoutManager.VERTICAL) {
            if ((pos + 1) % spanCount == 0) {// 如果是最后一列，则不需要绘制右边
                return true;
            }
        } else {
            childCount = childCount - childCount % spanCount;
            if (pos >= childCount) {// 如果是最后一列，则不需要绘制右边
                return true;
            }
        }
    }
    return false;
}
 

private boolean isLastColum(RecyclerView parent, int pos, int spanCount,
                            int childCount) {
    RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
    if (layoutManager instanceof GridLayoutManager) {
        if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
        {
            return true;
        }
    } else if (layoutManager instanceof StaggeredGridLayoutManager) {
        int orientation = ((StaggeredGridLayoutManager) layoutManager)
                .getOrientation();
        if (orientation == StaggeredGridLayoutManager.VERTICAL) {
            if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
            {
                return true;
            }
        } else {
            childCount = childCount - childCount % spanCount;
            if (pos >= childCount)// 如果是最后一列，则不需要绘制右边
                return true;
        }
    }
    return false;
}
 

private boolean isLastRaw(RecyclerView parent, int pos, int spanCount, int childCount) {
	RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
	if (layoutManager instanceof GridLayoutManager) {
		childCount = childCount - childCount % spanCount;
		if (pos >= childCount)// 如果是最后一行，则不需要绘制底部
			return true;
	} else if (layoutManager instanceof StaggeredGridLayoutManager) {
		int orientation = ((StaggeredGridLayoutManager) layoutManager).getOrientation();
		// StaggeredGridLayoutManager 且纵向滚动
		if (orientation == StaggeredGridLayoutManager.VERTICAL) {
			childCount = childCount - childCount % spanCount;
			// 如果是最后一行，则不需要绘制底部
			if (pos >= childCount)
				return true;
		} else
		// StaggeredGridLayoutManager 且横向滚动
		{
			// 如果是最后一行，则不需要绘制底部
			if ((pos + 1) % spanCount == 0) {
				return true;
			}
		}
	}
	return false;
}
 

@Override
protected ILayoutManager getLayoutManager() {
    random = new Random().nextInt(3);
    switch (random) {
        case 0:
            return new MyLinearLayoutManager(getContext());
        case 1:
            return new MyGridLayoutManager(getContext(), 3);
        case 2:
            return new MyStaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);
    }
    return super.getLayoutManager();
}
 

private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,
                          int childCount) {
    RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
    if (layoutManager instanceof GridLayoutManager) {
        childCount = childCount - childCount % spanCount;
        if (pos >= childCount)// 如果是最后一行，则不需要绘制底部
            return true;
    }
    else if (layoutManager instanceof StaggeredGridLayoutManager) {

        int orientation = ((StaggeredGridLayoutManager) layoutManager)
                .getOrientation();
        // StaggeredGridLayoutManager 且纵向滚动
        if (orientation == StaggeredGridLayoutManager.VERTICAL) {
            childCount = childCount - childCount % spanCount;
            // 如果是最后一行，则不需要绘制底部
            if (pos >= childCount)
                return true;
        }
        else {
            // 如果是最后一行，则不需要绘制底部
            if ((pos + 1) % spanCount == 0) {
                return true;
            }
        }
    }
    return false;
}
 

private void initView(){
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    coordinatorLayout=(CoordinatorLayout)findViewById(R.id.behavior_demo_coordinatorLayout);

    recyclerview=(RecyclerView)findViewById(R.id.behavior_demo_recycler);
    mLayoutManager=new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
    recyclerview.setLayoutManager(mLayoutManager);

    swipeRefreshLayout=(SwipeRefreshLayout) findViewById(R.id.behavior_demo_swipe_refresh) ;
    swipeRefreshLayout.setProgressViewOffset(false, 0,  (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 24, getResources().getDisplayMetrics()));//调整下拉控件位置

    fab=(FloatingActionButton) findViewById(R.id.fab);
}
 

private boolean isLastRaw(RecyclerView parent, int pos, int spanCount,
        int childCount)
{
    LayoutManager layoutManager = parent.getLayoutManager();
    if (layoutManager instanceof GridLayoutManager)
    {
        childCount = childCount - childCount % spanCount;
        if (pos >= childCount)// 如果是最后一行，则不需要绘制底部
            return true;
    } else if (layoutManager instanceof StaggeredGridLayoutManager)
    {
        int orientation = ((StaggeredGridLayoutManager) layoutManager)
                .getOrientation();
        // StaggeredGridLayoutManager 且纵向滚动
        if (orientation == StaggeredGridLayoutManager.VERTICAL)
        {
            childCount = childCount - childCount % spanCount;
            // 如果是最后一行，则不需要绘制底部
            if (pos >= childCount)
                return true;
        } else
        // StaggeredGridLayoutManager 且横向滚动
        {
            // 如果是最后一行，则不需要绘制底部
            if ((pos + 1) % spanCount == 0)
            {
                return true;
            }
        }
    }
    return false;
}
 

private boolean isLastColum(RecyclerView parent, int pos, int spanCount,
                            int childCount)
{
    LayoutManager layoutManager = parent.getLayoutManager();
    if (layoutManager instanceof GridLayoutManager)
    {
        if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
        {
            return true;
        }
    } else if (layoutManager instanceof StaggeredGridLayoutManager)
    {
        int orientation = ((StaggeredGridLayoutManager) layoutManager)
                .getOrientation();
        if (orientation == StaggeredGridLayoutManager.VERTICAL)
        {
            if ((pos + 1) % spanCount == 0)// 如果是最后一列，则不需要绘制右边
            {
                return true;
            }
        } else
        {
            childCount = childCount - childCount % spanCount;
            if (pos >= childCount)// 如果是最后一列，则不需要绘制右边
                return true;
        }
    }
    return false;
}
 

@Override
public void setupView(){
    int itemSpace = (int) getResources().getDimension( R.dimen.default_padding_margin );
    rvBeer.addItemDecoration( new StaggeredGridLayoutMargin( COLUMN, itemSpace ) );
    StaggeredGridLayoutManager layout = new StaggeredGridLayoutManager( COLUMN, StaggeredGridLayoutManager.VERTICAL );
    rvBeer.setLayoutManager( layout );
    rvBeer.setAdapter( beerAdapter );

    btnTryAgain.setOnClickListener( onClickTryAgain() );
}
 

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_refresh_view);
    recyclerView = findViewById(R.id.recyclerView);

    adapter = new ImageStageredAdapter(this);
    recyclerView.setAdapter(adapter);
    StaggeredGridLayoutManager staggeredGridLayoutManager =
            new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
    recyclerView.setLayoutManager(staggeredGridLayoutManager);
    SpaceViewItemLine itemDecoration = new SpaceViewItemLine(20);
    recyclerView.addItemDecoration(itemDecoration);


    adapter.addHeader(new InterItemView() {
        @Override
        public View onCreateView(ViewGroup parent) {
            BannerView header = new BannerView(SevenStaggeredActivity.this);
            header.setHintView(new ColorPointHintView(SevenStaggeredActivity.this, Color.YELLOW,Color.GRAY));
            header.setHintPadding(0, 0, 0, (int) AppUtils.convertDpToPixel(8, SevenStaggeredActivity.this));
            header.setPlayDelay(2000);
            header.setLayoutParams(new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, (int) AppUtils.convertDpToPixel(200, SevenStaggeredActivity.this)));
            header.setAdapter(new BannerAdapter(SevenStaggeredActivity.this));
            return header;
        }

        @Override
        public void onBindView(View headerView) {

        }
    });
    adapter.setMore(R.layout.view_more, new OnMoreListener() {
        @Override
        public void onMoreShow() {
            addData();
        }

        @Override
        public void onMoreClick() {

        }
    });
    adapter.setNoMore(R.layout.view_nomore);
    recyclerView.setRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
        @Override
        public void onRefresh() {
            recyclerView.postDelayed(new Runnable() {
                @Override
                public void run() {
                    adapter.clear();
                    adapter.addAll(DataProvider.getPictures());
                }
            },1000);
        }
    });
    addData();
}
 

@Override
public void onCreateViewEvent(LayoutInflater inflater, final ViewGroup container, Bundle savedInstanceState) {
    rootView = inflater.inflate(R.layout.fragment_call_events, container, false);

    setHasOptionsMenu(true);

    recyclerViewCalls = (RecyclerView) rootView.findViewById(R.id.recyclerView);
    callRecyclerViewAdapter = new CallRecyclerViewAdapter(getActivity(), callEvents);
    recyclerViewCalls.setAdapter(callRecyclerViewAdapter);
    StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(
            getSpanCount(), StaggeredGridLayoutManager.VERTICAL);
    recyclerViewCalls.setLayoutManager(layoutManager);

    final RecyclerViewFragment recyclerViewFragment = this;

    fab = (FloatingActionButton) rootView.findViewById(R.id.add_fab);
    fab.setImageDrawable(IconicsHelper.getAddIcon(getActivity(), ContextCompat.getColor(getActivity(), android.R.color.white)));
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (!PermissionHelper.isPhonePermissionAvailable(getContext())) {
                new AlertDialog.Builder(getContext())
                        .setTitle(R.string.missing_permission)
                        .setMessage(R.string.missing_contacts_permission)
                        .setNeutralButton(R.string.close, null)
                        .show();
                return;
            }

            ConfigureCallEventDialog configureCallEventDialog = new ConfigureCallEventDialog();
            configureCallEventDialog.setTargetFragment(recyclerViewFragment, 0);
            configureCallEventDialog.show(getFragmentManager(), null);
        }
    });

    // BroadcastReceiver to get notifications from background service if room data has changed
    broadcastReceiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            Log.d(this, "received intent: " + intent.getAction());

            switch (intent.getAction()) {
                case LocalBroadcastConstants.INTENT_CALL_EVENTS_CHANGED:
                    refreshCalls();
                    break;
                case LocalBroadcastConstants.INTENT_PERMISSION_CHANGED:
                    int permissionRequestCode = intent.getIntExtra(PermissionConstants.KEY_REQUEST_CODE, 0);
                    int[] result = intent.getIntArrayExtra(PermissionConstants.KEY_RESULTS);

                    if (permissionRequestCode == PermissionConstants.REQUEST_CODE_PHONE_PERMISSION) {
                        boolean allGranted = true;
                        for (int i = 0; i < result.length; i++) {
                            allGranted &= result[i] == PackageManager.PERMISSION_GRANTED;
                        }

                        if (allGranted) {
                            StatusMessageHandler.showInfoMessage(getRecyclerView(),
                                    R.string.permission_granted, Snackbar.LENGTH_SHORT);

                            sendCallEventsChangedBroadcast(context);
                        } else {
                            StatusMessageHandler.showPermissionMissingMessage(getActivity(),
                                    getRecyclerView(),
                                    Manifest.permission.READ_PHONE_STATE, Manifest.permission.READ_CONTACTS);
                        }
                    }
                    break;
            }
        }
    };
}
 

public void init() {
    View header = LayoutInflater.from(this).inflate(R.layout.layout_header, null);

    normalAdapterManager = new BindSuperAdapterManager();
    normalAdapterManager
            .bind(BindImageModel.class, BindImageHolder.ID, BindImageHolder.class)
            .bind(BindTextModel.class, BindTextHolder.ID, BindTextHolder.class)
            .bind(BindMutliModel.class, BindMutliHolder.ID, BindMutliHolder.class)
            .bind(BindClickModel.class, BindClickHolder.ID, BindClickHolder.class)
            .bindEmpty(BindNoDataHolder.NoDataModel.class, BindNoDataHolder.ID, BindNoDataHolder.class)
            .setNeedAnimation(true)
            .setOnItemClickListener(new OnItemClickListener() {
                @Override
                public void onItemClick(Context context, int position) {
                    //需要减去你的header和刷新的view的数量
                    Toast.makeText(context, "点击了！！　" + position, Toast.LENGTH_SHORT).show();
                }
            })
            .addHeaderView(header)
            .setPullRefreshEnabled(true)
            .setLoadingMoreEnabled(true)
            .setFootView(new BindCustomLoadMoreFooter(this))
            .setRefreshHeader(new BindCustomRefreshHeader(this))
            .setLoadingListener(new OnLoadingListener() {
                @Override
                public void onRefresh() {
                    recycler.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            refresh();
                        }
                    }, 3000);
                }

                @Override
                public void onLoadMore() {
                    recycler.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                            loadMore();
                        }
                    }, 2000);
                }
            });
    ;

    adapter = new BindSuperAdapter(this, normalAdapterManager, datas);


    //瀑布流管理器
    StaggeredGridLayoutManager staggeredGridLayoutManager = new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
    //staggeredGridLayoutManager.setReverseLayout(true);
    recycler.setLayoutManager(staggeredGridLayoutManager);

    //使能拖拽
    /*BindDragCallBack bindDragCallBack = new BindDragCallBack(adapter);
    ItemTouchHelper itemTouchHelper = new ItemTouchHelper(bindDragCallBack);
    itemTouchHelper.attachToRecyclerView(recycler);*/


    //间隔线
    recycler.addItemDecoration(new BindDecorationBuilder(adapter)
            .setColor(getResources()
            .getColor(R.color.material_deep_teal_500))
            .setSpace(dip2px(this, 5))
            .setNeedGridRightLeftEdge(true)
            .setNeedFirstTopEdge(true)
            .builder());

    recycler.setAdapter(adapter);


}
 

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_cards);

    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);


    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setDisplayShowHomeEnabled(true);

    //check Internet Connection
    new CheckInternetConnection(this).checkConnection();

    //Initializing our Recyclerview
    mRecyclerView = findViewById(R.id.my_recycler_view);
    tv_no_item = findViewById(R.id.tv_no_cards);


    if (mRecyclerView != null) {
        //to enable optimization of recyclerview
        mRecyclerView.setHasFixedSize(true);
    }
    //using staggered grid pattern in recyclerview
    mLayoutManager = new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
    mRecyclerView.setLayoutManager(mLayoutManager);

    //Say Hello to our new FirebaseUI android Element, i.e., FirebaseRecyclerAdapter
    final FirebaseRecyclerAdapter<GenericProductModel,Cards.MovieViewHolder> adapter = new FirebaseRecyclerAdapter<GenericProductModel, Cards.MovieViewHolder>(
            GenericProductModel.class,
            R.layout.cards_cardview_layout,
            Cards.MovieViewHolder.class,
            //referencing the node where we want the database to store the data from our Object
            mDatabaseReference.child("Products").child("Tshirt").getRef()
    ) {
        @Override
        protected void populateViewHolder(final Cards.MovieViewHolder viewHolder, final GenericProductModel model, final int position) {
            if(tv_no_item.getVisibility()== View.VISIBLE){
                tv_no_item.setVisibility(View.GONE);
            }
            viewHolder.cardname.setText(model.getCardname());
            viewHolder.cardprice.setText("₹ "+Float.toString(model.getCardprice()));
            Picasso.with(Tshirts.this).load(model.getCardimage()).into(viewHolder.cardimage);

            viewHolder.mView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent intent = new Intent(Tshirts.this,IndividualProduct.class);
                    intent.putExtra("product",getItem(position));
                    startActivity(intent);
                }
            });
        }
    };



    mRecyclerView.setAdapter(adapter);

}
 

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    recyclerView = new RecyclerView(this);
    LayoutUtil.setContentView(this, recyclerView);

    layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
    layoutManager1 = new GridLayoutManager(this, 2);
    layoutManager2 = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);
    recyclerView.setLayoutManager(layoutManager);

    data.addAll(DataManager.loadData(getBaseContext()));

    final CommonRcvAdapter<DemoModel> adapter = initAdapter();

    wrapper = new RcvAdapterWrapper(adapter, recyclerView.getLayoutManager());

    final Button header = new Button(this);
    header.setText("Header\n\n (click to add)");
    header.setLayoutParams(new RecyclerView.LayoutParams(RecyclerView.LayoutParams.MATCH_PARENT, 300));

    final Button footer = new Button(this);
    footer.setText("footer");

    wrapper.setHeaderView(header);
    wrapper.setFooterView(null);

    final Button empty = new Button(this);
    empty.setBackgroundColor(Color.RED);
    empty.setText("empty text");
    wrapper.setEmptyView(empty, recyclerView);

    recyclerView.setAdapter(wrapper);
    
    handItemClick();

    recyclerView.postDelayed(new Runnable() {
        @Override
        public void run() {
            data.reset(DataManager.loadData(getBaseContext(),10));
            wrapper.setFooterView(footer);
        }
    }, 1000);
}
 

@SuppressWarnings( "UnusedParameters" )
private void initInstance( View rootView ){
    int orientation = getResources().getConfiguration().orientation;
    int orientationLinear;
    int orientationGrid;
    int orientationStaggeredGrid;
    if( orientation == Configuration.ORIENTATION_PORTRAIT ){
        orientationLinear = LinearLayoutManager.VERTICAL;
        orientationGrid = GridLayoutManager.VERTICAL;
        orientationStaggeredGrid = StaggeredGridLayoutManager.VERTICAL;
    }else{
        orientationLinear = LinearLayoutManager.HORIZONTAL;
        orientationGrid = GridLayoutManager.HORIZONTAL;
        orientationStaggeredGrid = StaggeredGridLayoutManager.HORIZONTAL;
    }

    rvMargin = (RecyclerView) rootView.findViewById( R.id.rv_margin );
    int itemSpace = getSpace();
    int layout = getArguments().getInt( KEY_LAYOUT );
    if( layout == LINEAR ){
        rvMargin.removeItemDecoration( linearMargin );
        LinearLayoutManager layout1 = new LinearLayoutManager( getContext(), orientationLinear, false );
        rvMargin.setLayoutManager( layout1 );
        linearMargin = new LayoutMarginDecoration( itemSpace );
        linearMargin.setPadding( rvMargin, getMarginTop(), getMarginBottom(), getMarginLeft(), getMarginRight() );
        linearMargin.setOnClickLayoutMarginItemListener( onClickItem() );
        rvMargin.addItemDecoration( linearMargin );
    }else if( layout == GRID ){
        int gridSpan = 3;
        rvMargin.removeItemDecoration( gridMargin );
        rvMargin.setLayoutManager( new GridLayoutManager( getContext(), gridSpan, orientationGrid, false ) );
        gridMargin = new LayoutMarginDecoration( gridSpan, itemSpace );
        gridMargin.setPadding( rvMargin, getMarginTop(), getMarginBottom(), getMarginLeft(), getMarginRight() );
        gridMargin.setOnClickLayoutMarginItemListener( onClickItem() );
        rvMargin.addItemDecoration( gridMargin );
    }else if( layout == STAGGERED_GRID ){
        int stagSpan = 3;
        rvMargin.removeItemDecoration( stagMargin );
        rvMargin.setLayoutManager( new StaggeredGridLayoutManager( stagSpan, orientationStaggeredGrid ) );
        stagMargin = new LayoutMarginDecoration( stagSpan, itemSpace );
        stagMargin.setPadding( rvMargin, getMarginTop(), getMarginBottom(), getMarginLeft(), getMarginRight() );
        stagMargin.setOnClickLayoutMarginItemListener( onClickItem() );
        rvMargin.addItemDecoration( stagMargin );
    }
    rvMargin.setAdapter( new MarginAdapter( getContext() ) );
}
 

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_cart);

    Toolbar toolbar = findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    toolbar.setTitle("Cart");

    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
    getSupportActionBar().setDisplayShowHomeEnabled(true);


    //check Internet Connection
    new CheckInternetConnection(this).checkConnection();

    //retrieve session values and display on listviews
    getValues();

    //SharedPreference for Cart Value
    session = new UserSession(getApplicationContext());

    //validating session
    session.isLoggedIn();

    mRecyclerView = findViewById(R.id.recyclerview);
    tv_no_item = findViewById(R.id.tv_no_cards);
    activitycartlist = findViewById(R.id.activity_cart_list);
    emptycart = findViewById(R.id.empty_cart);
    cartcollect = new ArrayList<>();

    if (mRecyclerView != null) {
        //to enable optimization of recyclerview
        mRecyclerView.setHasFixedSize(true);
    }
    //using staggered grid pattern in recyclerview
    mLayoutManager = new StaggeredGridLayoutManager(1, StaggeredGridLayoutManager.VERTICAL);
    mRecyclerView.setLayoutManager(mLayoutManager);

    if(session.getCartValue()>0) {
        populateRecyclerView();
    }else if(session.getCartValue() == 0)  {
        tv_no_item.setVisibility(View.GONE);
        activitycartlist.setVisibility(View.GONE);
        emptycart.setVisibility(View.VISIBLE);
    }
}