Spannable RecyclerView像Snapchat-Discover

Question

我尝试使用TwoWayView库创建一个spannable recyclerView，如下图所示：https://github.com/lucasr/twoway-view

但我无法获得所需的视图，并且遗漏了空单元格。

        final SpannableGridLayoutManager.LayoutParams lp = (SpannableGridLayoutManager.LayoutParams) itemView.getLayoutParams();

        //final int span1 = (itemId == 0 || itemId == 3 ? 2 : 1);
        //final int span2 = (itemId == 0 ? 2 : (itemId == 3 ? 3 : 1));

        int span1 = 0; //h
        int span2 = 0; //w

        switch(itemId)
        {
        case 0:
            span1 = 2;
            span2 = 1;
            break;

        case 1:
            span1 = 2;
            span2 = 1;
            break;

        case 2:
            span1 = 2;
            span2 = 1;
            break;

        case 3:
            span1 = 3;
            span2 = 1;
            break;

        case 4:
            span1 = 3;
            span2 = 1;
            break;

        case 5:
            span1 = 4;
            span2 = 3;
            break;

        case 6:
            span1 = 2;
            span2 = 1;
            break;

        case 7:
            span1 = 2;
            span2 = 1;
            break;

        case 8:
            span1 = 2;
            span2 = 1;
            break;

        case 9:
            span1 = 2;
            span2 = 1;
            break;

        case 10:
            span1 = 4;
            span2 = 3;
            break;
        }

        final int colSpan = span2;
        final int rowSpan = span1;

        if (lp.rowSpan != rowSpan || lp.colSpan != colSpan) 
        {
            lp.rowSpan = rowSpan;
            lp.colSpan = colSpan;
            itemView.setLayoutParams(lp);
        }

XML：

<org.lucasr.twowayview.widget.TwoWayView
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/list"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    style="@style/TwoWayView"
    app:twowayview_layoutManager="ListLayoutManager"/>

价：

修改1 我能够通过在XML和以下跨度中将rowWidth更改为12来解决此问题：

        //PADDING-- left / top / right / bottom
    switch(itemId%11)
    {
    case 0:
        span1 = 4;
        span2 = 7;
        //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
        break;

    case 1:
        span1 = 4;
        span2 = 7;
        //holder.cont_frienddetail.setPadding(dpAsPixels2, dpAsPixels1, dpAsPixels2, dpAsPixels1);
        break;

    case 2:
        span1 = 4;
        span2 = 7;
        //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
        break;

    case 3:
        span1 = 4;
        span2 = 7;
        //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
        break;

    case 4:
        span1 = 8;
        span2 = 14;
        //holder.cont_frienddetail.setPadding(dpAsPixels2, dpAsPixels1, dpAsPixels0, dpAsPixels1);
        break;

    case 5:
        span1 = 4;
        span2 = 7;
        //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
        break;

    case 6:
        span1 = 6;
        span2 = 10;
        //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels2, dpAsPixels1);
        break;

    case 7:
        span1 = 6;
        span2 = 10;
        //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
        break;

    case 8:
        span1 = 8;
        span2 = 14;
        //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels2, dpAsPixels1);
        break;

    case 9:
        span1 = 4;
        span2 = 7;
        ///holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
        break;

    case 10:
        span1 = 4;
        span2 = 7;
        //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
        break;
    }

Answer 1

想象一下，拍摄示例图像并将每个单元格的垂直边界扩展到整个屏幕。如果你这样做，你会发现有六列。这就是解决问题的洞察力。

现在，您可以使用常规RecyclerView和GridLayoutManager执行此操作，而不必依赖于某人修复其GitHub库中的所有错误。

创建一个包含6列的GridLayoutManager，然后指定一个自定义SpanSizeLookup，使您的单元格的宽度不同。

在示例图像中，第一行中的三个单元格各占两列。第二行中的两个较大的单元每个跨越3列。左下方的单元格跨越4列。

所以现在你所要做的就是创建一个SpanSizeLookup来设置正确的宽度。

    // Create a grid layout with 6 columns
    // (least common multiple of 2 and 3)
    GridLayoutManager layoutManager = new GridLayoutManager(this, 6);

    layoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
        @Override
        public int getSpanSize(int position) {

            int widthClass = determineWidth(position) // TODO here you figure out what the cell width should be

            switch (widthClass) {
            case SMALL:
                return 2;   // fits 3 per row

            case MEDIUM:
                return 3;   // fits 2 per row

            case LARGE:     // fits 2 per row, one LARGE and one SMALL
                return 4;

            default:
                throw new IllegalStateException("don\'t know about widthClass " + widthClass);
            }
        }
    });

您可以查看我对类似问题here的原始答案。

Answer 2

我能够通过在XML和以下跨度中将rowWidth更改为12来解决此问题：

        //PADDING-- left / top / right / bottom
switch(itemId%11)
{
case 0:
    span1 = 4;
    span2 = 7;
    //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
    break;

case 1:
    span1 = 4;
    span2 = 7;
    //holder.cont_frienddetail.setPadding(dpAsPixels2, dpAsPixels1, dpAsPixels2, dpAsPixels1);
    break;

case 2:
    span1 = 4;
    span2 = 7;
    //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
    break;

case 3:
    span1 = 4;
    span2 = 7;
    //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
    break;

case 4:
    span1 = 8;
    span2 = 14;
    //holder.cont_frienddetail.setPadding(dpAsPixels2, dpAsPixels1, dpAsPixels0, dpAsPixels1);
    break;

case 5:
    span1 = 4;
    span2 = 7;
    //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
    break;

case 6:
    span1 = 6;
    span2 = 10;
    //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels2, dpAsPixels1);
    break;

case 7:
    span1 = 6;
    span2 = 10;
    //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
    break;

case 8:
    span1 = 8;
    span2 = 14;
    //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels2, dpAsPixels1);
    break;

case 9:
    span1 = 4;
    span2 = 7;
    ///holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
    break;

case 10:
    span1 = 4;
    span2 = 7;
    //holder.cont_frienddetail.setPadding(dpAsPixels0, dpAsPixels1, dpAsPixels0, dpAsPixels1);
    break;
}

Answer 3

请参阅此链接The link you getting help

Full source code

<强>代码。

  

MainActivity.java

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;


public class MainActivity extends AppCompatActivity {

    public static final String TYPE_VERTICAL_LIST= "Vertical List";
    public static final String TYPE_HORIZONTAL_LIST= "Horizontal List";
    public static final String TYPE_GRID_VIEW = "Grid View";
    public static final String TYPE_HORIZONTAL_GRID_VIEW_STAGGERED = "HorizontalStaggeredGridView";
    public static final String TYPE_VERTICAL_GRID_VIEW_STAGGERED = "VerticalStaggeredGridView";
    public static final String TYPE = "TYPE";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    attachFragment(TYPE_VERTICAL_LIST);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.menu_main, menu);
    /** Return false so that we can capture {@link PlaceholderFragment#onOptionsItemSelected(android.view.MenuItem)} events in {@link PlaceholderFragment} Fragment*/
    return false;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

    switch (item.getItemId()){
        case R.id.action_vertical_list:
        attachFragment(TYPE_VERTICAL_LIST);
        break;
        case R.id.action_horizontal_list:
        attachFragment(TYPE_HORIZONTAL_LIST);
        break;
        case R.id.action_grid_view:
        attachFragment(TYPE_GRID_VIEW);
        break;
        case R.id.action_vertical_grid_view_staggered:
        attachFragment(TYPE_VERTICAL_GRID_VIEW_STAGGERED);
        break;
        case R.id.action_horizontal_grid_view_staggered:
        attachFragment(TYPE_HORIZONTAL_GRID_VIEW_STAGGERED);
        break;
    }

    return super.onOptionsItemSelected(item);
    }


    /** Attach placeholder fragment here and show different kind of RecyclerView flavours eg List or grid based on user selection in the options menu.*/
    private void attachFragment(String type){
    Bundle bundle = new Bundle();
    bundle.putString(TYPE, type);
    PlaceholderFragment placeholderFragment = new PlaceholderFragment();
    placeholderFragment.setArguments(bundle);
    getSupportFragmentManager().beginTransaction().replace(R.id.container, placeholderFragment).commit();
    }
    }

  

PlaceholderFragment.java

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;


public class PlaceholderFragment extends Fragment {

    private static final String TAG = "PlaceholderFragment";
    /*Number of columns in the grid view*/
    private static final int NUM_OF_COLUMNS = 2;
    /*Total number of items in the RecyclerView*/
    private static final int NUM_OF_ITEMS = 100;
    private ArrayList<DataModel> mDataModels;
    private RecyclerView recyclerView;
    private RecyclerViewAdapter recyclerViewAdapter;
    private int addItemCount = 0;


    public PlaceholderFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
        //Must be set in order to capture menu item click events. If you don't set it, it will not show the menu items set in the Activity holding this fragment.
        setHasOptionsMenu(true);
        View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        recyclerView = (RecyclerView)rootView.findViewById(R.id.recyclerview);


        RecyclerView.LayoutManager layoutManager = null;
        String type = getArguments().getString(MainActivity.TYPE);
        if( type.equals(MainActivity.TYPE_VERTICAL_LIST)){
            /*LinearLayoutManager to show a vertical list view*/
            layoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false);
        }else if(type.equals(MainActivity.TYPE_HORIZONTAL_LIST)){
            /*LinearLayoutManager to show a horizontal list view*/
            layoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.HORIZONTAL, false);
        }else if(type.equals(MainActivity.TYPE_GRID_VIEW)){
             /*LinearLayoutManager to show a grid view. We can specify number of columns in the grid.*/
            layoutManager = new GridLayoutManager(getActivity(), NUM_OF_COLUMNS);

        }else if(type.equals(MainActivity.TYPE_HORIZONTAL_GRID_VIEW_STAGGERED)){
             /*LinearLayoutManager to show a staggered grid view. We can specify number of columns in the grid.*/
            //spanCount:   If orientation is vertical, spanCount is number of columns. If orientation is horizontal, spanCount is number of rows.
            //orientation: StaggeredGridLayoutManager.HORIZONTAL or StaggeredGridLayoutManager.HORIZONTAL
            layoutManager = new StaggeredGridLayoutManager(3/*span count*/, StaggeredGridLayoutManager.HORIZONTAL/* orientation*/);

        }else if(type.equals(MainActivity.TYPE_VERTICAL_GRID_VIEW_STAGGERED)){
             /*LinearLayoutManager to show a staggered grid view. We can specify number of columns in the grid.*/
            //spanCount:   If orientation is vertical, spanCount is number of columns. If orientation is horizontal, spanCount is number of rows.
            //orientation: StaggeredGridLayoutManager.HORIZONTAL or StaggeredGridLayoutManager.HORIZONTAL
            layoutManager = new StaggeredGridLayoutManager(2/*span count*/, StaggeredGridLayoutManager.VERTICAL/* orientation*/);

        }

        recyclerView.setLayoutManager(layoutManager);
        mDataModels = getDataModelList();
        recyclerViewAdapter = new RecyclerViewAdapter(mDataModels, type);

        /*Third party ItemDecoration found from https://gist.github.com/alexfu/0f464fc3742f134ccd1e*/
        RecyclerView.ItemDecoration verticalDivider  = new DividerItemDecoration(getActivity(), DividerItemDecoration.VERTICAL_LIST);
        RecyclerView.ItemDecoration horizontalDivider = new DividerItemDecoration(getActivity(), DividerItemDecoration.HORIZONTAL_LIST);
        recyclerView.addItemDecoration(horizontalDivider);
        recyclerView.addItemDecoration(verticalDivider);

        // this is the default;
        // this call is actually only necessary with custom ItemAnimators
        recyclerView.setItemAnimator(new DefaultItemAnimator());

        recyclerView.setAdapter(recyclerViewAdapter);
        return rootView;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        switch (item.getItemId()){
            case R.id.action_add_item:
                addItem();
                break;
            case R.id.action_delete_item:
                deleteItem();
                break;

        }

        return super.onOptionsItemSelected(item);
    }

    /** Creates and returns the data items to be shown in the Recycler View*/
    private ArrayList<DataModel> getDataModelList(){
        ArrayList<DataModel> dataModels = new ArrayList<>();

        for (int i = 0; i < NUM_OF_ITEMS; i++) {
            dataModels.add(new DataModel("Title:"+i));
        }

        return dataModels;
    }


    /** Adds a single item in the existing list*/
    private final void addItem(){
        //Adding item at top second position(i.e. at index 1).
        mDataModels.set(1, new DataModel("Added Item "+String.valueOf(++addItemCount)));
        //See for similar methods to know more item insertion options
        recyclerViewAdapter.notifyItemInserted(1);
    }

    /** Deletes a single item from the existing list*/
    private void deleteItem(){
        //Removing top item
        mDataModels.remove(0);
        //See for similar methods to know more item removing options
        recyclerViewAdapter.notifyItemRemoved(0);
    }

}

  

ListItemViewHolder.java

public class ListItemViewHolder extends ViewHolder {

ImageView imgView;
TextView title;

public ListItemViewHolder(View itemView) {
    super(itemView);
    title = (TextView) itemView.findViewById(R.id.textview_title);
    imgView = (ImageView) itemView.findViewById(R.id.imageview_icon);
 }
 }

  

DividerItemDecoration.java

 import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;


public class DividerItemDecoration extends RecyclerView.ItemDecoration {

    private static final int[] ATTRS = new int[]{
            android.R.attr.listDivider
    };

    public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

    public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;

    private Drawable mDivider;

    private int mOrientation;

    public DividerItemDecoration(Context context, int orientation) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
        setOrientation(orientation);
    }

    public void setOrientation(int orientation) {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
            throw new IllegalArgumentException("invalid orientation");
        }
        mOrientation = orientation;
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {
            drawVertical(c, parent);
        } else {
            drawHorizontal(c, parent);
        }
    }

    public void drawVertical(Canvas c, RecyclerView parent) {
        final int left = parent.getPaddingLeft();
        final int right = parent.getWidth() - parent.getPaddingRight();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    public void drawHorizontal(Canvas c, RecyclerView parent) {
        final int top = parent.getPaddingTop();
        final int bottom = parent.getHeight() - parent.getPaddingBottom();

        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int left = child.getRight() + params.rightMargin;
            final int right = left + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    @Override
    public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        }
    }
}

  

RecyclerViewAdapter.java

import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;

public class RecyclerViewAdapter extends RecyclerView.Adapter<ListItemViewHolder> {


    private ArrayList<DataModel> mDataModels;
    private String mType;

    public RecyclerViewAdapter(ArrayList<DataModel> mDataModels, String mType) {
        this.mDataModels = mDataModels;
        this.mType = mType;
    }


    @Override
    public ListItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_recycler_view, parent, false);
        return new ListItemViewHolder(itemView);
    }


    @Override
    public void onBindViewHolder(ListItemViewHolder holder, int position) {
        DataModel model = mDataModels.get(position);
        holder.title.setText(model.getTitle());
        if(position % 2 == 0){
            if(mType.equals(MainActivity.TYPE_VERTICAL_GRID_VIEW_STAGGERED)){
                holder.imgView.setImageResource(R.drawable.lollipop);
            }else{
                holder.imgView.setImageResource(R.drawable.lollipop_h1);
            }

        }else if(position % 3 == 0){
            if(mType.equals(MainActivity.TYPE_VERTICAL_GRID_VIEW_STAGGERED)){
                holder.imgView.setImageResource(R.drawable.lollipop1);
            }else{
                holder.imgView.setImageResource(R.drawable.lollipop_h2);
            }
        }else{
            if(mType.equals(MainActivity.TYPE_VERTICAL_GRID_VIEW_STAGGERED)){
                holder.imgView.setImageResource(R.drawable.lollipop2);
            }else{

                holder.imgView.setImageResource(R.drawable.lollipop_h3);
            }
        }
    }


    @Override
    public int getItemCount() {
        return mDataModels.size();
    }
}

  

DataModel.java

public class DataModel {

    private String title;

    public DataModel(String title) {
        this.title = title;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }
}

  

activity_main.xml中

  <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    tools:ignore="MergeRootFrame" />

  

fragment_main.xml       

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:context=".MainActivity"
        tools:listitem="@layout/item_recycler_view"
        />

</RelativeLayout>

  

item_recycler_view.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center_vertical"
    android:padding="8dp"
    android:background="@android:color/holo_green_dark">

    <ImageView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/imageview_icon"
        android:src="@drawable/lollipop"
        android:scaleType="centerCrop"/>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="New Text"
        android:id="@+id/textview_title"
        android:background="@android:color/darker_gray"/>
</LinearLayout>