Android 开发之 RecyclerView 拖拽 + 固定首个

仿腾讯视频中全部频道界面，首个精选长按不能拖动，其余的可以拖动。

效果图

[外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-BM9PvvMM-1575528781211)(https://img-my.csdn.net/uploads/201709/08/1504861595_9196.gif-thumb.jpg)]

1、添加依赖

dependencies {
    compile 'com.android.support:recyclerview-v7:25.2.0'
}

2、布局

activity_grid_view.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.gyq.recyclerviewtest.GridViewActivity">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_grid"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:clipChildren="false"
        android:clipToPadding="false"/>

FrameLayout>

item_grid_view.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@android:color/white"
    android:padding="10dp"
    android:orientation="vertical">

    <ImageView
        android:id="@+id/img_item"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        app:srcCompat="@drawable/ic_fruit_icons_01"/>

    <TextView
        android:id="@+id/tv_item"
        android:layout_marginTop="10dp"
        style="@style/TextAppearance.AppCompat.Button"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:text="item"/>

LinearLayout>

3、逻辑代码

1，GridViewActivity.java

package com.gyq.recyclerviewtest;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;
import android.view.MenuItem;
import android.widget.Toast;

import com.gyq.recyclerviewtest.adapter.RecyAdapter;
import com.gyq.recyclerviewtest.bean.DataManager;
import com.gyq.recyclerviewtest.recyevent.OnRecyclerItemClickListener;
import com.gyq.recyclerviewtest.recyevent.RecyItemTouchHelperCallback;
import com.gyq.recyclerviewtest.recymbelish.DividerGridItemDecoration;

import java.util.ArrayList;
import java.util.List;

public class GridViewActivity extends AppCompatActivity {
    RecyclerView mRecyclerView;
    List<String> mStringList;
    RecyAdapter mRecyAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_grid_view);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        mRecyclerView = (RecyclerView) findViewById(R.id.recycler_grid);
        initRecy();
    }

    private void initRecy() {
        if (mStringList == null) {
            mStringList = new ArrayList<>();
        }
        mStringList.addAll(DataManager.getData(9));
        mRecyAdapter = new RecyAdapter(R.layout.item_grid_view, mStringList, true);

        mRecyclerView.setLayoutManager(new GridLayoutManager(this, 4));
        mRecyclerView.addItemDecoration(new DividerGridItemDecoration(this));
        mRecyclerView.setHasFixedSize(true);

        RecyItemTouchHelperCallback itemTouchHelperCallback = new RecyItemTouchHelperCallback(mRecyAdapter, false, true);
        final ItemTouchHelper itemTouchHelper = new ItemTouchHelper(itemTouchHelperCallback);
        itemTouchHelper.attachToRecyclerView(mRecyclerView);

        mRecyclerView.addOnItemTouchListener(new OnRecyclerItemClickListener(mRecyclerView) {
            @Override
            public void onItemClick(RecyclerView.ViewHolder viewHolder) {
                RecyAdapter.ViewHolder viewHolder1 = (RecyAdapter.ViewHolder) viewHolder;
                String tvString = viewHolder1.mTextView.getText().toString();
                Toast.makeText(GridViewActivity.this, "点击了..." + tvString, Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onLongClick(RecyclerView.ViewHolder viewHolder) {
                Toast.makeText(GridViewActivity.this, "" + "长按拖动...", Toast.LENGTH_SHORT).show();
                if (viewHolder.getLayoutPosition() != 0) {
                    itemTouchHelper.startDrag(viewHolder);
                }
            }
        });
        mRecyclerView.setAdapter(mRecyAdapter);
    }

    
}

适配器

package com.gyq.recyclerviewtest.adapter;

import android.graphics.Color;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import com.gyq.recyclerviewtest.R;

import java.util.Arrays;
import java.util.List;

/**
 * Created by gyq on 2017/9/8 09:59
 */
public class RecyAdapter extends RecyclerView.Adapter<RecyAdapter.ViewHolder> {
    private int item_layout;
    private List<String> mDataList;
    private List<Integer> mInts;
    private boolean isFirstSpecial;

    public RecyAdapter(int item_layout, List<String> dataList) {
        this.item_layout = item_layout;
        mDataList = dataList;
        mInts = Arrays.asList(R.drawable.dsj, R.drawable.dy,
                R.drawable.yy, R.drawable.wzry,
                R.drawable.nnhk, R.drawable.zy,
                R.drawable.ty, R.drawable.se, R.drawable.dm);
    }

    public RecyAdapter(int item_layout, List<String> dataList, boolean isFirstSpecial) {
        this(item_layout, dataList);
        this.isFirstSpecial = isFirstSpecial;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(item_layout, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        String string = mDataList.get(position);
        if (isFirstSpecial && position == 0) {
            holder.itemView.setBackgroundColor(Color.LTGRAY);
            holder.mTextView.setText("精选");
            holder.mImageView.setImageResource(R.drawable.jx);
        } else {
            holder.itemView.setBackgroundColor(Color.WHITE);
            holder.mTextView.setText(string);
            holder.mImageView.setImageResource(mInts.get(position % mInts.size()));
        }
    }

    @Override
    public int getItemCount() {
        return mDataList == null ? 0 : mDataList.size();
    }

    public List<String> getDataList() {
        return mDataList;
    }

    public class ViewHolder extends RecyclerView.ViewHolder {
        public TextView mTextView;
        ImageView mImageView;

        ViewHolder(View itemView) {
            super(itemView);
            mTextView = (TextView) itemView.findViewById(R.id.tv_item);
            mImageView = (ImageView) itemView.findViewById(R.id.img_item);
        }
    }
}

recyclerView 的分割线

package com.gyq.recyclerviewtest.recymbelish;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Rect;
import android.graphics.drawable.ColorDrawable;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.View;

/**
 * Created by gyq on 2017/9/8 10:03
 */
public class DividerGridItemDecoration extends RecyclerView.ItemDecoration {
    private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
    private Drawable mDivider;
    private int lineWidth = 1;

    public DividerGridItemDecoration(Context context) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    public DividerGridItemDecoration(int color) {
        mDivider = new ColorDrawable(color);
    }

    public DividerGridItemDecoration() {
        this(Color.parseColor("#cccccc"));
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
        drawHorizontal(c, parent);
        drawVertical(c, parent);
    }

    private int getSpanCount(RecyclerView parent) {
        // 列数
        int spanCount = -1;
        RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager) {

            spanCount = ((GridLayoutManager) layoutManager).getSpanCount();
        } else if (layoutManager instanceof StaggeredGridLayoutManager) {
            spanCount = ((StaggeredGridLayoutManager) layoutManager)
                    .getSpanCount();
        }
        return spanCount;
    }

    public void drawHorizontal(Canvas c, RecyclerView parent) {
        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.getLeft() - params.leftMargin;
            final int right = child.getRight() + params.rightMargin
                    + lineWidth;
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + lineWidth;
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    public void drawVertical(Canvas c, RecyclerView parent) {
        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.getTop() - params.topMargin;
            final int bottom = child.getBottom() + params.bottomMargin;
            final int left = child.getRight() + params.rightMargin;
            final int right = left + lineWidth;

            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    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
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        boolean b = state.willRunPredictiveAnimations();
        int itemPosition = ((RecyclerView.LayoutParams) view.getLayoutParams()).getViewLayoutPosition();
        int spanCount = getSpanCount(parent);
        int childCount = parent.getAdapter().getItemCount();
//        if (isLastRaw(parent, itemPosition, spanCount, childCount))// 如果是最后一行，则不需要绘制底部
//        {
//            outRect.set(0, 0, lineWidth, 0);
//        }
//        else if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最后一列，则不需要绘制右边
//        {
            if (b){
                outRect.set(0, 0, lineWidth, lineWidth);
            }else {
//                outRect.set(0, 0, 0, lineWidth);
            }
//        }
//        else {
        outRect.set(0, 0, lineWidth, lineWidth);
//        }
    }
}

点击事件
OnRecyclerItemClickListener.java

package com.gyq.recyclerviewtest.recyevent;

import android.support.v4.view.GestureDetectorCompat;
import android.support.v7.widget.RecyclerView;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;

/**
 * Created by gyq on 2017/9/8 10:08
 */
public abstract class OnRecyclerItemClickListener implements RecyclerView.OnItemTouchListener{
    private GestureDetectorCompat mGestureDetectorCompat;
    private RecyclerView mRecyclerView;

    public OnRecyclerItemClickListener(RecyclerView recyclerView) {
        mRecyclerView = recyclerView;
        mGestureDetectorCompat = new GestureDetectorCompat(mRecyclerView.getContext(),
                new ItemTouchHelperGestureListener());
    }

    @Override
    public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) {
        mGestureDetectorCompat.onTouchEvent(e);
        return false;
    }

    @Override
    public void onTouchEvent(RecyclerView rv, MotionEvent e) {
        mGestureDetectorCompat.onTouchEvent(e);
    }

    @Override
    public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

    }

    public abstract void onItemClick(RecyclerView.ViewHolder viewHolder);
    public abstract void onLongClick(RecyclerView.ViewHolder viewHolder);

    private class ItemTouchHelperGestureListener extends GestureDetector.SimpleOnGestureListener{
        @Override
        public boolean onSingleTapUp(MotionEvent e) {
            View childViewUnder = mRecyclerView.findChildViewUnder(e.getX(), e.getY());
            if (childViewUnder != null) {
                RecyclerView.ViewHolder childViewHolder = mRecyclerView.getChildViewHolder(childViewUnder);
                onItemClick(childViewHolder);
            }
            return true;
        }

        @Override
        public void onLongPress(MotionEvent e) {
            View childViewUnder = mRecyclerView.findChildViewUnder(e.getX(), e.getY());
            if (childViewUnder != null) {
                RecyclerView.ViewHolder childViewHolder = mRecyclerView.getChildViewHolder(childViewUnder);
                onLongClick(childViewHolder);
            }
        }
    }
}

RecyItemTouchHelperCallback.java

package com.gyq.recyclerviewtest.recyevent;

import android.graphics.Color;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.helper.ItemTouchHelper;

import com.gyq.recyclerviewtest.adapter.RecyAdapter;

import java.util.Collections;

/**
 * Created by gyq on 2017/9/8 10:08
 */
public class RecyItemTouchHelperCallback extends ItemTouchHelper.Callback {
    RecyclerView.Adapter mAdapter;
    boolean isSwipeEnable;
    boolean isFirstDragUnable;

    public RecyItemTouchHelperCallback(RecyclerView.Adapter adapter) {
        mAdapter = adapter;
        isSwipeEnable = true;
        isFirstDragUnable = false;
    }

    public RecyItemTouchHelperCallback(RecyclerView.Adapter adapter, boolean isSwipeEnable, boolean isFirstDragUnable) {
        mAdapter = adapter;
        this.isSwipeEnable = isSwipeEnable;
        this.isFirstDragUnable = isFirstDragUnable;
    }

    @Override
    public int getMovementFlags(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        if (recyclerView.getLayoutManager() instanceof GridLayoutManager) {
            int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN |
                    ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT;
            int swipeFlags = 0;
            return makeMovementFlags(dragFlags, swipeFlags);
        } else {
            int dragFlags = ItemTouchHelper.UP | ItemTouchHelper.DOWN;
            int swipeFlags = ItemTouchHelper.START | ItemTouchHelper.END;
            return makeMovementFlags(dragFlags, swipeFlags);
        }
    }

    @Override
    public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {
        int fromPosition = viewHolder.getAdapterPosition();
        int toPosition = target.getAdapterPosition();
        if (isFirstDragUnable && toPosition == 0) {
            return false;
        }
        if (fromPosition < toPosition) {
            for (int i = fromPosition; i < toPosition; i++) {
                Collections.swap(((RecyAdapter) mAdapter).getDataList(), i, i + 1);
            }
        } else {
            for (int i = fromPosition; i > toPosition; i--) {
                Collections.swap(((RecyAdapter) mAdapter).getDataList(), i, i - 1);
            }
        }
        mAdapter.notifyItemMoved(fromPosition, toPosition);
        return true;
    }

    @Override
    public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {
        int adapterPosition = viewHolder.getAdapterPosition();
        mAdapter.notifyItemRemoved(adapterPosition);
        ((RecyAdapter) mAdapter).getDataList().remove(adapterPosition);
    }

    @Override
    public void onSelectedChanged(RecyclerView.ViewHolder viewHolder, int actionState) {
        if (actionState != ItemTouchHelper.ACTION_STATE_IDLE) {
            viewHolder.itemView.setBackgroundColor(Color.LTGRAY);
        }
        super.onSelectedChanged(viewHolder, actionState);
    }

    @Override
    public void clearView(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {
        super.clearView(recyclerView, viewHolder);
        viewHolder.itemView.setBackgroundColor(Color.WHITE);
    }

    @Override
    public boolean isLongPressDragEnabled() {
        return !isFirstDragUnable;
    }

    @Override
    public boolean isItemViewSwipeEnabled() {
        return isSwipeEnable;
    }
}

数据
DataManager.java

package com.gyq.recyclerviewtest.bean;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * Created by gyq on 2017/9/8 10:02
 */
public class DataManager {
    private static List<String> sStringList = Arrays.asList("电视剧", "电影", "音乐", "王者荣耀",
            "那年花开", "综艺", "体育", "少儿", "动漫");

    public static final List<String> getData(int number) {
        List<String> stringList = new ArrayList<>();
        for (int i = 0; i < number; i++) {
            stringList.add(sStringList.get(i % sStringList.size()));
        }
        return stringList;
    }
}

OK，结束啦！