RecyclerView使用秘籍手册

以前一直使用ListView，普通需求使用算是简单，现在使用RecyckerView能够更强大的简化使用，来满足更多需求。

纵向滑动横向滑动（线性、格子、瀑布流）

//        ListView形式上下滑动：
         LinearLayoutManager manager = new LinearLayoutManager(this);
        manager.setOrientation(LinearLayoutManager.VERTICAL);

//        左右滑动：
        LinearLayoutManager manager = new LinearLayoutManager(this);
        manager.setOrientation(LinearLayoutManager.HORIZONTAL);

//        Grid形式上下滑动：
        GridLayoutManager manager = new GridLayoutManager(this,4);
//        Grid形式左右滑动：
        GridLayoutManager manager = new GridLayoutManager(this, 4);
        manager.setOrientation(GridLayoutManager.HORIZONTAL);

//        瀑布流形式上下滑动：
        StaggeredGridLayoutManager manager = new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.VERTICAL);
//        瀑布流形式左右滑动：
        StaggeredGridLayoutManager manager = new StaggeredGridLayoutManager(4, StaggeredGridLayoutManager.HORIZONTAL);

2、Adapter 适配器(触发响应事件)（RecyclerView动画展示）

public class RecyclerView1Adapter extends RecyclerView.Adapter<RecyclerView1Adapter.MyViewHolder> {

    private List<String> mData;
    private Context mContext;
    private boolean flag;
    private int mLastPosition;


    public RecyclerView1Adapter(List<String> mData, Context mContext) {
        this.mData = mData;
        this.mContext = mContext;
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recy_view_item_tv,parent,false);
        final MyViewHolder holder = new MyViewHolder(view);
        Log.e("chenxh","onCreateViewHolder");
        holder.addBtn.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                new AlertDialog.Builder(v.getContext())
                        .setTitle("确认删除吗")
                        .setNegativeButton("取消",null)
                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                if (flag == true){
                                    removeData(holder.getAdapterPosition());
                                    flag=false;
                                }else{
                                    addData(holder.getAdapterPosition());
                                    flag=true;
                                }
                            }
                        }).show();
                return false;
            }
        });
        return holder;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, final int position) {
        holder.tv1.setText(mData.get(position));
        Log.e("chenxh","onBindViewHolder"+position);
        holder.tv1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(mContext, mData.get(position), Toast.LENGTH_SHORT).show();
            }
        });
        //动画核心
        if (holder.getAdapterPosition() > mLastPosition) {
            ObjectAnimator scaleX = ObjectAnimator.ofFloat(holder.itemView, "scaleX", 0.5f, 1f);
            scaleX.start();
            mLastPosition = holder.getLayoutPosition();
        }
    }


    /**
     * getItemViewType()
     * 多布局 核心方法  getItemViewType
     * 1、onCreateViewHolder中判断  ==      viewType 进行viewHolder的填充
     * 2、onBindViewHolder中判断 instanceof  viewHolder
     * @param position
     * @return viewType(){Integer}
     */
    @Override
    public int getItemViewType(int position) {

        return 0;

    }

    @Override
    public int getItemCount() {

        return mData.size();
    }

    class MyViewHolder extends RecyclerView.ViewHolder{

        Button addBtn,removeBtn;
        TextView tv1;

        public MyViewHolder(View itemView) {
            super(itemView);
            tv1 = (TextView) itemView.findViewById(R.id.recy_view_item_tv1);
            addBtn = (Button) itemView.findViewById(R.id.recy_view_item_btn1);
        }
    }
//    添加数据
    public void addData(int position) {
        mData.add(position,"addData"+position);
        notifyItemInserted(position);
    }
//    删除数据
    public void removeData(int position) {
        mData.remove(position);
        notifyItemRemoved(position);
    }

}

//添加默认的动画
mRecyclerView.setItemAnimator(new DefaultItemAnimator());

3、刷新数据

  runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                     //数据更新
                        initmData();
            //Adapter更新RecyclerView  
                         adapter.notifyDataSetChanged();

                    }
                });

4、添加线性的分割线

mRecyclerView.addItemDecoration(new MyDividerItemDecoration(this, MyDividerItemDecoration.VERTICAL_LIST));

分割线类：

public class MyDividerItemDecoration 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 int mOrientation;
    private Drawable mDivider;
    private int mDividerHeight = 2; //默认是2px
    private Paint mPaint;
    //绘制默认分割线
    public MyDividerItemDecoration(Context context, int orientation) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        //系统属性中获取
        a.recycle();
        setOrientation(orientation);
    }
    /**
     * 自定义分割线
     *
     * @param context
     * @param orientation 列表方向
     * @param drawableId  分割线图片
     */
    public MyDividerItemDecoration(Context context, int orientation, int drawableId) {
        this(context, orientation);
        mDivider = ContextCompat.getDrawable(context, drawableId);
        mDividerHeight = mDivider.getIntrinsicHeight();
    }
    /**
     * 自定义分割线
     *
     * @param context
     * @param orientation   列表方向
     * @param dividerHeight 分割线高度
     * @param dividerColor  分割线颜色
     */
    public MyDividerItemDecoration(Context context, int orientation, int dividerHeight, int dividerColor) {
        this(context, orientation);
        mDividerHeight = dividerHeight;
        mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
        mPaint.setColor(dividerColor);
        mPaint.setStyle(Paint.Style.FILL);
    }

    private void setOrientation(int orientation) {
        if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {
            throw new IllegalArgumentException("invalid orientaion");
        }
        mOrientation = orientation;
    }
    @Override
    //在RecyclerView的onDraw中执行
    public void onDraw(Canvas c, RecyclerView parent) {
        if (mOrientation == VERTICAL_LIST) {
            drawVertical(c, parent);
        } else {
            drawHorizontal(c, parent);
        }
    }
    private 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-1; 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);
        }
    }
    private 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-1; i++) {
            final View child = parent.getChildAt(i);
            RecyclerView v = new RecyclerView(parent.getContext());
            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);
        }
    }
    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        if (mOrientation == VERTICAL_LIST) {
            outRect.set(0, 0, 0, mDividerHeight);
        } else {
            outRect.set(0, 0, mDividerHeight, 0);
        }
    }
}

5、多布局三步走
①：Adapter中重写getItemViewType方法

@Override
public int getItemViewType(int position) {    
    if (mNewsBeanList.get(position).getThumbnail_pic_s03() == null) {        
        return IMAGE_ONLY_ONE;
    } else {        
        return IMAGE_TWOORTHREE;
    }
}

②：在onCreateViewHolder方法中第二个参数对应的就是上面方法返回的值，我们根据值的不同，填充不同的布局

@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {    
    if (viewType == IMAGE_TWOORTHREE) {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.news_imagethree_item, viewGroup, false);
        ImageThreeViewHolder viewHolder = new ImageThreeViewHolder(view);        
        return viewHolder;
    } else {
        View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.news_imageonly_item, viewGroup, false);
        ImageOnlyOneViewHolder viewHolder = new ImageOnlyOneViewHolder(view);        
        return viewHolder;
    }
}

③：不同的布局需要不同的ViewHolder，在onBindViewHolder方法中的第一个参数对应不同的viewholder，我们通过判断，来进行每个元素的写入

public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {    

    if (viewHolder instanceof ImageThreeViewHolder) {
        ((ImageThreeViewHolder) viewHolder).mTv_title.setText(mNewsBeanList.get(position).getTitle());

    }

}

6、添加Grid的分割线

mRecyclerView.addItemDecoration(new DividerGridItemDecoration(this));

public class DividerGridItemDecoration extends RecyclerView.ItemDecoration{
    private static final int[] ATTRS = new int[] { android.R.attr.listDivider };
    private Drawable mDivider;
    public DividerGridItemDecoration(Context context){
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    @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
                    + mDivider.getIntrinsicWidth();
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + mDivider.getIntrinsicHeight();
            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 + mDivider.getIntrinsicWidth();

            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, int itemPosition,
                               RecyclerView parent)
    {
        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, mDivider.getIntrinsicWidth(), 0);
        } else if (isLastColum(parent, itemPosition, spanCount, childCount))// 如果是最后一列，则不需要绘制右边
        {
            outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
        } else
        {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(),
                    mDivider.getIntrinsicHeight());
        }
    }
}

RecyclerView使用秘籍手册

猜你喜欢