Android开发-RecyclerView线性布局，水平布局，网格布局

RecyclerView

RecyclerView能够灵活的实现大数据集的展示，视图的复用管理比ListView更好，能够显示列表、网格、瀑布流等形式，且不同的ViewHolder能够实现item多元化的功能。
但是使用起来会稍微麻烦一点，并且没有类似ListView的onItemClickListener监听事件，需要开发者自己实现。

1.线性布局

线性布局效果图

RecyclerView

activity_linear_recycler_view.xml

RecyclerViewItem

Activity

LinearRecyclerViewActivity

public class LinearRecyclerViewActivity extends AppCompatActivity {

    private RecyclerView mRvMain;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_linear_recycler_view);
        mRvMain = findViewById(R.id.rv_main);
        mRvMain.setLayoutManager(new LinearLayoutManager(LinearRecyclerViewActivity.this));
        mRvMain.addItemDecoration(new MyDecoration());
        mRvMain.setAdapter(new LinearAdapter(LinearRecyclerViewActivity.this, new LinearAdapter.OnItemClickListener() {
            @Override
            public void onClick(int pos) {
                Toast.makeText(LinearRecyclerViewActivity.this, "回调点击：" + pos, Toast.LENGTH_SHORT).show();
            }
        }));
    }

    class MyDecoration extends RecyclerView.ItemDecoration {

        @Override
        public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
            super.getItemOffsets(outRect, view, parent, state);
            outRect.set(0,0,0,getResources().getDimensionPixelOffset(R.dimen.dividerHeight));
        }
    }
}

Adapter

LinearAdapter

public class LinearAdapter extends RecyclerView.Adapter {

    private Context mContext;
    private OnItemClickListener mListener;

    public LinearAdapter(Context context, OnItemClickListener listener) {

        mContext = context;
        mListener = listener;
    }

    @NonNull
    @Override
    public LinearAdapter.LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new LinearViewHolder(LayoutInflater.from(mContext).inflate(R.layout.layout_linear_item, parent, false));
    }

    @Override
    public void onBindViewHolder(@NonNull LinearAdapter.LinearViewHolder holder, final int position) {
        holder.textView.setText("Hello World!");
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mListener.onClick(position);
//                Toast.makeText(mContext, "点击：" + position, Toast.LENGTH_SHORT).show();
            }
        });
    }

    @Override
    public int getItemCount() {
        return 30;
    }

    class LinearViewHolder extends RecyclerView.ViewHolder {
        private TextView textView;
        public LinearViewHolder(@NonNull View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.tv_title);
        }
    }

    public interface OnItemClickListener {
        void onClick(int pos);
    }
}

2.水平布局

水平布局效果图

RecyclerView

RecyclerViewItem

HorAdapter

public class HorAdapter extends RecyclerView.Adapter {

    private Context mContext;
    private OnItemClickListener mListener;

    public HorAdapter(Context context, OnItemClickListener listener) {

        mContext = context;
        mListener = listener;
    }

    @NonNull
    @Override
    public HorAdapter.LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new LinearViewHolder(LayoutInflater.from(mContext).inflate(R.layout.layout_hor_item, parent, false));
    }

    @Override
    public void onBindViewHolder(@NonNull HorAdapter.LinearViewHolder holder, final int position) {
        holder.textView.setText("Hello!");
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mListener.onClick(position);
//                Toast.makeText(mContext, "点击：" + position, Toast.LENGTH_SHORT).show();
            }
        });
    }

    @Override
    public int getItemCount() {
        return 30;
    }

    class LinearViewHolder extends RecyclerView.ViewHolder {
        private TextView textView;
        public LinearViewHolder(@NonNull View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.tv_title);
        }
    }

    public interface OnItemClickListener {
        void onClick(int pos);
    }
}

HorRecyclerViewActivity

public class HorRecyclerViewActivity extends AppCompatActivity {

    private RecyclerView mRvHor;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_hor_recycler_view);
        mRvHor = findViewById(R.id.rv_hor);

        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(HorRecyclerViewActivity.this);
        linearLayoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
        mRvHor.setLayoutManager(linearLayoutManager);
        mRvHor.addItemDecoration(new MyDecoration());
        mRvHor.setAdapter(new HorAdapter(HorRecyclerViewActivity.this, new HorAdapter.OnItemClickListener() {
            @Override
            public void onClick(int pos) {
                Toast.makeText(HorRecyclerViewActivity.this, "Click:"+pos, Toast.LENGTH_SHORT).show();
            }
        }));
    }

    class MyDecoration extends RecyclerView.ItemDecoration {
        @Override
        public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
            super.getItemOffsets(outRect, view, parent, state);
            outRect.set(0,0,getResources().getDimensionPixelOffset(R.dimen.dividerHeight),0);
        }
    }
}

3.网格布局

网格布局效果图

GridRecyclerView

GridRecyclerViewItem

GridAdapter

public class GridAdapter extends RecyclerView.Adapter {

    private Context mContext;
    private OnItemClickListener mListener;

    public GridAdapter(Context context, OnItemClickListener listener) {

        mContext = context;
        mListener = listener;
    }

    @NonNull
    @Override
    public GridAdapter.LinearViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new LinearViewHolder(LayoutInflater.from(mContext).inflate(R.layout.layout_grid_recycler_view_item, parent, false));
    }

    @Override
    public void onBindViewHolder(@NonNull GridAdapter.LinearViewHolder holder, final int position) {
        holder.textView.setText("Hello grid!");
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mListener.onClick(position);
//                Toast.makeText(mContext, "点击：" + position, Toast.LENGTH_SHORT).show();
            }
        });
    }

    @Override
    public int getItemCount() {
        return 30;
    }

    class LinearViewHolder extends RecyclerView.ViewHolder {
        private TextView textView;
        public LinearViewHolder(@NonNull View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.tv_title);
        }
    }

    public interface OnItemClickListener {
        void onClick(int pos);
    }
}

GridRecyclerViewActivity

public class GridRecyclerViewActivity extends AppCompatActivity {

    private RecyclerView mRvGrid;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_grid_recycler_view);
        mRvGrid = findViewById(R.id.rv_grid);
        mRvGrid.setLayoutManager(new GridLayoutManager(GridRecyclerViewActivity.this, 3));

        mRvGrid.setAdapter(new GridAdapter(GridRecyclerViewActivity.this, new GridAdapter.OnItemClickListener() {
            @Override
            public void onClick(int pos) {
                Toast.makeText(GridRecyclerViewActivity.this, "点击：" + pos, Toast.LENGTH_SHORT).show();
            }
        }));
    }
}