Android RecyclerView实现水平、垂直方向分割线

2019-12-12 02:29:26

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android RecyclerView不像过去的ListView那样随意的设置水平方向的分割线，如果要实现RecyclerView的水平/垂直分割线，则需要继承自RecyclerView.ItemDecoration重写getItemOffsets方法，从而增加水平/垂直分割线。

写一个例子。

MainActivity.Java：

package zhangphil.app;import android.content.Context;import android.graphics.Color;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.support.v7.widget.RecyclerView;import android.support.v7.widget.StaggeredGridLayoutManager;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;public class MainActivity extends AppCompatActivity {  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    RecyclerView mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);    // 两列    int spanCount = 2;    // StaggeredGridLayoutManager管理RecyclerView的布局。    StaggeredGridLayoutManager mLayoutManager = new StaggeredGridLayoutManager(spanCount, StaggeredGridLayoutManager.VERTICAL);    mRecyclerView.setLayoutManager(mLayoutManager);    //为RecyclerView增加分割线，水平和垂直方向都有。增加分割线值比如为32。    RecyclerViewItemDecoration decoration = new RecyclerViewItemDecoration(32);    mRecyclerView.addItemDecoration(decoration);    RecyclerViewAdapter mAdapter = new RecyclerViewAdapter(this);    mRecyclerView.setAdapter(mAdapter);  }  private class ItemViewHolder extends RecyclerView.ViewHolder {    private TextView text;    public ItemViewHolder(View itemView) {      super(itemView);      text = (TextView) itemView.findViewById(android.R.id.text1);      text.setTextColor(Color.WHITE);    }  }  public class RecyclerViewAdapter extends RecyclerView.Adapter<ItemViewHolder> {    private Context context;    public RecyclerViewAdapter(Context context) {      super();      this.context = context;    }    @Override    public ItemViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {      View view = View.inflate(context, android.R.layout.simple_list_item_1, null);      view.setBackgroundColor(Color.RED);      ItemViewHolder holder = new ItemViewHolder(view);      return holder;    }    @Override    public void onBindViewHolder(ItemViewHolder viewHolder, int pos) {      viewHolder.text.setText(String.valueOf(pos));    }    @Override    public int getItemCount() {      return 15;    }  }}

布局文件，很简单，就放一个RecyclerView，注意背景颜色的设置：

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:layout_width="match_parent"  android:layout_height="match_parent"  android:background="@android:color/holo_orange_light">  <android.support.v7.widget.RecyclerView    android:id="@+id/recyclerView"    android:layout_width="match_parent"    android:layout_height="match_parent">  </android.support.v7.widget.RecyclerView></RelativeLayout>

最关键的RecyclerViewItemDecoration.java：

package zhangphil.app;/** * Created by Phil on 2016/10/8. */import android.graphics.Rect;import android.support.v7.widget.RecyclerView;import android.view.View;/** * 为RecyclerView增加间距 * 预设2列，如果是3列，则左右值不同 */public class RecyclerViewItemDecoration extends RecyclerView.ItemDecoration {  private int space = 0;  private int pos;  public RecyclerViewItemDecoration(int space) {    this.space = space;  }  @Override  public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {    outRect.top = space;    //该View在整个RecyclerView中位置。    pos = parent.getChildAdapterPosition(view);    //取模    //两列的左边一列    if (pos % 2 == 0) {      outRect.left = space;      outRect.right = space / 2;    }    //两列的右边一列    if (pos % 2 == 1) {      outRect.left = space / 2;      outRect.right = space;    }  }}

代码运行结果：