RecyclerView自定义分割线————列表分割线

//添加分割线 MyDecoration decoration=new MyDecoration(MainActivity.this,MyDecoration.VERTICAL_LIST); rv.addItemDecoration(decoration); package xixinxin.bawie.com.recyleclerview; 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.GridLayoutManager; import android.support.v7.widget.RecyclerView; import android.support.v7.widget.StaggeredGridLayoutManager; import android.view.View; public class MyDecoration extends RecyclerView.ItemDecoration { private Context mContext; private Drawable mDivider; private int mOrientation; public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL; public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL; //我们通过获取系统属性中的listDivider来添加，在系统中的AppTheme中设置 public static final int[] ATRRS = new int[]{ android.R.attr.listDivider }; public MyDecoration(Context context, int orientation) { this.mContext = context; final TypedArray ta = context.obtainStyledAttributes(ATRRS); this.mDivider = ta.getDrawable(0); ta.recycle(); setOrientation(orientation); } //设置屏幕的方向 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, RecyclerView.State state) { if (mOrientation == HORIZONTAL_LIST){ drawVerticalLine(c, parent, state); }else { drawHorizontalLine(c, parent, state); } } //画横线, 这里的parent其实是显示在屏幕显示的这部分 public void drawHorizontalLine(Canvas c, RecyclerView parent, RecyclerView.State state){ int left = parent.getPaddingLeft(); int right = parent.getWidth() - parent.getPaddingRight(); final int childCount = parent.getChildCount(); for (int i = 0; i < childCount; i++){ final View child = parent.getChildAt(i); //获得child的布局信息 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); //Log.d("wnw", left + " " + top + " "+right+" "+bottom+" "+i); } } //画竖线 public void drawVerticalLine(Canvas c, RecyclerView parent, RecyclerView.State state){ int top = parent.getPaddingTop(); int bottom = parent.getHeight() - parent.getPaddingBottom(); final int childCount = parent.getChildCount(); for (int i = 0; i < childCount; i++){ final View child = parent.getChildAt(i); //获得child的布局信息 final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams)child.getLayoutParams(); final int left = child.getRight() + params.rightMargin; final int right = left + mDivider.getIntrinsicWidth(); mDivider.setBounds(left, top, right, bottom); mDivider.draw(c); } } //由于Divider也有长宽高，每一个Item需要向下或者向右偏移 @Override public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) { if(mOrientation == HORIZONTAL_LIST){ //画横线，就是往下偏移一个分割线的高度 outRect.set(0, 0, 0, mDivider.getIntrinsicHeight()); }else { //画竖线，就是往右偏移一个分割线的宽度 outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0); } } }