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import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.LinearLayoutManager;
import android.view.View;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.graphics.Canvas;
public class DividerItemDecoration extends RecyclerView.ItemDecoration {
private Drawable mDivider;
public DividerItemDecoration(Context context, AttributeSet attrs) {
final TypedArray a = context.obtainStyledAttributes(attrs, new int [] { android.R.attr.listDivider });
mDivider = a.getDrawable(0);
a.recycle();
}
public DividerItemDecoration(Drawable divider) { mDivider = divider; }
@Override
public void getItemOffsets (Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
if (mDivider == null) return;
if (parent.getChildPosition(view) < 1) return;
if (getOrientation(parent) == LinearLayoutManager.VERTICAL) outRect.top = mDivider.getIntrinsicHeight();
else outRect.left = mDivider.getIntrinsicWidth();
}
@Override
public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
super.onDrawOver(c, parent, state);
if (mDivider == null) { super.onDrawOver(c, parent); return; }
if (getOrientation(parent) == LinearLayoutManager.VERTICAL) {
final int left = parent.getPaddingLeft();
final int right = parent.getWidth() - parent.getPaddingRight();
final int childCount = parent.getChildCount();
for (int i=1; i < childCount; i++) {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
final int size = mDivider.getIntrinsicHeight();
final int top = child.getTop() - params.topMargin;
final int bottom = top + size;
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
} else { //horizontal
final int top = parent.getPaddingTop();
final int bottom = parent.getHeight() - parent.getPaddingBottom();
final int childCount = parent.getChildCount();
for (int i=1; i < childCount; i++) {
final View child = parent.getChildAt(i);
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
final int size = mDivider.getIntrinsicWidth();
final int left = child.getLeft() - params.leftMargin;
final int right = left + size;
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
}
private int getOrientation(RecyclerView parent) {
if (parent.getLayoutManager() instanceof LinearLayoutManager) {
LinearLayoutManager layoutManager = (LinearLayoutManager) parent.getLayoutManager();
return layoutManager.getOrientation();
} else throw new IllegalStateException("DividerItemDecoration can only be used with a LinearLayoutManager.");
}
}
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