Adding dividers to a RecyclerView

!!Android_Recycler_deviders.md

RecyclerView - Adding Dividers

How to add deviders between recyclerview items.

Based on the book Pro Android UI.

01_dividers.java

public class ItemDivider extends RecyclerView.ItemDecoration {

  Private Drawable divider; 
 
  public ItemDivider(Context context) { 
        final TypedArray styledAttributes = context.obtainStyledAttributes(ATTRS); 
        divider = styledAttributes.getDrawable(0); 
        styledAttributes.recycle(); 
    } 
  
  
public ItemDivider(Context context, int resId) { 
    divider = ContextCompat.getDrawable(context, resId); 
} 

    

  @Override 
  public void onDraw(Canvas canvas, RecyclerView parent, RecyclerView.State state) { 
    int left = parent.getPaddingLeft(); 
    int right = parent.getWidth() - parent.getPaddingRight(); 
 
    int count = parent.getChildCount(); 
    for (int i = 0; i < count; i++) { 
        View child = parent.getChildAt(i); 
 
        RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams(); 
 
        int top = child.getBottom() + params.bottomMargin; 
        int bottom = top + divider.getIntrinsicHeight(); 
 
        divider.setBounds(left, top, right, bottom); 
        divider.draw(canvas); 
    } 
} 
  
}

02_item_divider.xml

<?xml version="1.0" encoding="utf-8"?> 
<shape xmlns:android="http://schemas.android.com/apk/res/android" 
    android:shape="rectangle"> 
     
    <size android:height="1dp" /> 
    <solid android:color="@color/colorPrimaryDark" /> 
     
</shape> 

03_activity.java

onCreare(){
...
  recyclerView.addItemDecoration(new ItemDivider(this, R.drawable.item_divider)); 
...
}