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March 13, 2019 14:56
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Snap helper item decoration
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import android.content.Context; | |
import android.graphics.Point; | |
import android.graphics.Rect; | |
import android.support.v7.widget.RecyclerView; | |
import android.view.Display; | |
import android.view.View; | |
import android.view.ViewGroup; | |
import android.view.WindowManager; | |
public class OffsetItemDecoration extends RecyclerView.ItemDecoration { | |
private Context ctx; | |
public OffsetItemDecoration(Context ctx) { | |
this.ctx = ctx; | |
} | |
@Override | |
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) { | |
super.getItemOffsets(outRect, view, parent, state); | |
int offset = (int) (getScreenWidth() / (float) (2)) - view.getLayoutParams().width / 2; | |
ViewGroup.MarginLayoutParams lp = (ViewGroup.MarginLayoutParams) view.getLayoutParams(); | |
if (parent.getChildAdapterPosition(view) == 0) { | |
((ViewGroup.MarginLayoutParams) view.getLayoutParams()).leftMargin = 0; | |
setupOutRect(outRect, offset, true); | |
} else if (parent.getChildAdapterPosition(view) == state.getItemCount() - 1) { | |
((ViewGroup.MarginLayoutParams) view.getLayoutParams()).rightMargin = 0; | |
setupOutRect(outRect, offset, false); | |
} | |
} | |
private void setupOutRect(Rect rect, int offset, boolean start) { | |
if (start) { | |
rect.left = offset; | |
} else { | |
rect.right = offset; | |
} | |
} | |
private int getScreenWidth() { | |
WindowManager wm = (WindowManager) ctx.getSystemService(Context.WINDOW_SERVICE); | |
Display display = wm.getDefaultDisplay(); | |
Point size = new Point(); | |
display.getSize(size); | |
return size.x; | |
} | |
} |
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