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Set drag margin for Android Navigation Drawer

Posted by: admin April 23, 2020 Leave a comment

Questions:

I am using the new Navigation Drawer in my app. It is great except I have not found an easy way to set how the drawer is open. The default behavior is drag from the left edge of the screen to open. This is fine, unless the phone/table has a case on and the edge of phone can not be touched. I would like to allow the user to touch and drag from a margin of the screen to the left. This is easy to set with other nav drawer libs(Sliding lib). I have not seen anything with Google’s lib unfortunately.

There is an onTouchEvent() method for the NavigationLayout that could may be used. Of course you could listen to all touch events and trigger an openDrawer, but was hoping for an easy way with less code. Any ideas?

How to&Answers:

Here I’ve found a solution via reflections

DrawerLayout mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
Field mDragger = mDrawerLayout.getClass().getDeclaredField(
        "mLeftDragger");//mRightDragger for right obviously
mDragger.setAccessible(true);
ViewDragHelper draggerObj = (ViewDragHelper) mDragger
        .get(mDrawerLayout);

Field mEdgeSize = draggerObj.getClass().getDeclaredField(
        "mEdgeSize");
mEdgeSize.setAccessible(true);
int edge = mEdgeSize.getInt(draggerObj);

mEdgeSize.setInt(draggerObj, edge * 5); //optimal value as for me, you may set any constant in dp