Android navigation drawer trigger area is too small

Question

I am working on the navigation drawer provide by the offical android library. And I swift it from left side, the problem is by default the trigger area is too small , the user have to touch at very left to open the drawer, are there any way to custom the size , or enlarge the size? Thanks for helping.

Answer 1

You can do something like this:

private void setLeftMargin() {
    java.lang.reflect.Field mDragger = null;
    try {
        mDragger = mDrawerLayout.getClass()
                .getDeclaredField("mLeftDragger");
    } catch (NoSuchFieldException e2) {
        // TODO Auto-generated catch block
        e2.printStackTrace();
    }
    mDragger.setAccessible(true);
    ViewDragHelper draggerObj = null;
    try {
        draggerObj = (ViewDragHelper) mDragger.get(mDrawerLayout);
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    java.lang.reflect.Field mEdgeSize = null;
    try {
        mEdgeSize = draggerObj.getClass().getDeclaredField("mEdgeSize");
    } catch (NoSuchFieldException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
    mEdgeSize.setAccessible(true);
    int edge = 0;
    try {
        edge = mEdgeSize.getInt(draggerObj);
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    try {
        mEdgeSize.setInt(draggerObj, edge * 1);
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}

It will set left side area as per your requirement.You can set int edge = valueYouNeed;Hope it will help you.

Answer 2

kotlin version of AndiM answer

private fun setDrawerEdge(mDrawerLayout: DrawerLayout, isLeftDrawer: Boolean = true) {
    try {
        val manager = mActivity.getSystemService(Context.WINDOW_SERVICE) as WindowManager
        val width = DisplayMetrics().also { manager.defaultDisplay.getMetrics(it) }.widthPixels

        val viewDragHelper = mDrawerLayout::class.java
                .getDeclaredField(if (isLeftDrawer) "mLeftDragger" else "mRightDragger")
                .apply { isAccessible = true }
                .run { get(mDrawerLayout) as ViewDragHelper }

        viewDragHelper.let { it::class.java.getDeclaredField("mEdgeSize") }
                .apply { isAccessible = true }
                .apply { setInt(viewDragHelper, width/2) }

    } catch (e: Exception) {
        e.printStackTrace()
    }
}