A version of support DrawerLayout that can open the drawer X pixels... uses reflection to access the private members of DrawerLayout

gistfile1.txt

// example usage

// set up in XML and in class exactly the same as a DrawerLayout... then you can do something like this.. 

    peekableDrawerLayout.postDelayed(new Runnable() {
      @Override
      public void run() {
        peekableDrawerLayout.openDrawerToOffset(200.0F);
        peekableDrawerLayout.postDelayed(new Runnable() {
          @Override
          public void run() {
            peekableDrawerLayout.closeDrawers();
          }
        }, 1000);
      }
    }, 2000);

PeekableDrawerLayout.java

package android.support.v4.widget;

import android.content.Context;
import android.graphics.Point;
import android.os.Build;
import android.support.v4.view.GravityCompat;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.view.Display;
import android.view.Gravity;
import android.view.View;
import android.view.WindowManager;
import timber.log.Timber;

import java.lang.reflect.Field;

/**
 * uses reflection to manipulate the private fields of the super class to achieve a programmatic animated drawer open to a specified offset
 */
public class PeekableDrawerLayout extends DrawerLayout {
  WindowManager windowManager;

  private Field mLeftDraggerField;
  private Field mRightDraggerField;
  ViewDragHelper mRightDragger;
  ViewDragHelper mLeftDragger;

  public PeekableDrawerLayout(Context context) {
    super(context);
    init();
  }

  public PeekableDrawerLayout(Context context, AttributeSet attrs) {
    super(context, attrs);
    init();
  }

  public PeekableDrawerLayout(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    init();
  }

  protected void init() {
    windowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
    try {
      mLeftDraggerField = DrawerLayout.class.getDeclaredField("mLeftDragger");
      mLeftDraggerField.setAccessible(true);
      mRightDraggerField = DrawerLayout.class.getDeclaredField("mRightDragger");
      mRightDraggerField.setAccessible(true);
    } catch (NoSuchFieldException e) {
      Timber.e(e, "unfortunate and unforeseen problem manipulating ");
      throw new RuntimeException(e);
    }
  }

  public void openDrawerToOffset(float slideOffset) {
    final int childCount = getChildCount();
    for (int i = 0; i < childCount; i++) {
      final View child = getChildAt(i);
      if (child == null || !isDrawerView(child)) {
        continue;
      }
      final int gravity = ((LayoutParams) child.getLayoutParams()).gravity;
      final int absGravity = GravityCompat.getAbsoluteGravity(gravity, ViewCompat.getLayoutDirection(this));

      final ViewDragHelper helper;
      int finalLeft;
      if (absGravity == Gravity.LEFT) {
        helper = getLeftDragger();
        finalLeft = (int) (slideOffset - child.getWidth());
      } else {
        helper = getRightDragger();
        finalLeft = (int) (getDisplayWidth() - slideOffset);
      }

      helper.cancel();
      helper.smoothSlideViewTo(child, finalLeft, child.getTop());
      invalidate();
    }
  }

  public int getDisplayWidth() {
    Display display = windowManager.getDefaultDisplay();
    int width;
    if(Build.VERSION.SDK_INT >= 13) {
      Point size = new Point();
      display.getSize(size);
      width = size.x;
    } else {
      //noinspection deprecation
      width = display.getWidth();
    }
    return width;
  }

  public ViewDragHelper getLeftDragger() {
    if (mLeftDragger == null) {
      try {
        mLeftDragger = (ViewDragHelper) this.mLeftDraggerField.get(this);
      } catch (IllegalAccessException e) {
        Timber.e(e, "unfortunate and unforeseen problem manipulating ");
        throw new RuntimeException(e);
      }
    }
    return mLeftDragger;
  }

  public ViewDragHelper getRightDragger() {
    if (mRightDragger == null) {
      try {
        mRightDragger = (ViewDragHelper) this.mRightDraggerField.get(this);
      } catch (IllegalAccessException e) {
        Timber.e(e, "unfortunate and unforeseen problem manipulating ");
        throw new RuntimeException(e);
      }
    }
    return mRightDragger;
  }
}