Question

在片段中，我以编程方式将片段添加到导航抽屉中，然后从右侧打开抽屉。请注意，我无法直接访问DrawerLayout的xml文件，因此需要编程解决方案。抽屉从右侧打开并正确关闭，我保留了抽屉的打开/关闭状态，并根据状态对该配置进行了更改。

问题在于，即使更改了基于saveInstanceState布尔值的打开/关闭状态，配置更改时抽屉也会关闭（我可以看到抽屉处于关闭状态）。我在closeDrawer中的所有DrawerLayout.class方法中都放置了调试器，但是没有被使用。

更新：我想我知道问题出在哪里，但是我不确定如何在不扩展DrawerLayout本身的情况下解决该问题。在我的情况下，在DrawerLayout#findDrawerWithGravity中调用的DrawerLayout#onRestoreInstanceState返回null。

@Override
public void onSaveInstanceState(Bundle outState)
{
    super.onSaveInstanceState(outState);
    outState.putBoolean(STATE_DRAWER_OPEN,
        getDrawerLayout() == null ? false : getDrawerLayout().isDrawerOpen(Gravity.RIGHT));
}

@Override
public void onActivityCreated(Bundle savedInstanceState)
{
    super.onActivityCreated(savedInstanceState);
    if (savedInstanceState != null)
        isDrawerOpen = savedInstanceState.getBoolean(STATE_DRAWER_OPEN);
}

private void setDrawer() //this is called in onCreate
{
    DrawerLayout drawer = getActivity().findViewById(R.id.drawer_layout);
    if (drawer == null)
        drawer = getDrawerLayout();

    View existing = drawer.findViewById(R.id.m_drawer_container);
    if (existing != null)
        drawer.removeView(existing);

    drawer.setFocusableInTouchMode(false);
    drawer.addDrawerListener(this);

    FrameLayout fragmentContainer = new FrameLayout(getActivity());
    fragmentContainer.setId(R.id.m_drawer_container);
    final DrawerLayout.LayoutParams layoutParams = new DrawerLayout.LayoutParams(
        getResources().getDimensionPixelSize(R.dimen.m_drawer_max_width),
        ViewGroup.LayoutParams.MATCH_PARENT, Gravity.RIGHT);
    drawer.addView(fragmentContainer, layoutParams);

    FragmentManager fragmentManager = getFragmentManager();
    MyDrawerFragment mDrawerFragment = null;
    Fragment frag = fragmentManager.findFragmentByTag(TAG_DRAWER_FRAGMENT);
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
    if (frag != null && frag.isAdded())
        fragmentTransaction.remove(frag);
    mDrawerFragment = MyDrawerFragment.newInstance(myArgs);
    fragmentTransaction.add(R.id.m_drawer_container, drawerFragment, TAG_DRAWER_FRAGMENT);
    fragmentTransaction.commitAllowingStateLoss();

    if (isDrawerOpen)
        drawer.openDrawer(Gravity.RIGHT);
}

Answer 1

结果是，从配置更改还原时，答案是调用drawer.openDrawer(Gravity.RIGHT, false);以禁用动画。原因是调用drawer.openDrawer(Gravity.RIGHT)的动画默认情况下设置为true，而深入研究该方法最终会导致DrawerLayout.java中的此代码块，从而导致宽度计算不正确，从而导致抽屉为“隐藏”：

DrawerLayout.java

else if (animate) {
    lp.openState |= LayoutParams.FLAG_IS_OPENING;

    if (checkDrawerViewAbsoluteGravity(drawerView, Gravity.LEFT)) {
        mLeftDragger.smoothSlideViewTo(drawerView, 0, drawerView.getTop());
    } else {
        mRightDragger.smoothSlideViewTo(drawerView, getWidth() - drawerView.getWidth(),
                drawerView.getTop());
    }

解决方案是从配置更改还原时将动画设置为false。

if (isDrawerOpen && isRestoreFromConfigChange)
    drawer.openDrawer(Gravity.RIGHT, false);

导航抽屉在配置更改时关闭

1 个答案: