在选项卡导航和列表导航之间切换

Question

bar.addTab(bar.newTab()
.setText("MyFragment")
.setTabListener(new TabListener<SomeFragment>(this, "myfargment", SomeFragment.class)));

public void onTabSelected(Tab tab, FragmentTransaction ft) {
    if (mFragment == null) {
        mFragment = Fragment.instantiate(mActivity, mClass.getName(), mArgs);
        ft.add(android.R.id.content, mFragment, mTag);
    } else {
        ft.attach(mFragment);
    }
}

@Override
public boolean onNavigationItemSelected(int itemPosition, long itemId) {
    switch (itemPosition) {
    case 0:
    //Replace the current fragment with FragmentA
        break;
    case 1:
    //Replace the current fragment with FragmentB
        break;
    case 2:
    //Replace the current fragment with FragmentC
        break;
    default:
        break;
    }
    return true;
}

我注意到一个有趣的行为：当导航模式设置为navigation_mode_tabs时，如果我将手机置于横向模式，它会将选项卡转换为列表，并保留片断和列表项（以前是选项卡项）之间的关联，如何根据需要而不是根据方向变化实现此结果？

Answer 1

我认为如果您在选项卡模式下手动设置为列表导航是不可能的。当我的一个应用程序落到“大”桶以下时，我为它设置了列表导航。以下是我如何使用导航监听器：

OnNavigationListener mNavigationListener = new OnNavigationListener()
{
int mLastPosition = -1;

@Override
public boolean onNavigationItemSelected(int itemPosition, long itemId)
{
    String selectedTag = mFragmentNames.get(itemPosition);

    FragmentManager fm = getSupportFragmentManager();
    Fragment fragment = fm.findFragmentByTag(selectedTag);
    FragmentTransaction ft = fm.beginTransaction();

    /** Used to avoid the same fragment being reattached. */
    if(mLastPosition != itemPosition)
    {
    /** Means there was a previous fragment attached. */
    if(mLastPosition != -1)
    {
        Fragment lastFragment = fm.findFragmentByTag(mFragmentNames.get(mLastPosition));
        if(lastFragment != null)
        ft.remove(lastFragment);
    }

    if(fragment == null)
    {
        /** The fragment is being added for the first time. */
        fragment = Fragment.instantiate(HomeActivity.this, selectedTag);
        ft.add(R.id.rootLayout, fragment, selectedTag);
        ft.commit();
    } else
    {
        ft.attach(fragment);
        ft.commit();
    }
    }
    /**
     * The newly attached fragment will be the last position if changed.
     */
    mLastPosition = itemPosition;

    return true;
}
};

变量mFragmentNames是一个将整数位置映射到片段名称ex的HashMap。“com.android.myProject.myFragment”

我希望这能有所帮助。