com.example.android.common / view / SlidingTabLayout - 按下时标签标题的重影：返回

Question

我一直在玩com.example.android.common/view/SlidingTabLayout个例子，并且遇到了一个小问题。我知道如何解决/解决它，但我正在努力理解这个问题。

我已经创建了一个带有六个标签的小应用程序，显示我想要的wot，通常它的行为与预期一致，但是如果我快速浏览选项卡之间，按下标签标题，那么我点击后退按钮创建一个新选项卡标题视图，并将其附加到populateTabStrip（）中的mTabStrip，从而生成一组标签标题。问题只发生在导航是快速的时候，以悠闲的方式点击标签并且问题没有出现，所以假设它与垃圾收集有关，请参阅下文。无论如何，想知道是否有人能解释幕后发生的事情。

来自SlidingTabBasicFragment.java的

：

private void createAdapters(View view){
    Log.v(TAG, "createAdapters()");
    try {
        //TODO createAdapters() work out why the app's ghosting
        ViewPager mViewPager = (ViewPager) view.findViewById(R.id.viewpager);
        int currentItem = mViewPager.getCurrentItem();

        SamplePagerAdapter testAdaptor = (SamplePagerAdapter)mViewPager.getAdapter();
        if ( testAdaptor == null ) {
            Log.v(TAG, "createAdapters() - new SamplePagerAdapter() to be added");
            mViewPager.setAdapter(new SamplePagerAdapter());
        }

        mViewPager.setCurrentItem(currentItem);

        SlidingTabLayout mSlidingTabLayout = (SlidingTabLayout) view.findViewById(R.id.sliding_tabs);
        mSlidingTabLayout.setViewPager(mViewPager);

        rebuildViews = false;
    } catch (NullPointerException e) {
        Toast.makeText(getActivity(), e.getMessage(), Toast.LENGTH_LONG).show();
    }
}

来自主要活动：

@Override
public void onNavigationDrawerItemSelected(int position, int lastPosition) {
    Log.v(TAG, "onNavigationDrawerItemSelected - entered");
    Intent intent;
    String createdFileName;

    // update the main content by replacing fragments

    FragmentTransaction transaction = getFragmentManager().beginTransaction();
    onSectionAttached(position + 1);

    switch (position) {
        case 0: // Main - Vitals
            Log.v(TAG, "adding a 'vitalFrag' to the fragment stack");
            transaction.replace(R.id.main_content_fragment, new SlidingTabsBasicFragment(), "vitalFrag").addToBackStack(null).commit();
            break;
        case 1: // Settings
...


@Override
public void onBackPressed(){
    Log.v(TAG, "onBackPressed - entered");
    // Catch back action and pops from backStack
    // (if you called previously to addToBackStack() in your transaction)
    if (getFragmentManager().getBackStackEntryCount() > 0){
        // If Open, close the Navigation Drawer, as can be confusing if the Navigation
        // Drawer shows a different Option / Fragment as selected, after the previous
        // fragment has been restored
        NavigationDrawerFragment mNavFrag = (NavigationDrawerFragment)
                getFragmentManager().findFragmentById(R.id.navigation_drawer);
        if (mNavFrag != null && mNavFrag.isVisible() && mNavFrag.isDrawerOpen()) {
            mNavFrag.closeDrawer();
            mClosedDrawer = true;
        }
        // Pull back the last fragment
        getFragmentManager().popBackStack();
    }
    // Default action on back pressed
    else super.onBackPressed();
}


@Override
public void onVitalChanged() {
    Log.v(TAG, "onVitalChanged() entered");
    requestBackup();
    //TODO onVitalChanged() - finish - just invalidate the views
    SlidingTabsBasicFragment fragment = (SlidingTabsBasicFragment)  getFragmentManager().findFragmentByTag("vitalFrag");
    if (fragment != null) {
        //Log.v(TAG, "onVitalChanged() asking fragment to rebuild the Vital views");
        //fragment.setRebuildViews();
        Log.v(TAG, "onVitalChanged - replace the Results fragment");
        FragmentTransaction transaction = getFragmentManager().beginTransaction();
        transaction.replace(R.id.main_content_fragment, new SlidingTabsBasicFragment(), "vitalFrag")
            .addToBackStack(null)
            .commitAllowingStateLoss();
    }
}

来自其中一个片段：

....

@Override
public void onResume() {
    Log.v(TAG, "onResume() - entered");
    if (rebuildViews) {
        invalidateViews(this.getView());    
    }
    ActionBar mActionBar = getActivity().getActionBar();
    if (mActionBar != null)
        mActionBar.setTitle(R.string.action_history);
    super.onResume();
}