停止片段自行重置答案

【问题标题】：Stopping a fragment resetting itself停止片段自行重置
【发布时间】：2014-01-22 18:51:04
【问题描述】：

我正在制作一个网络浏览器。我已经使用片段进行选项卡，但是当用户从一个选项卡转到另一个选项卡并再次返回时，webview 的 url 重置并且用户的 url 丢失了。我的问题是；片段切换时如何停止 webview 重置。我研究了左右和中心试图解决这个问题，但没有任何运气。谢谢！

public class HomeFragment extends Fragment {

public HomeFragment(){}

private WebView WebViewB1;
private ProgressBar Pbar1;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {

    View rootView = inflater.inflate(R.layout.fragment_home, container, false);

    Pbar1 = (ProgressBar) rootView.findViewById(R.id.progBar1);
    WebViewB1 = (WebView) rootView.findViewById(R.id.wvBrowserTab1);

    WebSettings webSettings = WebViewB1.getSettings();
    webSettings.setJavaScriptEnabled(true);
    WebViewB1.getSettings().setLoadWithOverviewMode(true);
    WebViewB1.getSettings().setUseWideViewPort(true);
    WebViewB1.getSettings().setBuiltInZoomControls(true);
    WebViewB1.getSettings().setAllowFileAccess(true);

    WebViewB1.setWebViewClient(new InsideWebViewClient());
    WebViewB1.setWebChromeClient(new WebChromeClient() {
        public void onProgressChanged(WebView view, int progress) 
        {
        if(progress < 100 && Pbar1.getVisibility() == ProgressBar.GONE){
            Pbar1.setVisibility(ProgressBar.VISIBLE);
        }
        Pbar1.setProgress(progress);
        if(progress == 100) {
            Pbar1.setVisibility(ProgressBar.GONE);
        }
     }
 });

        WebViewB1.loadUrl("http://google.com");

    return rootView;
}

}

下方的滑动菜单活动

public class MainActivity extends Activity {

private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;


private CharSequence mDrawerTitle;

private CharSequence mTitle;

private String[] navMenuTitles;
private TypedArray navMenuIcons;

private ArrayList<NavDrawerItem> navDrawerItems;
private NavDrawerListAdapter adapter;

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mTitle = mDrawerTitle = getTitle();

    navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);

    navMenuIcons = getResources()
            .obtainTypedArray(R.array.nav_drawer_icons);

    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    mDrawerList = (ListView) findViewById(R.id.list_slidermenu);

    navDrawerItems = new ArrayList<NavDrawerItem>();

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[0], navMenuIcons.getResourceId(0, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[1], navMenuIcons.getResourceId(1, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[2], navMenuIcons.getResourceId(2, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[3], navMenuIcons.getResourceId(3, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[4], navMenuIcons.getResourceId(4, -1)));

    navDrawerItems.add(new NavDrawerItem(navMenuTitles[5], navMenuIcons.getResourceId(5, -1)));

    navMenuIcons.recycle();

    mDrawerList.setOnItemClickListener(new SlideMenuClickListener());

    adapter = new NavDrawerListAdapter(getApplicationContext(),
            navDrawerItems);
    mDrawerList.setAdapter(adapter);

    getActionBar().setDisplayHomeAsUpEnabled(true);
    getActionBar().setHomeButtonEnabled(true);

    mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout,
            R.drawable.ic_drawer,
            R.string.app_name,
            R.string.app_name
    ) {
        public void onDrawerClosed(View view) {
            getActionBar().setTitle(mTitle);
            invalidateOptionsMenu();
        }

        public void onDrawerOpened(View drawerView) {
            getActionBar().setTitle(mDrawerTitle);
            invalidateOptionsMenu();
        }
    };
    mDrawerLayout.setDrawerListener(mDrawerToggle);

    if (savedInstanceState == null) {
        displayView(0);
    }
}
private class SlideMenuClickListener implements
        ListView.OnItemClickListener {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position,
            long id) {
        displayView(position);
    }
}
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main, menu);

    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (mDrawerToggle.onOptionsItemSelected(item)) {
        return true;
    }
    switch (item.getItemId()) {
    case R.id.action_settings:
        return true;
    default:
        return super.onOptionsItemSelected(item);
    }
}

@Override
public boolean onPrepareOptionsMenu(Menu menu) {
    boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
    menu.findItem(R.id.action_settings).setVisible(!drawerOpen);
    return super.onPrepareOptionsMenu(menu);
}

private void displayView(int position) {
    Fragment fragment = null;

    switch (position) {
    case 0:
        fragment = new HomeFragment();
        break;
    case 1:
        fragment = new Tab2();
        break;
    case 2:
        fragment = new Tab3();
        break;
    case 3:
        fragment = new Tab4();
        break;
    case 4:
        fragment = new Tab5();
        break;
    case 5:
        fragment = new Tab6();
        break;

    default:
        break;
    }

    if (fragment != null) {
        FragmentManager fragmentManager = getFragmentManager();
        fragmentManager.beginTransaction()
                .replace(R.id.frame_container, fragment).commit();

        mDrawerList.setItemChecked(position, true);
        mDrawerList.setSelection(position);
        setTitle(navMenuTitles[position]);
        mDrawerLayout.closeDrawer(mDrawerList);
    } else {
        Log.e("MainActivity", "Error in creating fragment");
    }
}

@Override
public void setTitle(CharSequence title) {
    mTitle = title;
    getActionBar().setTitle(mTitle);
}

@Override
protected void onPostCreate(Bundle savedInstanceState) {
    super.onPostCreate(savedInstanceState);
    mDrawerToggle.syncState();
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    mDrawerToggle.onConfigurationChanged(newConfig);
}
 }

【问题讨论】：

任何代码显示您如何管理片段中的浏览器/webview？
@Stan 我添加了其中一个片段的活动。
你确定你的片段在你离开时没有被系统杀死？看起来每次您返回片段时都会触发 onCreateView，这就是 webview 重新加载的原因。您可以尝试将视图保持为属性链接，并检查其是否为 nulll 在 onCreate anf 中，如果不是，则将其作为视图返回
@Stan 抱歉，我不明白您将视图链接为属性是什么意思。
我的意思是类或字段的属性，如private View view。

标签： android android-fragments webview android-webview

【解决方案1】：

好的，我不确定它是否是个好主意，但我正在谈论以下内容：

    public abstract class AbstractFragment extends Fragment {

        private View mFragmentView;
        protected View getOnCreateView(LayoutInflater inflater, int layoutId){

             if (mFragmentView== null)
                 mFragmentView = inflater.inflate(layoutId, null);
             else
                 ((ViewGroup) mFragmentView.getParent()).removeView(mFragmentView);

             return mFragmentView;
        }


// this method needed to detect if fragment's view init is needed
// via initView() - its the method where you do findViewById()
// and sets up your webveiw, etc. The idea is to set up the view
// only once - in case when it has not been init-ed
// this will prevent your webview from reload from the start url
            protected boolean isFragmentViewInitialized;
            @Override
            public void onStart() {
                super.onStart();

                if (!isFragmentViewInitialized){
                    isFragmentViewInitialized = true;
                    initView();
                }

    }

        // use this method to setup the view
        public abstract void initView();

这个想法是通过你需要保持活力的每个片段来扩展这个片段，并从onCreate() 调用它的getOnCreateView，例如：

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            return getOnCreateView(inflater,R.layout.activity_about);
        }
        public void initView(){
            View rootView = getView();
Pbar1 = (ProgressBar) rootView.findViewById(R.id.progBar1);
    WebViewB1 = (WebView) rootView.findViewById(R.id.wvBrowserTab1);

    WebSettings webSettings = WebViewB1.getSettings();
    webSettings.setJavaScriptEnabled(true);
    WebViewB1.getSettings().setLoadWithOverviewMode(true);
    WebViewB1.getSettings().setUseWideViewPort(true);
    WebViewB1.getSettings().setBuiltInZoomControls(true);
    WebViewB1.getSettings().setAllowFileAccess(true);

    WebViewB1.setWebViewClient(new InsideWebViewClient());
    WebViewB1.setWebChromeClient(new WebChromeClient() {
        public void onProgressChanged(WebView view, int progress) 
        {
        if(progress < 100 && Pbar1.getVisibility() == ProgressBar.GONE){
            Pbar1.setVisibility(ProgressBar.VISIBLE);
        }
        Pbar1.setProgress(progress);
        if(progress == 100) {
            Pbar1.setVisibility(ProgressBar.GONE);
        }
     }
 });

        WebViewB1.loadUrl("http://google.com");
        }

【讨论】：

((ViewGroup) mThisView.getParent()).removeView(mFragmentView); “mThisView”无法解析，我不确定它的定义是什么。您的意思是扩展我不想通过 AbstractFragment 类重置的任何片段吗？感谢您的帮助
有一个错误ThisView is mFragmentView，所以我编辑了src - 必须是一个工作的smaple。是的，我是认真的。您不想重置的每个片段都必须从此 AbstractFragment 扩展。如果它有帮助，你也应该接受答案 4u。
感谢您的帮助，不过还有最后一个问题。我是否在“public abstract void initView();”下设置视图？在 AbstractFragment src 或当前的下。对不起，我很痛苦，我还在学习。 :)
如您所见，initView() 是 ABSTRACT 方法（我假设您知道它的含义，如果不知道，那么您应该阅读并学习它）。这意味着您必须在从 AbstractFragment 扩展的每个类中覆盖它（这就是为什么它的名称中有 Abstract 字）。是的，因为您必须覆盖 initView() 它是您设置视图的地方。它清楚地显示在 src 的第二部分 - 你看不到我将你的代码部分移动到 initView() 吗？

【解决方案2】：

由于我的标签监听器，每次重新选择片段时都会重新加载片段

if (fragment != null) {
    FragmentManager fragmentManager = getFragmentManager();
    fragmentManager.beginTransaction()
            .replace(R.id.frame_container, fragment).commit();

做了一个更好的tabListener之后的东西在哪里A-OK。检查此链接以了解如何改进选项卡侦听器 - http://developer.android.com/guide/topics/ui/actionbar.html#Tabs

【讨论】：

我知道您已经回答了您的问题，但事实证明，在处理您处理的同一问题时，此线程对我非常有帮助：stackoverflow.com/questions/13149446/…