android - Navigation Drawer 的 fragment 管理

Question

我正在开发一个应用程序，我只使用 1 个主要 Activity 和多个 fragment ，包括 ViewPager 、自定义视频/图片库、全屏 fragment (没有工具栏或底部导航按钮)。我不确定这是否是好的做法，但我面临的问题很少。

上图是实际的 App 层次结构。关注我面临的问题。

1. 当按下后退按钮或通过单击按钮或某些链接前进时，工具栏不会更改 fragment 的标题。
2. 如果我通过 使用 getSupportActionBar().setDisplayHomeAsUpEnabled(true); 更改为后退箭头，导航汉堡将继续显示，然后后退箭头会打开抽屉，但不会返回到最后一个 fragment 。
3. 当按下后退按钮或直接跳转到某个 fragment 时 fragment 状态丢失。
4. 使用单个 Activity 在 Fragment 中完成所有任务是否是好的做法。

我还在整个应用程序中使用单个工具栏。 工具栏.xml

<android.support.v7.widget.Toolbar
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="@color/primary"
    app:contentInsetLeft="0dp"
    app:contentInsetStart="0dp"
    app:contentInsetStartWithNavigation="0dp"
    android:fitsSystemWindows="true"
    app:layout_collapseMode="pin"
    app:layout_scrollFlags="scroll|exitUntilCollapsed">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/toolbar_connections"
        android:visibility="visible"
        android:orientation="horizontal">
    <ImageView
        android:layout_width="35dp"
        android:layout_height="match_parent"
        android:id="@+id/appLogo"
        android:layout_gravity="center_vertical" />
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_vertical|center_horizontal"
            android:textSize="22sp"
            android:id="@+id/activityTitle"
            android:textColor="@color/primary_text"
            />

    </LinearLayout>

    <LinearLayout
        android:id="@+id/toolbar_chat"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:visibility="gone"
        android:orientation="horizontal">

        <de.hdodenhof.circleimageview.CircleImageView
            android:layout_width="50dp"
            android:layout_height="50dp"
            android:layout_gravity="center_vertical"
            android:layout_marginRight="5dp"
            android:src="@drawable/baby"
            android:id="@+id/User_Image_Toolbar"/>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:id="@+id/User_Name_Toolbar"
                android:textSize="17sp"
                android:textStyle="bold"
                android:layout_marginBottom="5dp"
                android:text="My Name"
                />
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Online"
                android:textStyle="italic"
                android:id="@+id/User_Online_Status_Toolbar"
                android:layout_marginBottom="5dp"
                android:layout_below="@+id/User_Name_Toolbar" />
        </LinearLayout>
    </LinearLayout>


</android.support.v7.widget.Toolbar>

抽屉导航(所有 fragment 的父 Activity )

public class Navigation_Drawer extends AppCompatActivity implements UserData {

    Toolbar toolbar;
    DrawerLayout drawerLayout;
    NavigationView navigationView;
    String navTitles[];
    TypedArray navIcons;
    RecyclerView.Adapter recyclerViewAdapter;
    ActionBarDrawerToggle drawerToggle;
    public static final String TAG = "###Navigation Drawer###";
    boolean nextScreen;
    //Header
    ImageView headerImage,headerUserImage;
    TextView userName,userViews;
    Context context = this;
    //Setting Tabs
    ViewPager viewPager;
    TabAdapter tabAdapter;

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);           
        setContentView(R.layout.navigation_drawer);    

        //Initialise Views
        drawerLayout = findViewById(R.id.Navigation_Drawer_Main);
        navigationView = findViewById(R.id.nvView);
        setupToolbar();
        navigationView.setItemIconTintList(null);
        setupDrawerContent(navigationView);
        settingHeaderItems();
        drawerToggle = setupDrawerToggle();
        getSupportActionBar().setHomeButtonEnabled(true);

        drawerLayout.addDrawerListener(drawerToggle);
        viewPager = findViewById(R.id.Navigation_Drawer_ViewPager);
        tabAdapter = new TabAdapter(getFragmentManager(), this, false);    


        viewPager.setAdapter(tabAdapter);

    }


    public void setupToolbar() {
        toolbar = findViewById(R.id.Navigation_Drawer_toolbar);
        setSupportActionBar(toolbar);
    }
    private ActionBarDrawerToggle setupDrawerToggle() {
        // NOTE: Make sure you pass in a valid toolbar reference.  ActionBarDrawToggle() does not require it
        // and will not render the hamburger icon without it.
        //return new ActionBarDrawerToggle(this, drawerLayout, toolbar, R.string.drawer_open,  R.string.drawer_close);
        return new ActionBarDrawerToggle(this, drawerLayout,toolbar, R.string.drawer_open,  R.string.drawer_close);
    }    


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        //  inflater.inflate(R.menu.main_menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        //Handle Item Selection

        return super.onOptionsItemSelected(item);
    }
    private void setupDrawerContent(NavigationView navigationView) {
        navigationView.setNavigationItemSelectedListener(
                new NavigationView.OnNavigationItemSelectedListener() {
                    @Override
                    public boolean onNavigationItemSelected(MenuItem menuItem) {
                        selectDrawerItem(menuItem);
                        return true;

                    }

                });

    }





    public void ChangeFragment_ViewPager(int position, boolean outside) {
        if (outside) {
            Log.d(TAG, "Change Fragment Calling From Outside");
            tabAdapter = new TabAdapter(getFragmentManager(), this, false);
            viewPager.setAdapter(tabAdapter);
        }

        viewPager.setCurrentItem(position);
    }

    @Override
    public void onBackPressed() {
        super.onBackPressed();
        showSystemUI();
        Log.d(TAG, "On Back Pressed");

    }

    public void showSystemUI() {
        if (getWindow() != null) {
            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS);
            getWindow().clearFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            getSupportActionBar().show();
        } else {
            return;
        }

    }


    public void selectDrawerItem(MenuItem menuItem) {
        // Create a new fragment and specify the fragment to show based on nav item clicked
        Fragment fragment = null;


        switch (menuItem.getItemId()) {

            case R.id.HeaderImageView:
                fragment = new EditProfile();
                break;
            case R.id.home_Fragment:
                Log.d(TAG,"Home Fragment Pressed ");
                getFragmentManager().popBackStack(null, android.app.FragmentManager.POP_BACK_STACK_INCLUSIVE);
                ChangeFragment_ViewPager(0,false);
                // Highlight the selected item has been done by NavigationView
                menuItem.setChecked(true);
                // Set action bar title
                setTitle(menuItem.getTitle());
                // Close the navigation drawer
                drawerLayout.closeDrawers();
                return;

            case R.id.ppl_Fragment:
                Log.d(TAG,"PPL Fragment Pressed ");
                ChangeFragment_ViewPager(1,false);
                // Highlight the selected item has been done by NavigationView
                menuItem.setChecked(true);
                // Set action bar title
                setTitle(menuItem.getTitle());
                // Close the navigation drawer
                drawerLayout.closeDrawers();
                return;

            case R.id.message_Fragment:
                Log.d(TAG,"Message Fragment Pressed ");
                fragment = new  Messages_Fragment();

                break;

            case R.id.addMedia_Fragment:
                Log.d(TAG,"Add Media Fragment Pressed ");
                fragment = new UserProfile_Photos();

                break;

            case R.id.invite_Fragment:
                Log.d(TAG,"Invite Fragment Pressed ");
                //fragmentClass = fragment_1.class;
                onInviteClicked();
                // Highlight the selected item has been done by NavigationView
                menuItem.setChecked(true);
                // Set action bar title
                setTitle(menuItem.getTitle());
                // Close the navigation drawer
                drawerLayout.closeDrawers();
                return;


            case R.id.setting_Fragment:
                Log.d(TAG,"Setting Fragment Pressed ");
                fragment = new  Setting_NavigationDrawer();

                break;

            case R.id.help_Fragment:
                Log.d(TAG,"Help Fragment Pressed ");
                //fragmentClass = fragment_1.class;
                fragment=new FullScreen_WebView();
                Bundle urlToSend=new Bundle();
                urlToSend.putString("webViewURL","http://boysjoys.com/test/Android/Data/help.php");
                //urlToSend.putString("webViewURL",chat_wrapper.getGoogleSearch().get(2));
                fragment.setArguments(urlToSend);
                FragmentTransaction transaction=((Activity)context).getFragmentManager().beginTransaction();
                //fragmentTrasaction.replace(R.id.Chat_Screen_Main_Layout,gallery);
                //transaction.replace(R.id.Chat_Screen_Main_Layout,fullScreen_webView);
                transaction.replace(R.id.Navigation_Main_Layout,fragment);
                transaction.addToBackStack(null);
                transaction.commit();

                // Highlight the selected item has been done by NavigationView
                menuItem.setChecked(true);
                // Set action bar title
                setTitle(menuItem.getTitle());
                // Close the navigation drawer
                drawerLayout.closeDrawers();
                return;

            case R.id.signOut_Fragment:
                new CheckLoginStatus(this, 0).execute();
                new Send_Session_Logout(this).execute();
                drawerLayout.closeDrawers();
                return;

        }


        FragmentTransaction fragmentTransaction=getFragmentManager().beginTransaction();
        fragmentTransaction.add(R.id.Navigation_Main_Layout, fragment);
        fragmentTransaction.setCustomAnimations(R.animator.enter_anim,R.animator.exit_anim);
        fragmentTransaction.addToBackStack(null);
        fragmentTransaction.commit();

        // Highlight the selected item has been done by NavigationView

        menuItem.setChecked(true);

        // Set action bar title

        setTitle(menuItem.getTitle());

        // Close the navigation drawer

        drawerLayout.closeDrawers();

    }
    private void settingHeaderItems(){
        View HeaderLayout = navigationView.inflateHeaderView(R.layout.navigation_header_image);
        //Main Screen Tabs With VIew Pager
        headerImage = HeaderLayout.findViewById(R.id.HeaderImageView);
        headerImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                FragmentTransaction fragmentTransaction=getFragmentManager().beginTransaction();
                fragmentTransaction.replace(R.id.Navigation_Main_Layout, new EditProfile());
                fragmentTransaction.setCustomAnimations(R.animator.enter_anim,R.animator.exit_anim);
                fragmentTransaction.addToBackStack(null);
                fragmentTransaction.commit();
                drawerLayout.closeDrawers();
            }
        });
        headerUserImage = HeaderLayout.findViewById(R.id.HeaderProfilePicture);
        userName = HeaderLayout.findViewById(R.id.myImageViewText);
        userViews = HeaderLayout.findViewById(R.id.profileViews);
        if (Session.getUserCover().equals("Invalid Image")){
            headerImage.setBackgroundResource(R.drawable.cam_icon);
        }else {
            Log.d(TAG,"Path Of Cover Photo "+Session.getUserCover());
            Bitmap coverPhoto= BitmapFactory.decodeFile(Session.getUserCover());
            headerImage.setImageBitmap(coverPhoto);
            //  Glide.with(context).load(Session.getUserCover()).apply(new RequestOptions().skipMemoryCache(true).onlyRetrieveFromCache(false).diskCacheStrategy(DiskCacheStrategy.NONE)).into(holder.HeaderImage);
        }
        Bitmap bitmap = BitmapFactory.decodeFile(Session.getUserImage());

        userName.setText(Session.getUserFname()+" "+Session.getUserLname());
        headerUserImage.setImageBitmap(bitmap);
        if (Session.getProfileCounter().equals("0")){
            userViews.setText("No Profile VIsits");
        }
        else {
            userViews.setText("Profile views: "+ Session.getProfileCounter());
        }
    }

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

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

我厌倦了解决这个问题，经过几个月的谷歌搜索和 stackoverflow，我仍然陷入同样的​​问题。

第 1 点的问题示例:- 当抽屉导航首先加载时，一切看起来都不错， View 寻呼机根据 fragment 更改标题。然后，如果我单击抽屉导航的菜单，它也会打开另一个 fragment (例如:最近的消息)。然后标题更改成功，但是当我按下后退按钮或尝试按下调用 viewpager 的主页按钮时，标题保持与以前相同，即最近的消息。

像这样在每个 fragment 中设置标题。

toolbar = (Toolbar) getActivity().findViewById(R.id.Navigation_Drawer_toolbar);
        ImageView appLogo = toolbar.findViewById(R.id.appLogo);
        TextView fragmentTitle = toolbar.findViewById(R.id.activityTitle);
        appLogo.setImageResource(DrawableImage);
        fragmentTitle.setText(Title);

Answer 1

如果应用程序必须使用应该出现在所有 View 中的 Navigation Drawer，那么应该使用 Fragment。这不是一个坏习惯。

1. 工具栏不会更改 fragment 的标题，当按下后退按钮或 单击按钮或某个链接继续前进。

在Base Activity中创建一个方法

public void setFragmentTitle(String title){
        if(!TextUtils.isEmpty(title))
        mTitleText.setText(title);
    }

从您在 onCreateView 中的各个 fragment 访问此方法

((LandingActivity) getActivity()).setFragmentTitle(getActivity().getString(R.string.fragment_title));

1. 如果我使用 getSupportActionBar().setDisplayHomeAsUpEnabled(true) 更改为后退箭头，导航汉堡将继续显示；然后向后箭头打开抽屉但不会返回到最后一个 fragment 。

   在点击android.R.id.home时使用onOptionItemSelected，弹出当前Fragment

2. 按下后退按钮或直接跳转到某个 fragment 时 fragment 状态丢失

   您必须提及需要保留并重新填充的值。

---

public class ActivityABC....{

private String mFName;
private TableSelectFragment mFragment;

   @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        FragmentManager fm = getSupportFragmentManager();

    if (savedInstanceState != null) {

      mFragment=(TableSelectFragment)fm.getFragment(savedInstanceState,"TABLE_FRAGMENT");
      mFName = savedInstanceState.getString("FNAMETAG");

    }else{
      mFragment = new TableSelectFragment();
      fm.beginTransaction().add(R.id.content_frame,mFragment,"TABLE_FRAGMENT").commit();
       }
    }

   @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
       getSupportFragmentManager().putFragment(outState,"TABLE_FRAGMENT",mFragment);
    }
}

在你的 fragment 中

TableSelectFragment{

  ....

   private String mFName;

   @Override
   public void onCreate(@Nullable Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setRetainInstance(true);
    }

    @Override
    public void onSaveInstanceState(@NonNull Bundle outState) {
        outState.putString("FNAMETAG", mFName);
        super.onSaveInstanceState(outState);
    }
}

---

编辑 1:对于 Fragment Title 没有在 BackButton press 中更新

在将 Fragment 添加到 backstack 时，执行以下操作。

在你的父 Activity 中

FragmentManager fragMan = getSupportFragmentManager();
FragmentTransaction fragTrans = fragMan.beginTransaction();
LandingFrag landingFrag = LandingFrag.newInstance();
fragTrans.replace(R.id.landing_view, landingFrag,"LandingFrag");
fragTrans.addToBackStack(null);
fragTrans.commit();
landingFrag.setUserVisibleHint(true);

现在覆盖父 Activity 中的 onBackPressed

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {

            .. POP Fragment Backstack here

            Fragment fragment =  getActiveFragment();
            if(fragment instanceof  LandingFrag)
            {
                    LandingFrag landingFrag = (LandingFrag)fragment;
                    landingFrag.setUserVisibleHint(true);
            }

        }

  public Fragment getActiveFragment() {
        if (getSupportFragmentManager().getBackStackEntryCount() == 0) {
            return null;
        }
        Fragment fragment=null;
        int trackBackValue = 1;//INCREASE OR DECREASE ACCORDING TO YOUR BACK STACK

        try {
            fragment = getSupportFragmentManager().getFragments().get(getSupportFragmentManager().getBackStackEntryCount() - trackBackValue);
        } catch (Exception e) {
        }
        return fragment;

   }

现在在 LandingFrag

public class LandingFrag...
{

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setUserVisibleHint(false);
        .....
    }

    @Override
    public void onViewStateRestored(@Nullable Bundle savedInstanceState) {
        super.onViewStateRestored(savedInstanceState);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
         ................    
          ((LandingActivity) getActivity()).setFragmentTitle("Current Fragment Title");
    }
    @Override
    public void setUserVisibleHint(boolean isVisibleToUser) {
        super.setUserVisibleHint(isVisibleToUser);
        if(isVisibleToUser){
            try {
                ((LandingActivity) getActivity()).setFragmentTitle("Current Fragment Title");
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

}