在 viewpager 中的片段之间打开和导航

Question

我在 Main Activity 中有一个 FrameLayout 和 Navigation Drawer。我正在使用这个 FrameLayout 在 Main Activity 中处理一个片段。在这个片段中，我有 TabLayout 和 ViewPager。现在我想要的是在 ViewPager 片段中单击按钮打开一个新片段。但是应用程序在按钮单击时崩溃。是因为 FrameLayout 在 Main Activity 中，而 Button 在子片段的子片段中吗？我曾尝试在选项卡中使用 FrameLayout，但这意味着我必须为每个选项卡使用 FrameLayouts，而我不希望这样。因此，我们将不胜感激在这方面的任何帮助。另外，如何处理工具栏中的后退箭头单击以返回上一个片段？

public class HomeFragment extends Fragment {

    public static TabLayout tabLayout;
    public static ViewPager viewPager;
    public static int int_items = 2;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.homefragment, container, false);
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        tabLayout = (TabLayout) view.findViewById(R.id.tabs);
        viewPager = (ViewPager) view.findViewById(R.id.viewpager);

        viewPager.setAdapter(new MyAdapter(getChildFragmentManager()));

        tabLayout.post(new Runnable() {
            @Override
            public void run() {
                tabLayout.setupWithViewPager(viewPager);
            }
        });
    }

    class MyAdapter extends FragmentPagerAdapter {

        public MyAdapter(FragmentManager fm) {
            super(fm);
        }

        /**
         * Return fragment with respect to Position .
         */

        @Override
        public Fragment getItem(int position)
        {
            switch (position){
                case 0 : return new TabOne();
                case 1 : return new TabTwo();
            }
            return null;
        }

        @Override
        public int getCount() {

            return int_items;

        }

        /**
         * This method returns the title of the tab according to the position.
         */

        @Override
        public CharSequence getPageTitle(int position) {

            switch (position){
                case 0 :
                    return "ONE";
                case 1 :
                    return "TWO";
            }
            return null;
        }
    }
}

public class TabOne extends Fragment {

    private Button newFrag;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.tabone, container, false);
    }

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        newFrag = (Button)view.findViewById(R.id.button);
        newFrag.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                FragmentTransaction xfragmentTransaction = getChildFragmentManager().beginTransaction();
                xfragmentTransaction.replace(R.id.containerView, new NewFrag()).addToBackStack(null).commit();



            }
        });
    }
}

public class MainActivity extends AppCompatActivity {

    DrawerLayout myDrawerLayout;
    NavigationView myNavigationView;
    Toolbar toolbar;
    ActionBarDrawerToggle mDrawerToggle;
    FragmentManager myFragmentManager;
    FragmentTransaction myFragmentTransaction;

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

        myDrawerLayout = (DrawerLayout) findViewById(R.id.drawerLayout);
        myNavigationView = (NavigationView) findViewById(R.id.nav_drawer) ;

        myFragmentManager = getSupportFragmentManager();
        myFragmentTransaction = myFragmentManager.beginTransaction();
        myFragmentTransaction.replace(R.id.containerView, new HomeFragment()).commit();

        myNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(MenuItem selectedMenuItem) {
                myDrawerLayout.closeDrawers();


                if (selectedMenuItem.getItemId() == R.id.nav_profile) {
                    FragmentTransaction fragmentTransaction = myFragmentManager.beginTransaction();
                    fragmentTransaction.replace(R.id.containerView, new ProfileFragment()).addToBackStack(null).commit();

                }

                if (selectedMenuItem.getItemId() == R.id.nav_history) {
                    FragmentTransaction xfragmentTransaction = myFragmentManager.beginTransaction();
                    xfragmentTransaction.replace(R.id.containerView, new HistoryFragment()).addToBackStack(null).commit();
                }

                return false;
            }

        });

        toolbar = (Toolbar)findViewById(R.id.toolbar);
        mDrawerToggle = new ActionBarDrawerToggle(this, myDrawerLayout, toolbar, R.string.app_name, R.string.app_name);
        myDrawerLayout.setDrawerListener(mDrawerToggle);
        mDrawerToggle.syncState();

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                onBackPressed();
                break;
            default:
                break;
        }

        return super.onOptionsItemSelected(item);
    }
}

FATAL EXCEPTION: main
Process: com.sam.demonavigation, PID: 8523
java.lang.IllegalArgumentException: No view found for id 0x7f0c006b (com.sam.demonavigation:id/containerView) for fragment HistoryFragment{42016928 #0 id=0x7f0c006b}
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1059)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1252)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:742)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1617)
at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:517)
at android.os.Handler.handleCallback(Handler.java:808)
at android.os.Handler.dispatchMessage(Handler.java:103)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:5388)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:655)
at dalvik.system.NativeStart.main(Native Method)

Answer 1

这个link 被证明非常有用。使用链接中提到的方法，我可以在主活动中使用 FrameLayout 打开任何片段

// This is the button click event in one of the TabLayout fragment

newFrag.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Fragment var1 = new NewFrag();
                ((MainActivity)getActivity()).replaceFragment(var1);

            }
});

// Add this method in MainActivity

 public void replaceFragment(Fragment fragment){
        FragmentTransaction t = getSupportFragmentManager().beginTransaction();
        t.replace(R.id.containerView, fragment).addToBackStack(null);
        t.commit();
 }

.

Answer 2

1-Create ViewPager object

      ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
            viewPager.setOffscreenPageLimit(3);
            setupViewPager(viewPager);

2-then add Custom FragmentPagerAdapter

 ViewPagerAdapter adapter = new ViewPagerAdapter(this);
 adapter.addFrag(new Fragment1(), "Item1");
 adapter.addFrag(new Fragment2(), "Item2");
 adapter.addFrag(new Fragment3(), "Item3");
 viewPager.setAdapter(adapter);

3-After that write custom adapter definition

class ViewPagerAdapter extends FragmentPagerAdapter {

    private final List<Fragment> mFragmentList = new ArrayList<>();
    private final List<String> mFragmentTitleList = new ArrayList<>();

    public ViewPagerAdapter(FragmentManager manager) {
        super(manager);
    }

    @Override
    public Fragment getItem(int position) {
        return mFragmentList.get(position);
    }

    @Override
    public int getCount() {
        return mFragmentList.size();
    }

    public void addFrag(Fragment fragment, String title) {
        mFragmentList.add(fragment);
        mFragmentTitleList.add(title);
    }

    @Override
    public CharSequence getPageTitle(int position) {
        return mFragmentTitleList.get(position);
    }