在Tabbed Activity中使用ViewPager实现OnFragmentInteractionListener

Question

使用Android Studio的选项卡式活动和导航样式：选项卡式活动（ViewPager）创建可滑动的导航选项卡。开始弄清楚如何为每个标签编辑片段，所以我添加了......

        @Override
    public Fragment getItem(int i) {
        switch (i) {
            case 0:
                return new YourFragmentClass1();
            case 1:
                return new YourFragmentClass2();
            case 2:
                return new YourFragmentClass3();
            case 3:
                return new YourFragmentClass4();
        }
        return null;

    }

...并创建了4个片段类。当我去运行它时，我关闭了一个力，告诉我需要在大约39个位置实现OnFragmentInteractionListener。我还没有找到解决问题的任何内容，而且我从哪里开始有点不知所措。我的主要活动中是否存在需要首先解决的问题，还是存在于每个片段活动中？

这是我的主要活动代码和我的LogCat：

public class MyActivity extends Activity implements ActionBar.TabListener {

/**
 * The {@link android.support.v4.view.PagerAdapter} that will provide
 * fragments for each of the sections. We use a
 * {@link FragmentPagerAdapter} derivative, which will keep every
 * loaded fragment in memory. If this becomes too memory intensive, it
 * may be best to switch to a
 * {@link android.support.v13.app.FragmentStatePagerAdapter}.
 */
SectionsPagerAdapter mSectionsPagerAdapter;

/**
 * The {@link ViewPager} that will host the section contents.
 */
ViewPager mViewPager;

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

    // Set up the action bar.
    final ActionBar actionBar = getActionBar();
    actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Create the adapter that will return a fragment for each of the three
    // primary sections of the activity.
    mSectionsPagerAdapter = new SectionsPagerAdapter(getFragmentManager());

    // Set up the ViewPager with the sections adapter.
    mViewPager = (ViewPager) findViewById(R.id.pager);
    mViewPager.setAdapter(mSectionsPagerAdapter);

    // When swiping between different sections, select the corresponding
    // tab. We can also use ActionBar.Tab#select() to do this if we have
    // a reference to the Tab.
    mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
        @Override
        public void onPageSelected(int position) {
            actionBar.setSelectedNavigationItem(position);
        }
    });

    // For each of the sections in the app, add a tab to the action bar.
    for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
        // Create a tab with text corresponding to the page title defined by
        // the adapter. Also specify this Activity object, which implements
        // the TabListener interface, as the callback (listener) for when
        // this tab is selected.
        actionBar.addTab(
                actionBar.newTab()
                        .setText(mSectionsPagerAdapter.getPageTitle(i))
                        .setTabListener(this));
    }
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.my, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
}

@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
    // When the given tab is selected, switch to the corresponding page in
    // the ViewPager.
    mViewPager.setCurrentItem(tab.getPosition());
}

@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}

@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}

/**
 * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
 * one of the sections/tabs/pages.
 */
public class SectionsPagerAdapter extends FragmentPagerAdapter {

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

    @Override
    public Fragment getItem(int i) {
        switch (i) {
            case 0:
                return new YourFragmentClass1();
            case 1:
                return new YourFragmentClass2();
            case 2:
                return new YourFragmentClass3();
            case 3:
                return new YourFragmentClass4();
        }
        return null;

    }

    @Override
    public int getCount() {
        // Show 3 total pages.
        return 4;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        Locale l = Locale.getDefault();
        switch (position) {
            case 0:
                return getString(R.string.title_section1).toUpperCase(l);
            case 1:
                return getString(R.string.title_section2).toUpperCase(l);
            case 2:
                return getString(R.string.title_section3).toUpperCase(l);
            case 3:
                return getString(R.string.title_section4).toUpperCase(l);
        }
        return null;
    }
}

/**
 * A placeholder fragment containing a simple view.
 */
public static class PlaceholderFragment extends Fragment {
    /**
     * The fragment argument representing the section number for this
     * fragment.
     */
    private static final String ARG_SECTION_NUMBER = "section_number";

    /**
     * Returns a new instance of this fragment for the given section
     * number.
     */
    public static PlaceholderFragment newInstance(int sectionNumber) {
        PlaceholderFragment fragment = new PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    public PlaceholderFragment() {
    }

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

}



java.lang.ClassCastException: com.nicholasthompson.tabtest.MyActivity@420264e8 must implement OnFragmentInteractionListener
        at com.nicholasthompson.tabtest.YourFragmentClass1.onAttach(YourFragmentClass1.java:84)
        at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:849)
        at android.app.FragmentManagerImpl.performPendingDeferredStart(FragmentManager.java:785)
        at android.app.Fragment.setUserVisibleHint(Fragment.java:997)
        at android.support.v13.app.FragmentCompatICSMR1.setUserVisibleHint(FragmentCompatICSMR1.java:23)
        at android.support.v13.app.FragmentCompat$ICSMR1FragmentCompatImpl.setUserVisibleHint(FragmentCompat.java:48)
        at android.support.v13.app.FragmentCompat.setUserVisibleHint(FragmentCompat.java:76)
        at android.support.v13.app.FragmentPagerAdapter.setPrimaryItem(FragmentPagerAdapter.java:134)
        at android.support.v4.view.ViewPager.populate(ViewPager.java:1066)
        at android.support.v4.view.ViewPager.populate(ViewPager.java:914)
        at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1436)
        at android.view.View.measure(View.java:16617)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5145)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
        at android.view.View.measure(View.java:16617)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5145)
        at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327)
        at android.view.View.measure(View.java:16617)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5145)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
        at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291)
        at android.view.View.measure(View.java:16617)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2061)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1188)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1397)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1075)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5878)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
        at android.view.Choreographer.doCallbacks(Choreographer.java:574)
        at android.view.Choreographer.doFrame(Choreographer.java:544)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
        at android.os.Handler.handleCallback(Handler.java:733)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:136)
        at android.app.ActivityThread.main(ActivityThread.java:5086)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:515)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
        at dalvik.system.NativeStart.main(Native Method)

Answer 1

您需要在托管片段的每个活动中实现onFragmentInteractionListener。每个片段在由向导创建时，底部都有一个必须使用的接口。在该界面中，您可以定义与片段相关的任何方法。

请参阅http://developer.android.com/training/basics/fragments/communicating.html#Implement

我更喜欢定义一个接口，并且让所有片段或一组片段使用该接口。否则，您最终可能会遇到一个活动，该活动被强制实现X个接口，其中X是您创建的碎片数。