Question

我对Android很新。我正在制作一个使用Tabs的新应用程序。现在，我想在选项卡中显示不同的片段。

请注意我的MinSDK是Android KitKat 4.4所以我不会使用弃用的方法

我的代码是：

MainActivity.java

public class MainActivity extends ActionBarActivity {
SectionsPagerAdapter mSectionsPagerAdapter;

ViewPager mViewPager;

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

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

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

}


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

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    if(id == R.id.search)
    {
        Toast.makeText(getApplicationContext(),"You tapped on SEARCH !", Toast.LENGTH_LONG).show();
    }

    return super.onOptionsItemSelected(item);
}


/**
 * 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 position) {
        // getItem is called to instantiate the fragment for the given page.
        // Return a PlaceholderFragment (defined as a static inner class below).


        return PlaceholderFragment.newInstance(position + 1);
    }

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

    @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);
        }
        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_1, container, false);

        Button b1 = (Button) rootView.findViewById(R.id.b1);
        b1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getActivity(), "Done", Toast.LENGTH_LONG).show();
            }
        });
        return rootView;
    }
}
}

Fragment_Main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity$PlaceholderFragment">

<EditText
    android:id="@+id/et1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:hint="Enter your Name (Fragment Main"/>

<EditText
    android:id="@+id/et2"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_below="@+id/et1"
    android:hint="Enter your ID (Fragment Main)"/>

<Button
    android:id="@+id/b1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Submit"
    android:layout_below="@+id/et2"/>
</RelativeLayout>

Fragment_1.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context=".MainActivity$FragmentOne">

<Button
    android:id="@+id/b1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Submit"
    android:layout_below="@+id/et2"/>
</RelativeLayout>

我更改了工具：fragment_1.xml中的上下文用于我的测试。我不知道它的作用现在，当用户打开App时，他应该看到Fragment_Main片段。当他滑动下一个标签时，他应该看到fragment_1。

请提供详细帮助，因为我很新。

Answer 1

究竟什么不起作用？

我只能猜测，但你不能在任何地方使用Fragment_Main.xml。您已经将视图寻呼机的位置传递给您的片段，您应该检索它并根据它来扩展布局。片段里面有这样的东西：

private int mFragmentIndex = 0;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        mFragmentIndex = getArguments().getInt(ARG_SECTION_NUMBER);
    }
}

并且在onCreateView中，你应该根据片段索引来扩展不同的布局：

    View rootView;
    if (mFragmentIndex == 1) {
         rootView = inflater.inflate(R.layout.Fragment_Main, container, false);
    } else {
         rootView = inflater.inflate(R.layout.fragment_1, container, false);
    }

无论如何，我建议使用不同的片段，而不是膨胀不同的布局。像这样：

 @Override
public Fragment getItem(int position) {
    if (position == 0) {
        return MainFragment.newInstance();
    } else {
        return SomeOtherFragment.newInstance();
    }

}

具有不同片段的多个选项卡

1 个答案: