在微调器动作上更新 viewepager

Question

我有一个带有片段的 viewpager，我想在单击微调器的某个项目后用新片段更新我的 viewpager。现在，无论微调器的值是多少，适配器都不会自行更新。这是我到目前为止所做的：

public class MainActivity extends FragmentActivity {
private ViewPager pager;
Spinner spinner;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main); 
    pager = (ViewPager) findViewById(R.id.viewPager);
    spinner = (Spinner)  findViewById(R.id.spinner);

    ArrayAdapter<CharSequence> stringArrayAdapter = ArrayAdapter.createFromResource(this,
    R.array.language, android.R.layout.simple_spinner_item);
    stringArrayAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(stringArrayAdapter);

    spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
        @Override
        public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {

        if(spinner.getSelectedItem().toString().equals("Frensh"))
        {
         pager.setAdapter(new MyPagerAdapter(getSupportFragmentManager()));
         pager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
             @Override
             public void onPageSelected(int position) {
                 invalidateOptionsMenu();
             }
         });
        }

        else if(spinner.getSelectedItem().toString().equals("English"))
        {
         pager.setAdapter(new MyPagerAdapter2(getSupportFragmentManager()));
         pager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
             @Override
             public void onPageSelected(int position) {
                 invalidateOptionsMenu();
             }
         });

        }
        }
        }
        @Override
        public void onNothingSelected(AdapterView<?> parentView) {
            // your code here
        }
        });
}

public boolean onCreateOptionsMenu(Menu menu) {
    super.onCreateOptionsMenu(menu);
    getMenuInflater().inflate(R.menu.activity_screen_slide, menu);

    menu.findItem(R.id.action_previous).setEnabled(pager.getCurrentItem() > 0);
    MenuItem item = menu.add(Menu.NONE, R.id.action_next, Menu.NONE,
            (pager.getCurrentItem() == pager.getAdapter().getCount() - 1)
                    ? R.string.action_finish
                    : R.string.action_next);
    item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM | MenuItem.SHOW_AS_ACTION_WITH_TEXT);
    return true;
}

public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            NavUtils.navigateUpTo(this, new Intent(this, MainActivity.class));
            return true;
        case R.id.action_previous:
            pager.setCurrentItem(pager.getCurrentItem() - 1);
            return true;
        case R.id.action_next:
            pager.setCurrentItem(pager.getCurrentItem() + 1);
            return true;
    }

    return super.onOptionsItemSelected(item);
}

这是包含我的法语片段的class：

public static class MyPagerAdapter extends FragmentPagerAdapter {

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

    @Override
    public Fragment getItem(int pos) {

        switch(pos) {
        case 0: return Fr_FirstFragment.newInstance("Page : 1");
        case 1: return Fr_SecondFragment.newInstance("Page : 2");
        case 2: return Fr_ThirdFragment.newInstance("Page : 3");
        case 3: return Fr_FourthFragment.newInstance("Page : 4");
        default: return null;
        }
    }

    @Override
    public int getCount() {
        return 4;
    }         
}

这是包含我的英语片段的class：

public static class MyPagerAdapter2 extends FragmentPagerAdapter {

    public MyPagerAdapter2(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int pos) {

        switch(pos) {
        case 0: return En_FirstFragment.newInstance("Page : 1");
        case 1: return En_SecondFragment.newInstance("Page : 2");
        case 2: return En_ThirdFragment.newInstance("Page : 3");
        case 3: return En_FourthFragment.newInstance("Page : 4");
        default: return null;
        }
    }

    @Override
    public int getCount() {
        return 4;
    }      
}

Answer 1

除了一件事，您的整体代码看起来还不错。您选择使用 Fragment Pager Adapter 并非出于此目的。如果你想动态更新Pager和Fragments里面的Data，你应该使用FragmentStatePagerAdapter，其余的应该是一样的。

在微调器动作上更新 viewepager

Update a viewepager on spinner action

android

android-fragments

android-viewpager