Question

我有一个带Tablayout的主活动，其中包含3个片段。主要活动中的FAB位于所有片段的顶部，作为我的滑动。我需要创建一个界面，以便在单击FAB时，我的ViewPager会收到警报并执行某个操作。有谁知道如何创建这个监听器？

监听器应该只返回一个布尔值，表示点击了Fab。

我在主要活动中添加了一个界面，但我不确定如何利用它并将其连接到我的ViewPagerAdapter类？

这是我的主要活动：

public class MainActivity extends AppCompatActivity {
private ViewPager viewPager;
private ArrayList<Fragment> fragments = new ArrayList<>();
private ArrayList<String> titles = new ArrayList<>();

//MY LISTENER....
private static SwitchFragmentsListener switchFragsListener;

public static interface SwitchFragmentsListener{
    public void doISwitch(boolean change);
}

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

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    CollapsingToolbarLayout collapsingToolbarLayout = (CollapsingToolbarLayout)findViewById(R.id.collapsing_toolbar);
    setSupportActionBar(toolbar);

    fragments.addAll(Arrays.asList(new Tasks(),new Calendar(),new Contacts()));
    titles.addAll(Arrays.asList(getResources().getString(R.string.fragment_task_title),
            getResources().getString(R.string.fragment_cal_title),getResources().getString(R.string.fragment_contacts_title)));
    TabLayout tabLayout = (TabLayout)findViewById(R.id.tabs);

    final FloatingActionButton fab = (FloatingActionButton)findViewById(R.id.fab);
    fab.hide();

    viewPager = (ViewPager)findViewById(R.id.container);
    ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager(),fragments,titles);
    viewPager.setAdapter(viewPagerAdapter);
    viewPager.setCurrentItem(1);
    viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

        }

        @Override
        public void onPageSelected(int position) {
            if (position == 1) {
                fab.hide();
            }else {
                fab.show();
            }

        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }
    });
    tabLayout.setupWithViewPager(viewPager);

    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            fabAction();
        }
    });

    if (savedInstanceState==null){
        if (getSupportActionBar()!=null){
            getSupportActionBar().setDisplayShowTitleEnabled(true);
        }
    }
}

public interface FragChangeListener{
    public void doIChange(boolean change);
}


public void fabAction(){
    int current = viewPager.getCurrentItem();

    switch (current){
        case 0:{
            //NEED TO IMPLEMENT LISTENER HERE
            break;
        }
        case 2:{
            Toast.makeText(this, "IN TAB 3", Toast.LENGTH_LONG).show();
            break;
        }
    }
}}

和我的ViewPagerAdapter

public class ViewPagerAdapter extends FragmentPagerAdapter {
ArrayList<Fragment> fragments;
ArrayList<String> titles;
private Fragment mFragmentAtPos0;
private FragmentManager fragManager;

//NEED TO IMPLEMENT THE LISTENER IN THIS CLASS TELLING ME THAT THE BUTTON WAS CLICKED IN MAIN ACTIVITY
public ViewPagerAdapter(FragmentManager fm, ArrayList<Fragment> fragments, ArrayList<String>titles) {
    super(fm);
    this.fragments = fragments;
    this.titles = titles;
    fragManager = fm;

}

@Override
public Fragment getItem(int position) {
    if (position == 0)
    {

        mFragmentAtPos0 = new AddContact();
        fragManager.beginTransaction().replace(R.id.container,mFragmentAtPos0).commit();
        notifyDataSetChanged();
        return mFragmentAtPos0;
    }else{
        return fragments.get(position);

    }

}

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

@Override
public CharSequence getPageTitle(int position) {

    return titles.get(position);
}

@Override
public int getItemPosition(Object object)
{
    if (object instanceof Tasks && mFragmentAtPos0 instanceof AddContact)
        return POSITION_NONE;
    return POSITION_UNCHANGED;
}

}

Answer 1

单击FAB时，我的ViewPager会收到警报并执行某些行动

我认为在这种情况下你不需要创建监听器。您可以检测单击FAB并将其直接传递给适配器。在你的适配器中，只需创建一个方法来获取FAB的动作。

在ViewPagerAdapter中，创建方法

public void clickFAB() {
    // your code here

}

并在SwitchFragmentsListener中，只需拨打电话：

ViewPagerAdapter viewPagerAdapter;

public void fabAction(){
    int current = viewPager.getCurrentItem();

    switch (current){
        case 0:{
            //NEED TO IMPLEMENT LISTENER HERE
            viewPagerAdapter.clickFAB();
            break;
        }
        case 2:{
            Toast.makeText(this, "IN TAB 3", Toast.LENGTH_LONG).show();
            break;
        }
    }
}}

使用ViewPager实现监听器

1 个答案: