Android 我想在使用滑动选项卡时管理工具栏文本

我在一个活动中有五个可以滑动的选项卡。滑动选项卡时，工具栏文本需要相应更改。为此，我使用了从片段到活动调用该方法的接口，但它不能正常工作。

我假设您希望根据所选选项卡更改工具栏的标题。为此，您可以尝试使用android支持设计库：

例如：

public class MainActivity extends AppCompatActivity implements TabLayout.OnTabSelectedListener{


    TabLayout tabs;
    ViewPager viewPager;
    TabsPagerAdapter adapter;
    Toolbar toolbar;
    CharSequence Titles[] = {"one", "two", "three"};
    int Numboftabs = 3;

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    toolbar = (Toolbar) findViewById(R.id.tool_bar);
    if (toolbar != null) {
        toolbar.setTitle(R.string.app_name);
        setSupportActionBar(toolbar);

    }

    adapter = new TabsPagerAdapter(getSupportFragmentManager(), Titles, Numboftabs);
    // Assigning ViewPager View and setting the adapter
    viewPager = (ViewPager) findViewById(R.id.pager);
    viewPager.setAdapter(adapter);
    // Assiging the Sliding Tab Layout View
    tabs = (TabLayout) findViewById(R.id.tabs);
    tabs.setupWithViewPager(viewPager);
    tabs.setTabGravity(TabLayout.GRAVITY_FILL);
    tabs.setOnTabSelectedListener(this);
    tabs.setVisibility(View.GONE);
}
 @Override
public void onTabSelected(TabLayout.Tab tab) {
    switch(tab.getPosition()) {

        case 0:
            viewPager.setCurrentItem(0);
            toolbar.setTitle("Your Title one");
            break;
        case 1:
            viewPager.setCurrentItem(1);
            toolbar.setTitle("Your Title two");
            break;
        case 2:
            viewPager.setCurrentItem(2);
            toolbar.setTitle("Your title three");
            break;
        default:

            viewPager.setCurrentItem(tab.getPosition());
            toolbar.setTitle("Your APP NAME");
            break;
    }

}

@Override
public void onTabUnselected(TabLayout.Tab tab) {

}

@Override
public void onTabReselected(TabLayout.Tab tab) {

}
}

---

我是用下面的方式做的

viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            if (position == 0) {
                toobar.setTitle("one");
            } else if (position == 1) {
                toobar.setTitle("two");

            } else if (position == 2) {
                toobar.setTitle("three");
            } else if (position == 3) {
                toobar.setTitle("four");
            } else if (position == 4) {
                toobar.setTitle("five");
            }
        }