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如何在滚动时更新选项卡的值

tabs android

chinmay · 技术社区 · 7 年前

我已经在android中实现了选项卡布局。我有3个选项卡设置,时钟,丢失的设备。滚动时,会更新选项卡的内容,但不会更新标题。但如果我选择任何选项卡标题,就会显示内容。当我启动应用程序时,它会显示3个选项卡。假设当前突出显示的选项卡是时钟。当我向右滚动时,将显示设置选项卡的内容,但当前突出显示的选项卡仍然是时钟。它应该是根据我的需要设置。

我的代码是这是主要活动->

public class MainActivity extends AppCompatActivity implements TabLayout.OnTabSelectedListener{

    //This is our tablayout
    private TabLayout tabLayout;

    //This is our viewPager
    private ViewPager viewPager;

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

        //Adding toolbar to the activity
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        //Initializing the tablayout
        tabLayout = (TabLayout) findViewById(R.id.tabLayout);

        //Adding the tabs using addTab() method
        tabLayout.addTab(tabLayout.newTab().setText("clock"));
        tabLayout.addTab(tabLayout.newTab().setText("settings"));
        tabLayout.addTab(tabLayout.newTab().setText("lost devices"));
        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

        //Initializing viewPager
        viewPager = (ViewPager) findViewById(R.id.pager);

        //Creating our pager adapter
        Pager adapter = new Pager(getSupportFragmentManager(), tabLayout.getTabCount());

        //Adding adapter to pager
        viewPager.setAdapter(adapter);

        //Adding onTabSelectedListener to swipe views
        tabLayout.setOnTabSelectedListener(this);
    }

    @Override
    public void onTabSelected(TabLayout.Tab tab) {
        viewPager.setCurrentItem(tab.getPosition());
    }

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

    }

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

    }
}

寻呼机->

public class Pager extends FragmentStatePagerAdapter {

    //integer to count number of tabs
    int tabCount;

    //Constructor to the class
    public Pager(FragmentManager fm, int tabCount) {
        super(fm);
        //Initializing tab count
        this.tabCount= tabCount;
    }

    //Overriding method getItem
    @Override
    public Fragment getItem(int position) {
        //Returning the current tabs
        switch (position) {
            case 0:
                clock tab1 = new clock();
                return tab1;
            case 1:
                settings tab2 = new settings();
                return tab2;
            case 2:
                map tab3 = new map();
                return tab3;
            default:
                return null;
        }
    }

    //Overriden method getCount to get the number of tabs
    @Override
    public int getCount() {
        return tabCount;
    }
}

2 回复 | 直到 7 年前

Truong Giang Dam 7 年前

这是由于TabLayout和ViewPager是相互独立的。您需要更新他们的状态,以防其中一人进行更改。选择选项卡后,您已完成更新ViewPager状态。但反之亦然,当ViewPager滚动时,您需要更新Tablayout。

为viewPager添加侦听器: viewPager.addOnPageChangeListener(this); . 这将需要您实现一些方法。

@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
     // don't use in that's case
}

@Override
public void onPageSelected(int position) {
    // update Tablayout here
    TabLayout.Tab tab = tabLayout.getTabAt(position);
    if (tab != null) {
       tab.select();
    }
}

@Override
public void onPageScrollStateChanged(int state) {
   // don't use in that's case
}

如果不再使用侦听器,请不要忘记将其删除
```
viewPager.removeOnPageChangeListener(this);
```

希望对你有帮助!

-1

Abhishek Singh 7 年前

您已经使用选项卡布局设置了viewpager。添加此

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

    //Adding adapter to pager
    viewPager.setAdapter(adapter);
    tabLayout.setupWithViewPager(viewPager);
    //Adding onTabSelectedListener to swipe views
    tabLayout.setOnTabSelectedListener(this);
}