标签不显示答案

【问题标题】：Tabs doesn't show标签不显示
【发布时间】：2016-07-10 10:40:33
【问题描述】：

我想在 myActivity 中添加选项卡，当我单击一些选项卡时，会创建并添加片段。但是现在当我单击选项卡时，什么也没发生。标签活动：

public class TabsActivity extends FragmentActivity {

    Fragment directFragmentTab = new Direct();
    Fragment adventuresFragmentTab = new AdventuresFragment();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.tabs_activity);


        TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
        tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
        tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));

        tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
        FragmentManager fragmentManager = getSupportFragmentManager();
        final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
        final ViewPagerAdapter adapter = new ViewPagerAdapter(fragmentManager, tabLayout.getTabCount())
                 {
            @Override
            public int getCount() {
                return 0;
            }

            @Override
            public boolean isViewFromObject(View view, Object object) {
                return false;
            }
        };
        viewPager.setAdapter(adapter);
        viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @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) {

            }
        });
    }
}

ViewPagerAdapter：

public class ViewPagerAdapter extends FragmentStatePagerAdapter {
    int mNumOfTabs;

    public ViewPagerAdapter(FragmentManager fm, int NumOfTabs) {
        super(fm);
        this.mNumOfTabs = NumOfTabs;
    }


    @Override
    public android.support.v4.app.Fragment getItem(int position) {

        switch (position) {
            case 0:
                Direct tab1 = new Direct();
                return tab1;
            case 1:
                AdventuresFragment tab2 = new AdventuresFragment();
                return tab2;


            default:
                return null;
        }
    }

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

我做错了什么？代码编译没有错误，但我错过了一些逻辑。

【问题讨论】：

不确定那里发生了什么，但看起来不正确。最简单的方法是使用setupWithViewPager()，看这里：guides.codepath.com/android/…
检查 public int getCount() { return 0; } 在 viewpager 适配器中。它应该返回计数
它返回一个计数 public int getCount() { return mNumOfTabs; }

标签： android android-layout android-viewpager android-tabs android-sdk-tools

【解决方案1】：

您不应进一步覆盖 ViewPagerAdapter 中的方法。做吧

final ViewPagerAdapter adapter = new ViewPagerAdapter(fragmentManager, tabLayout.getTabCount());

【讨论】：

【解决方案2】：

试试这个我正在使用相同的代码

 final ViewPagerAdapter adapter = new ViewPagerAdapter(fragmentManager, tabLayout.getTabCount())
             {
        @Override
        public int getCount() {
            return 0;
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return false;
        }
    };

替换为

final PagerAdapter adapter = new PagerAdapter(getSupportFragmentManager(), tabLayout.getTabCount());

像这样编辑您的代码

   TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
    tabLayout.addTab(tabLayout.newTab().setText("Tab 1"));
    tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
    tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);

    final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
    final PagerAdapter adapter = new PagerAdapter(getSupportFragmentManager(), tabLayout.getTabCount());
    viewPager.setAdapter(adapter);
    viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
    tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
        @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) {
        }
    });

【讨论】：