如何从底部导航栏移动到活动android

Question

我将其添加到我的应用程序底部导航栏中，但现在的问题是，我想从底部导航栏中的一个按钮移动到活动必须分段才能查看的活动（TabLayout，ViewPager）。当我尝试将其设置为selectedFragment=newmainActivityoderlistfargmant（）时；“显示我”这样的错误。。也是这样，也不管用。。startActivity（新意图（NafMain.this，MainActivityOderLIstFargmant.class））；

我需要移动到其他活动来显示两个（TabLayout、ViewPager）。

此活动我想转到它。。

public class MainActivityOderLIstFargmant extends AppCompatActivity {
    TabLayout tabLayout;
    ViewPager viewPager;
    PageAdapterOrderList pageAdapterOrderList;
    TabItem tabChats;
    TabItem tabCalls;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_mani_order_list);
        tabLayout = findViewById(R.id.tablayout);
        tabChats = findViewById(R.id.tabChats);
        tabCalls = findViewById(R.id.tabCalls);
        viewPager = findViewById(R.id.viewPager);

        pageAdapterOrderList = new PageAdapterOrderList(getSupportFragmentManager(), tabLayout.getTabCount());
        viewPager.setAdapter(pageAdapterOrderList);
        viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));

    }
}

从这里开始

public class NafMaintest extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_naf_main);
        BottomNavigationView bottomNav = findViewById(R.id.bottom_navigation);
            BottomNavigationView bottomNavigationView = (BottomNavigationView) findViewById(R.id.bottom_navigation);
            bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
                @Override
                public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
                    Fragment selectedFragment = null;
                    switch (menuItem.getItemId()) {
                        case R.id.nav_home:
                           selectedFragment = new MainActivityOderLIstFargmant();//I try like that but not work 
                            break;
                        case R.id.nav_favorites:
                            selectedFragment = new FragmentHome();
                            break;
                        case R.id.nav_search:
                            selectedFragment = new FragmentProfile();
                            break;
                        case R.id.nav_s:
                            selectedFragment = new MainActivity();
                            break;
                    }
                    getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                            selectedFragment).commit();
                    return true;

                }
            });

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container,
                    new FragmentHome()).commit();
        }
    }



}

如果有人知道解决方案对我有什么帮助

Answer 1

您试图在开关中实例化MainActivityOderLIstFargmant活动，并将其放入名为selectedFragment的变量中，因此这两种类型都不同（Fragment

要使代码正常工作，可以按如下所示更改开关箱

case R.id.nav_home:
    Intent intent = new Intent(NafMaintest.this, MainActivityOderLIstFargmant.class);
    startActivity(intent);
    return true; // use return to avoid triggering the fragment transaction after the `swtich` block