如何使用带有片段的底部导航视图？

时间：2020-01-16 12:04:39

标签： android android-fragments stack bottomnavigationview fragment-lifecycle

我正在学习Android编程。我在我的应用程序中使用BottomNavigationView使用片段过渡。以下是我遇到的问题。切换选项卡时，每次移动时，选项卡上的代码都会重新执行。某些选项卡对问题的响应非常慢。我要做的只是运行一次，并像活动的onCreate一样保持存储。我也想拥有一堆以前执行过的片段。附件是我的代码的一部分。 句子可能不太流畅，但希望您能理解。我可以随时为您服务。

activity_main.xml 

 <?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

     <FrameLayout
         android:id="@+id/frame_layout"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:layout_marginBottom="?attr/actionBarSize"/>


        <com.google.android.material.bottomnavigation.BottomNavigationView
            android:id="@+id/bottom_navigation_view"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_gravity="bottom"
            android:background="?android:attr/windowBackground"
            app:menu="@menu/menu_bottom"
            app:labelVisibilityMode="unlabeled"
            />


</androidx.coordinatorlayout.widget.CoordinatorLayout>

MainActivity.java 

public class MainActivity extends AppCompatActivity {
    private FragmentManager fragmentManager = getSupportFragmentManager();

    private menu_1 menu1Fragment = new menu_1();
    private menu_2 menu2Fragment = new menu_2();
    private menu_5 menu5Fragment = new menu_5();

    private fragment_menu_4_like fragment_menu_4_like = new fragment_menu_4_like();

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

        BottomNavigationView bottomNavigationView = findViewById(R.id.bottom_navigation_view);

        FragmentTransaction transaction = fragmentManager.beginTransaction();


        transaction.add(R.id.frame_layout, menu1Fragment).commitAllowingStateLoss();


        bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                FragmentTransaction transaction = fragmentManager.beginTransaction();
                switch (item.getItemId()) {
                    case R.id.navigation_menu1: {
                        transaction.replace(R.id.frame_layout, menu1Fragment).commitAllowingStateLoss();
                        break;
                    }
                    case R.id.navigation_menu2: {
                        transaction.replace(R.id.frame_layout, menu2Fragment).commitAllowingStateLoss();
                        break;
                    }
                    case R.id.navigation_menu3: {
                        transaction.replace(R.id.frame_layout,  menu5Fragment).commitAllowingStateLoss();
                        break;
                    }
                    case R.id.navigation_menu4: {
                        transaction.replace(R.id.frame_layout, fragment_menu_4_like).commitAllowingStateLoss();
                        break;
                    }


                    case R.id.navigation_menu5: {
                        transaction.replace(R.id.frame_layout,  menu5Fragment).commitAllowingStateLoss();
                        break;
                    }
                }

                return true;
            }
        });
    }

    public void replaceFragment(Fragment fragment) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.replace(R.id.frame_layout, fragment).commit();     
    }

    }

fragment_menu_1.xml 

<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context=".menu_1">

    <com.google.android.material.appbar.AppBarLayout
        android:id="@+id/missionDetailAppbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fitsSystemWindows="true">

        <com.google.android.material.appbar.CollapsingToolbarLayout
            android:id="@+id/missionDetailCollapsingToolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:fitsSystemWindows="true"
            android:background="#FFFFFF"
            app:layout_scrollFlags="scroll|exitUntilCollapsed"
            >
            <LinearLayout
                android:id="@+id/linearLayout"
                android:layout_width="match_parent"
                android:layout_height="60dp"
                android:gravity="center"
                android:orientation="horizontal"
                android:weightSum="10"
                app:layout_behavior="@string/appbar_scrolling_view_behavior"
                >
                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="0.2" />

                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:gravity="center"
                    android:padding="10dp"
                    android:src="@drawable/supermarket" />

                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="0.5" />

                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:gravity="center"
                    android:padding="10dp"
                    android:src="@drawable/password" />

                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="0.5" />

                <TextView
                    android:id="@+id/textView"
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="3"
                    android:text="FitMe"
                    android:gravity="center"
                    android:textColor="#000000"
                    android:textSize="35dp" />

                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="0.5" />

                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="0.2" />

                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:gravity="center"
                    android:padding="10dp"
                    android:src="@drawable/search" />

                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="0.5" />

                <ImageView
                    android:layout_width="0dp"
                    android:layout_height="match_parent"
                    android:layout_weight="1"
                    android:padding="10dp"
                    android:src="@drawable/menu" />




            </LinearLayout>


        </com.google.android.material.appbar.CollapsingToolbarLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
        <ImageView
            android:layout_width="match_parent"
            android:layout_height="80dp"
            android:minHeight="80dp"
            android:src="@drawable/test123123"
            android:scaleType="fitXY"
            android:contentDescription="TODO" />
        </LinearLayout>
    </com.google.android.material.appbar.AppBarLayout>


    <androidx.core.widget.NestedScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:overScrollMode="never"
        app:layout_behavior="@string/appbar_scrolling_view_behavior">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical"
            >

            <androidx.recyclerview.widget.RecyclerView
                android:id="@+id/test_recyclerview"
                android:layout_width="match_parent"
                android:layout_height="450dp"
                android:layout_marginBottom="15dp" />

            <androidx.recyclerview.widget.RecyclerView
                android:id="@+id/main.scrollview.recyclerview"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                >
            </androidx.recyclerview.widget.RecyclerView>
        </LinearLayout>

    </androidx.core.widget.NestedScrollView>

</androidx.coordinatorlayout.widget.CoordinatorLayout>

menu_1.java 

public class menu_1 extends Fragment {

    RecyclerView test_image_recyclerview;

    main_slide_image_recyclerview_adapter adapter;

    ArrayList<recycerlveiw_array> array;

    RecyclerView.LayoutManager layoutManager;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

        return inflater.inflate(R.layout.fragment_menu_1, container, false);


    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        test_image_recyclerview = (RecyclerView) view.findViewById(R.id.test_recyclerview);

        array = new ArrayList<>();

        adapter = new main_slide_image_recyclerview_adapter(getActivity(), array);


        layoutManager = new LinearLayoutManager(getActivity());

        ((LinearLayoutManager) layoutManager).setOrientation(LinearLayoutManager.HORIZONTAL);

        SnapHelper snapHelper = new PagerSnapHelper();

        test_image_recyclerview.setLayoutManager(layoutManager);
        snapHelper.attachToRecyclerView(test_image_recyclerview);

        test_image_recyclerview.setAdapter(adapter);

        Uri uri = Uri.parse("android.resource://"+"com.example.testfitmelayouttest"+"/drawable/image2");
        Uri uri2 = Uri.parse("android.resource://"+"com.example.testfitmelayouttest"+"/drawable/testimage_slide_1");
        Uri uri3 = Uri.parse("android.resource://"+"com.example.testfitmelayouttest"+"/drawable/testimage_slide_2");
        Uri uri4 = Uri.parse("android.resource://"+"com.example.testfitmelayouttest"+"/drawable/testimage_slide_3");

        recycerlveiw_array array1 = new recycerlveiw_array(uri);
        recycerlveiw_array array2 = new recycerlveiw_array(uri2);
        recycerlveiw_array array3 = new recycerlveiw_array(uri3);
        recycerlveiw_array array4 = new recycerlveiw_array(uri4);


        array.add(array1);
        array.add(array3);
        array.add(array2);
        array.add(array4);

        final List<String> testStrings = new ArrayList<>();
        for(int i = 0; i < 100; i++) {
            testStrings.add(i + " 번째 item");
        }
        RecyclerView recyclerView = view.findViewById(R.id.main_scrollview_recyclerview);
        recyclerView.setAdapter(new RecyclerView.Adapter<TestViewHolder>() {
            @Override
            public TestViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
                View view = View.inflate(getActivity(), android.R.layout.simple_list_item_1, null);
                return new TestViewHolder(view);
            }

            @Override
            public void onBindViewHolder(TestViewHolder holder, int position) {
                holder.textView.setText(testStrings.get(position));
            }
            public int getItemCount() {
                return testStrings.size();
            }
        });
        recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    }

    public static class TestViewHolder extends RecyclerView.ViewHolder {
        public TextView textView;
        public TestViewHolder(View itemView) {
            super(itemView);
            textView = itemView.findViewById(android.R.id.text1);
        }

        @Override
        public String toString() {
            return super.toString();
        }
    }

}

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