如何在底部导航活动中显示另一个视图？

Question

我想知道显示View 而不是最简单的方法是什么 mTextMessage.setText(R.string.title_home); 在底部导航活动中？

public class MainActivity extends AppCompatActivity {

    private TextView mTextMessage;

    private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {

        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            switch (item.getItemId()) {
                case R.id.navigation_home:
                    // How to display anotherView here?
                    mTextMessage.setText(R.string.title_home);
                    return true;
                case R.id.navigation_dashboard:
                    mTextMessage.setText(R.string.title_dashboard);
                    return true;
                case R.id.navigation_notifications:
                    mTextMessage.setText(R.string.title_notifications);
                    return true;
            }
            return false;
        }
    };

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

        mTextMessage = (TextView) findViewById(R.id.message);
        BottomNavigationView navigation = (BottomNavigationView) findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
    }

}

Answer 1

我在这里找到了很好的解决方案Start fragment in BottomNavigationView

我的工作代码如下

MainActivity

公共类 MainActivity 扩展 AppCompatActivity {

  private BottomNavigationView.OnNavigationItemSelectedListener mOnNavigationItemSelectedListener
            = new BottomNavigationView.OnNavigationItemSelectedListener() {

        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {


            FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
            switch (item.getItemId()) {
                case R.id.navigation_home:

                    FragmentOne selectedFragment1 = new FragmentOne();
                    transaction.replace(R.id.fragmentContainer, selectedFragment1);
                     break;
                case R.id.navigation_dashboard:


                    FragmentTwo selectedFragment2 = new FragmentTwo();
                    transaction.replace(R.id.fragmentContainer, selectedFragment2);
                    break;
                case R.id.navigation_notifications:

                    FragmentThree selectedFragment3 = new FragmentThree();
                    transaction.replace(R.id.fragmentContainer, selectedFragment3);
                    break;
            }

            transaction.commit();
            return true;
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        BottomNavigationView navigation = findViewById(R.id.navigation);
        navigation.setOnNavigationItemSelectedListener(mOnNavigationItemSelectedListener);
        navigation.setSelectedItemId(R.id.navigation_home);
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout  xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="android.apps.myapp.gpsmegatracker.MainActivity"
    android:orientation="vertical">

    <FrameLayout
        android:id="@+id/fragmentContainer"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"/>

    <android.support.design.widget.BottomNavigationView
        android:id="@+id/navigation"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom"
        android:background="?android:attr/windowBackground"
        app:menu="@menu/navigation" /> 
</LinearLayout>

片段类相同

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;


public class FragmentOne extends Fragment {
    public FragmentOne() {
    }

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

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

fragment_fragment_one.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".FragmentOne">



    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button1" />

</FrameLayout>