Question

当我仅创建BottomNavigationView时，它运行良好。但是将BottomNavigationView与Fragment结合使用会出现问题。问题是片段变化很好，但是BottomNavigationView菜单固定在第一个菜单上。

我需要在哪里设置编码/字符集？（对不起，我的英语不好...）

package com.example.ui;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import com.google.android.material.bottomnavigation.BottomNavigationView;

public class HomeActivity extends AppCompatActivity implements View.OnClickListener{

    private FragmentManager fragmentManager = getSupportFragmentManager();
    private menu1Fragment menu1Fragment = new menu1Fragment();
    private menu2Fragment menu2Fragment = new menu2Fragment();
    private menu3Fragment menu3Fragment = new menu3Fragment();
    private menu4Fragment menu4Fragment = new menu4Fragment();

    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        getSupportActionBar().setIcon(R.drawable.logo);
        getSupportActionBar().setDisplayShowHomeEnabled(true);
        setContentView(R.layout.activity_home);

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


        FragmentTransaction transaction = fragmentManager.beginTransaction();
        transaction.replace(R.id.frame_home, menu1Fragment).commitAllowingStateLoss();


        bottomNavigationView.setOnNavigationItemSelectedListener(new ItemSelectedListener());
    }

    class ItemSelectedListener implements BottomNavigationView.OnNavigationItemSelectedListener {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
            FragmentTransaction transaction = fragmentManager.beginTransaction();

            switch (menuItem.getItemId()) {
                case R.id.navigation_menu1:
                    transaction.replace(R.id.frame_home, menu1Fragment).commitAllowingStateLoss();
                    break;
                case R.id.navigation_menu2:
                    transaction.replace(R.id.frame_home, menu2Fragment).commitAllowingStateLoss();
                    break;
                case R.id.navigation_menu3:
                    transaction.replace(R.id.frame_home, menu3Fragment).commitAllowingStateLoss();
                    break;
                case R.id.navigation_menu4:
                    transaction.replace(R.id.frame_home, menu4Fragment).commitAllowingStateLoss();
                    break;
            }
            return false;
        }
    }

Answer 1

尝试像这样最后返回true

 class ItemSelectedListener implements BottomNavigationView.OnNavigationItemSelectedListener {
    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
        FragmentTransaction transaction = fragmentManager.beginTransaction();

        switch (menuItem.getItemId()) {
            case R.id.navigation_menu1:
                transaction.replace(R.id.frame_home, menu1Fragment).commitAllowingStateLoss();
                break;
            case R.id.navigation_menu2:
                transaction.replace(R.id.frame_home, menu2Fragment).commitAllowingStateLoss();
                break;
            case R.id.navigation_menu3:
                transaction.replace(R.id.frame_home, menu3Fragment).commitAllowingStateLoss();
                break;
            case R.id.navigation_menu4:
                transaction.replace(R.id.frame_home, menu4Fragment).commitAllowingStateLoss();
                break;
        }
        return true;
    }
}

Answer 2

尝试此代码。

 return false;
 or 
 return true;

  public boolean onNavigationItemSelected(@NonNull MenuItem item) {
    // uncheck the other items.
    mMenuId = item.getItemId();
    for (int i = 0; i < mBtmView.getMenu().size(); i++) {
        MenuItem menuItem = mBtmView.getMenu().getItem(i);
        boolean isChecked = menuItem.getItemId() == item.getItemId();
        menuItem.setChecked(isChecked);
    }

    switch (item.getItemId()) {
        case R.id.action_food: {
        }
        break;
        case R.id.action_medical: {
        }
        break;
        case R.id.action_yoga: {
        }
        break;
        case R.id.action_postures: {
        }
        break;
    }
    return true;
}

未选择BottomNavigationView的菜单

2 个答案: