如何在抽屉菜单中更改第一个片段 [英] How I can change my first fragment in drawerMenu

问题描述

我遇到了麻烦，必须通过程序设置第一个显示的片段(每次尝试打开抽屉时都必须更改第一个片段)，我搜索了很多但无法更改代码.帮帮我.

I'm In trouble and I have to set my first shown fragment by a program ( I have to change the first fragment every time I try to open the drawer), I searched a Lot but I can't change my code. Help me guys.

我的抽屉代码:

public class Maincontant extends AppCompatActivity {

    private AppBarConfiguration mAppBarConfiguration;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maincontant);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        NavigationView navigationView = findViewById(R.id.nav_view);


        mAppBarConfiguration = new AppBarConfiguration.Builder(
                R.id.nav_gallery,R.id.nav_home , R.id.nav_slideshow,
                R.id.nav_tools, R.id.nav_share, R.id.nav_contact)
                .setDrawerLayout(drawer)
                .build();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);//
        NavigationUI.setupActionBarWithNavController(this, navController,mAppBarConfiguration);//
        NavigationUI.setupWithNavController(navigationView, navController);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.maincontant, menu);

        return true;
    }


    @Override
    public boolean onSupportNavigateUp() {
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        return NavigationUI.navigateUp(navController, mAppBarConfiguration)
                || super.onSupportNavigateUp();
    }
}

推荐答案

您可以使用 setNavigationItemSelectedListener ，然后可以像下面这样调用特定的 fragment :

You can use setNavigationItemSelectedListener then can call specific fragment like this following:

navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem menuItem) {
                Log.e("selected","selected---menu---"+menuItem.toString());

                if (drawer.isDrawerVisible(GravityCompat.START)) {
                    drawer.closeDrawer(GravityCompat.START);
                } else {
                    drawer.openDrawer(GravityCompat.START);
                }
                if(menuItem.toString().equalsIgnoreCase("Gallery"))
                {
                    navController.navigate(R.id.nav_gallery2);
                }
                else if(menuItem.toString().equalsIgnoreCase("Home"))
                {
                    navController.navigate(R.id.nav_home);
                }
                else
                {
                    navController.navigate(R.id.nav_slideshow);
                }
                return true;
            }
        });

如果您使用的是 NavigationGraph ，则必须在其中指定 fragment . navController.navigate(R.id.nav_gallery2); ，我已在 NavigationGraph 上指定了此 fragment ，但未在 DrawerMenu 上指定代码>.

If you are using NavigationGraph then you will have to specify the fragment there. navController.navigate(R.id.nav_gallery2);, I have specified this fragment on NavigationGraph, But not on DrawerMenu.

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