我的代码工作得很完美:每次单击导航抽屉中的项目时,项目就会被选中。

当然,我想启动应用程序与默认片段(家),但导航抽屉没有选择的项目。如何以编程方式选择该项目?

public class BaseApp extends AppCompatActivity {

    //Defining Variables
    protected String LOGTAG = "LOGDEBUG";
    protected Toolbar toolbar;
    protected NavigationView navigationView;
    protected DrawerLayout drawerLayout;

    private DateManager db = null;

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

        navigationView = (NavigationView) findViewById(R.id.navigation_view);


        // set the home/dashboard at startup

        FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
        fragmentTransaction.replace(R.id.frame, new DashboardFragment());
        fragmentTransaction.commit();

        setNavDrawer();
    }

    private void setNavDrawer(){

        // Initializing Toolbar and setting it as the actionbar
        toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        //Initializing NavigationView

        //Setting Navigation View Item Selected Listener to handle the item click of the navigation menu
        navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {

            // This method will trigger on item Click of navigation menu
            @Override
            public boolean onNavigationItemSelected(MenuItem menuItem) {


                //Checking if the item is in checked state or not, if not make it in checked state

                // I THINK THAT I NEED EDIT HERE...

                if (menuItem.isChecked()) menuItem.setChecked(false);
                else menuItem.setChecked(true);

                //Closing drawer on item click
                drawerLayout.closeDrawers();


                //Check to see which item was being clicked and perform appropriate action
                switch (menuItem.getItemId()) {    

                    //Replacing the main content with ContentFragment 

                    case R.id.home:

                        DashboardFragment dashboardFragment = new DashboardFragment();
                        FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
                        fragmentTransaction.replace(R.id.frame, dashboardFragment,"DASHBOARD_FRAGMENT");
                        fragmentTransaction.commit();
                        return true;
[...]

我认为我需要在这里进行编辑:

if (menuItem.isChecked()) menuItem.setChecked(false);
                    else menuItem.setChecked(true);

或者在onCreate中在App启动时使用FragmentTransaction。

谢谢你的支持。


当前回答

您可以用下面的一行代码突出显示和选择项目:

navigationView.getMenu().performIdentifierAction(R.id.posts, 0);

来源:https://stackoverflow.com/a/31044917/383761

其他回答

您可以用下面的一行代码突出显示和选择项目:

navigationView.getMenu().performIdentifierAction(R.id.posts, 0);

来源:https://stackoverflow.com/a/31044917/383761

首先,为选定的项目创建颜色。这里https://stackoverflow.com/a/30594875/1462969很好的例子。它可以帮助你改变图标的颜色。为了改变所有选定项目的背景添加到您的价值\style.xml文件this

  <item name="selectableItemBackground">@drawable/selectable_item_background</item>

在drawable/selectable_item_background.xml中应该声明selectable_item_background

  <?xml version="1.0" encoding="utf-8"?>
    <selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@color/accent_translucent"
      android:state_pressed="true" />
    <item android:drawable="@android:color/transparent" />
   </selector>

哪里可以在style.xml中声明颜色

 <color name="accent_translucent">#80FFEB3B</color>

在这之后

   // The main navigation menu with user-specific actions
        mainNavigationMenu_ = (NavigationView) findViewById(R.id.main_drawer);
        mainNavigationMenu_.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(MenuItem menuItem) {
                mainNavigationMenu_.getMenu().findItem(itemId).setChecked(true);
                return true;
            }
        });

正如你看到的,我用了这个 .setChecked mainNavigationMenu_.getMenu () .findItem (itemId)(真正的); 设置所选项目。 这里navigationView

 <android.support.design.widget.NavigationView
        android:id="@+id/main_drawer"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/header_main_navigation_menu"
        app:itemIconTint="@color/state_list"
        app:itemTextColor="@color/primary"
        app:menu="@menu/main_menu_drawer"/>

关于你的活动(在抽屉后面):

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawer, toolbar,
               R.string.navigation_drawer_open,
               R.string.navigation_drawer_close);
    drawer.addDrawerListener(toggle);
    toggle.syncState();

    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
    navigationView.setCheckedItem(R.id.nav_portfolio);
    onNavigationItemSelected(navigationView.getMenu().getItem(0));
}

and

@Override
public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    Fragment fragment = null;

    if (id == R.id.nav_test1) {
        fragment = new Test1Fragment();
        displaySelectedFragment(fragment);
    } else if (id == R.id.nav_test2) {
        fragment = new Test2Fragment();
        displaySelectedFragment(fragment);
    }

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}

在菜单中:

<group android:checkableBehavior="single">

    <item
        android:id="@+id/nav_test1"
        android:title="@string/test1" />

    <item
        android:id="@+id/nav_test2"
        android:title="@string/test2" />

  </group>

第一个菜单被高亮显示为默认菜单。

    package com.example.projectdesign;
    import androidx.annotation.NonNull;
    import androidx.appcompat.app.ActionBarDrawerToggle;
    import androidx.appcompat.app.AppCompatActivity;
    import androidx.core.view.GravityCompat;
    import androidx.drawerlayout.widget.DrawerLayout;
    import androidx.fragment.app.Fragment;
         import android.annotation.SuppressLint;
      import android.app.Activity;
     import android.content.Intent;
     import android.os.Bundle;
     import android.view.MenuItem;
    import android.widget.Toast;

    import com.google.android.material.navigation.NavigationView;

    public class MenuDrawer extends AppCompatActivity implements 
    NavigationView.OnNavigationItemSelectedListener{
    public DrawerLayout drawerLayout;
    public ActionBarDrawerToggle actionBarDrawerToggle;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_menu_drawer);

        drawerLayout = findViewById(R.id.my_drwaer_layout);
        actionBarDrawerToggle = new ActionBarDrawerToggle(this, drawerLayout, 
      R.string.nav_open, R.string.nav_close);
        drawerLayout.addDrawerListener(actionBarDrawerToggle);
        actionBarDrawerToggle.syncState();
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        NavigationView navigationView = findViewById(R.id. nav_view ) ;
        navigationView.setNavigationItemSelectedListener( this ) ;
    }
    @SuppressLint("ResourceType")
    @SuppressWarnings ( "StatementWithEmptyBody" )
     @Override
    public boolean onNavigationItemSelected (MenuItem item){
        int id=item.getItemId();
        switch (id){
            case R.id.nav_account:
                Intent intent= new Intent(MenuDrawer.this, UsingBackKey.class);
                startActivity(intent);
                break;
            case R.id.women:
     
     
    getSupportFragmentManager().beginTransaction().replace(R.id.my_drwaer_layout,new 
    Fragment2()).commit();
                break;
            case R.id.men:
                Toast.makeText(getApplicationContext(),"Soon", 
   Toast.LENGTH_SHORT).show();
                break;
            case R.id.kids:
              Toast.makeText(getApplicationContext(),"Welcome to Kids", 
      Toast.LENGTH_SHORT).show();
                break;
        }
        drawerLayout.closeDrawer(GravityCompat.START);
        return super.onContextItemSelected(item);
    }

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


        if (actionBarDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }

        return super.onOptionsItemSelected(item);

    }

    @Override
    public void onBackPressed() {
        if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
            drawerLayout.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
        super.onBackPressed();
    }
}

你必须为此调用2个函数:

首先:执行你在onNavigationItemSelected监听器中实现的命令:

onNavigationItemSelected(navigationView.getMenu().getItem(R.id.nav_camera));

第二:将导航抽屉菜单项的状态更改为选中(或选中):

navigationView.setCheckedItem(R.id.nav_camera);

我调用了两个函数,它对我有效。