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

出于某种原因,最好使用ID来查找MenuItem。

drawer.getMenu().findItem(R.id.action_something).setChecked(true);

其他回答

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。

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。

API 23提供了以下方法:

navigationView.setCheckedItem(R.id.nav_item_id);

但是,由于某种原因,这个函数没有导致导航项后面的代码运行。该方法当然会突出显示导航抽屉中的项目,或“检查”它,但它似乎不会调用OnNavigationItemSelectedListener,导致启动时出现空白屏幕,如果您的启动屏幕依赖于导航抽屉的选择。可以手动调用监听器,但看起来很俗气:

if (savedInstanceState == null) this.onNavigationItemSelected(navigationView.getMenu().getItem(0));

上面的代码假设:

你已经实现了 NavigationView。OnNavigationItemSelectedListener在你的活动 您已经呼叫过: navigationView.setNavigationItemSelectedListener(这个); 您要选择的项目位于位置0

出于某种原因,最好使用ID来查找MenuItem。

drawer.getMenu().findItem(R.id.action_something).setChecked(true);

对我来说,这两种方法都不奏效:

navigationView.getMenu .setChecked .getItem (0) () (true); navigationView.setCheckedItem (id);

试试这个,对我很管用。

onNavigationItemSelected (navigationView.getMenu () .findItem (R.id.nav_profile));