导航抽屉:如何在启动时设置所选项目？

Question

我的代码完美无缺:每次点击导航抽屉中的项目时,都会选择该项目.

当然我想用默认片段(home)启动应用程序,但导航抽屉没有选择项目.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;
[...]

我想我需要在这里编辑:

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

或者在onCreateApp启动时使用FragmentTransaction.

感谢您的支持.

Answer 1

使用以下代码:

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

打电话后调用此方法 setNavDrawer();

该getItem(int index)方法获取MenuItem然后你可以调用setChecked(true);on MenuItem,你剩下要做的就是找出默认具有哪个元素索引,并用该索引替换0.

您可以通过调用选择(突出显示)该项目

onNavigationItemSelected(navigationView.getMenu().getItem(0));

以下是参考链接:http://thegeekyland.blogspot.com/2015/11/navigation-drawer-how-set-selected-item.html

编辑 无法在nexus 4上运行,支持库版本24.0.0.我推荐使用

navigationView.setCheckedItem(R.id.nav_item);

由@kingston在下面回答.

Answer 2

你也可以打电话:

navigationView.setCheckedItem(id);

此方法在API 23.0.0中引入

例

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      tools:ignore="UnusedIds">

    <group
        android:id="@+id/group"
        android:checkableBehavior="single">
        <item
            android:id="@+id/menu_nav_home"
            android:icon="@drawable/ic_home_black_24dp"
            android:title="@string/menu_nav_home" />
    </group>
</menu>

注意: android:checkableBehavior="single"

另请参见本

Answer 3

对我来说这两种方法都不起作用:

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

尝试这个,它适合我.

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

Answer 4

示例(NavigationView.OnNavigationItemSelectedListener):

private void setFirstItemNavigationView() {
        navigationView.setCheckedItem(R.id.custom_id);
        navigationView.getMenu().performIdentifierAction(R.id.custom_id, 0);
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setFirstItemNavigationView();
}

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    FragmentManager fragmentManager = getFragmentManager();

    switch (item.getItemId()) {
        case R.id.custom_id:
            Fragment frag = new CustomFragment();

            // update the main content by replacing fragments
            fragmentManager.beginTransaction()
                    .replace(R.id.viewholder_container, frag)
                    .setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
                    .addToBackStack(null)
                    .commit();
            break;
    }

TKS

Answer 5

Googles总是存在问题"哦,太棒了"支持库.如果要在不降级支持库版本的情况下检查项目,只需在设置选中状态之前设置checkable.

MenuItem item = drawer.getMenu().findItem(R.id.action_something);
item.setCheckable(true);
item.setChecked(true);

如果在菜单xml文件中设置了checkable,它也可能有效

Answer 6

您可以使用以下1-liner突出显示并选择项目:

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

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

Answer 7

API 23提供以下方法:

navigationView.setCheckedItem(R.id.nav_item_id);

但是,由于某种原因,此功能不会导致导航项后面的代码运行.该方法当然突出显示导航抽屉中的项目,或"检查"它,但OnNavigationItemSelectedListener如果您的启动屏幕取决于导航抽屉选择,它似乎不会在启动时调用结果为空白屏幕.可以手动调用监听器,但看起来很hacky:

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

上面的代码假定:

1. 您已NavigationView.OnNavigationItemSelectedListener在活动中实施
2. 你已经打过:
   navigationView.setNavigationItemSelectedListener(this);
3. 您要选择的项目位于0位置

Answer 8

你必须为此调用2个函数:

第一:用于排除您在onNavigationItemSelected侦听器中实现的命令:

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);

我打了两个函数,它对我有用.

Answer 9

以下代码仅选择菜单项:

navigationView.setCheckedItem(id);

要选择并打开菜单项,请在上面的行后面添加以下代码.

onNavigationItemSelected(navigationView.getMenu().getItem(0));

Answer 10

最简单的方法是从 xml 中选择它，如下所示，

<menu>
   <group android:checkableBehavior="single">
         <item
              android:checked="true"
              android:id="@+id/nav_home"
              android:icon="@drawable/nav_home"
              android:title="@string/main_screen_title_home" />

注意行 android:checked="true"