非常容易学的android笔记4

Tue, Dec 20, 2022 One-minute read

nav drawer菜单

TextView

DrawerNav

TextView

DrawerNav

TextView

DrawerNav

新建一个menu

TextView

nav_menu

tools:showIn=“navigation_view”

这个就是形成右边那条缝的

主菜单activity_main.xml

TextView

LinearLayout

这个 NavigationView 里面包了两个

app:headerLayout="@layout/main_navigate"

app:menu="@menu/nav_menu"

TextView

Navigation

TextView

Navigation headerLayout

需要几个fragment，就是导航过去的界面，上个教程有。

再说下3个点的这些图标问题，其实不需要放，只需要设置menu就可以，但是有时候menu是假的，才需要放图标

TextView

more icon

这里就是一旦设置好menu，这里几个点就自己出现了。

MainActivity.class

注入 drawerLayer ， navigationView， toolbar;

public class MainActivity extends AppCompatActivity  {

    DrawerLayout drawerLayer;
    NavigationView navigationView;
    Toolbar toolbar;

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

        drawerLayer = findViewById(R.id.drawer_layout);
        navigationView = findViewById(R.id.nav_view);
        toolbar = findViewById(R.id.toolbar);

划掉这个，不然会出错

This Activity already has an action bar supplied by the window decor. Do not request Window.>FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.

很多人会在主菜单中把action bar给设为 false，如果自定义的话，我这边比较简单，所以就自带了，这一行就不能出现了

// setSupportActionBar(toolbar);


        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(this, drawerLayer, toolbar, R.string.open_nav, R.string.close_nav);
        drawerLayer.addDrawerListener(toggle);

        toggle.syncState();

接下来是导航

 navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {

                switch (item.getItemId()) {
                    case R.id.nav_home:
                        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new fragment_home()).commit();
                        break;
                    case R.id.nav_gallery:
                        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new fragment_gallery()).commit();
                        break;
                    case R.id.nav_slideshow:
                        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new fragment_slideshow()).commit();
                        break;
                }
                drawerLayer.closeDrawer(GravityCompat.START);
                return true;
                }
            });

        if (savedInstanceState != null) {
        getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, new fragment_home()).commit();
        navigationView.setCheckedItem(R.id.nav_home);
    }
  • 用户点击 Back 键时系统调用的方法
 public void onBackPressed() {
        if (drawerLayer.isDrawerOpen(GravityCompat.START)) {
            drawerLayer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

好了