Android Fragment SetTitle（）不起作用

Question

每当一个片段被调用它没有设置时，

setTitle（menuItem.getTitle（））就无法工作。当我尝试从一个片段改变或跳转到那个时，动作栏只设置了应用名称。< / p>

    public class MainActivity extends AppCompatActivity {

    Toolbar mToolBar;
    NavigationView mNavigationView;
    DrawerLayout mDrawerLayout;
    ActionBarDrawerToggle mActionBarDrawerToggle;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if(savedInstanceState == null){
            getSupportFragmentManager().beginTransaction().replace(R.id.containerView,new HomeFragment()).commit();
        }

        mToolBar = (Toolbar)findViewById(R.id.toolbar);
        setSupportActionBar(mToolBar);

        mDrawerLayout = (DrawerLayout)findViewById(R.id.drawerLayout);
        mNavigationView = (NavigationView)findViewById(R.id.navigationDrawer);


        mActionBarDrawerToggle = setupDrawerToggle();

        mDrawerLayout.addDrawerListener(mActionBarDrawerToggle);

        setupDrawerContent(mNavigationView);
    }

    private ActionBarDrawerToggle setupDrawerToggle(){

        return new ActionBarDrawerToggle(this,mDrawerLayout,mToolBar,R.string.drawer_open,R.string.drawer_close);
    }

    private void setupDrawerContent(NavigationView mNavigationView){
        mNavigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(MenuItem menuItem) {
                selectDrawerItem(menuItem);
                return true;
            }
        });
    }

    public void selectDrawerItem(MenuItem menuItem){


        Fragment fragment = null;

        Class fragmentClass;


        switch (menuItem.getItemId()){


            case R.id.nav_home:
                fragmentClass = HomeFragment.class;
                break;

            case R.id.nav_rate_card:
                fragmentClass = RateCardFragment.class;
                break;

            case R.id.nav_orders:
                fragmentClass = OrderFragment.class;
                break;

            case R.id.nav_setting:
                fragmentClass = SettingFragment.class;
                break;

            case R.id.nav_about_us:
                fragmentClass = AboutUsFragment.class;
                break;

            default:
                fragmentClass = HomeFragment.class;

        }

        try{
            fragment = (Fragment) fragmentClass.newInstance();
        }catch (Exception ex){
            ex.printStackTrace();
        }


        FragmentManager fragmentManager = getSupportFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.containerView,fragment).commit();


        // Highlight the selected item has been done by NavigationView
        //menuItem.setChecked(true);
        // Set action bar title
        setTitle(menuItem.getTitle());

        mDrawerLayout.closeDrawers();
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // The action bar home/up action should open or close the drawer.
        switch (item.getItemId()) {
            case android.R.id.home:
                mDrawerLayout.openDrawer(GravityCompat.START);
                return true;
        }

        if (mActionBarDrawerToggle.onOptionsItemSelected(item)){
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);

        mActionBarDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        // Pass any configuration change to the drawer toggles
       mActionBarDrawerToggle.onConfigurationChanged(newConfig);
    }

}

Answer 1

使用getSupportActionBar().setTitle()并尝试。

Answer 2

在toolbar.xml中取一个textview并访问它。就像这个

        if(waist <= 0 || height <= 0)
        if (waist <= 0) {
            MessageBox.Show("Please enter a number that greater than 60");
        }
        if (height <=0 ) {
            MessageBox.Show("Please enther a number that greater than 120");
                }