Question

我使用Android工作室创建activity，但是我不知道如何在启动活动时设置fragment class。每当我开始activity时，我都会看到一个空白屏幕。这意味着主屏幕不是fragment class屏幕。

代码如下：

public class Dashboard extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    ActionBarDrawerToggle toggle;
    DrawerLayout drawer;
    NavigationView navigationView;
    FloatingActionButton fab;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_dashboard);


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

        fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

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

        navigationView = (NavigationView) findViewById(R.id.nav_view);
        //navigationView.setNavigationItemSelectedListener(this);



    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.dashboard, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.


        selectDrawerItem(item);

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



    private void selectDrawerItem(MenuItem menuItem) {

        Fragment fragment = null;
        Class fragmentClass;
        switch(menuItem.getItemId()) {
            case R.id.nav_dashboard:
                fragmentClass = DashboardFragment.class;
                break;
            case R.id.nav_importexport:
                fragmentClass = ImportexportFragment.class;
                break;
            case R.id.nav_backuprestore:
                fragmentClass = BackuprestoreFragment.class;
                break;
            case R.id.nav_setting:
                fragmentClass = SettingFragment.class;
                break;
            default:
                fragmentClass = DashboardFragment.class;
        }

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

        // Insert the fragment by replacing any existing fragment
        android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.content_dashboard, fragment).commit();

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

    }

}

Answer 1

您已经在点击抽屉项目时设置了片段类。

 case R.id.nav_dashboard:
                fragmentClass = DashboardFragment.class;
                break;

以下是您获取ID并打开DashboardFragment的多个片段的代码。

 android.support.v4.app.FragmentManager fragmentManager = getSupportFragmentManager();
        fragmentManager.beginTransaction().replace(R.id.content_dashboard, fragment).commit();

片段在这里被很好地替换了。

如何在Android中为新的导航抽屉设置基本活动？

1 个答案: