在導航抽屜的片段中映射

Question

我的代碼有什么問題？ 我正在嘗試在片段中顯示地圖（按導航抽屜的按鈕）。但是應用程序崩潰，而不是加載它。 Android studio不會顯示錯誤..並且該應用程序可以運行，但是當我單擊導航抽屜菜單上的“圖庫”按鈕時，它應該顯示地圖，但是該應用程序崩潰了。 這是主要活動的代碼...

public class MainActivity extends AppCompatActivity
implements NavigationView.OnNavigationItemSelectedListener, OnMapReadyCallback {


    SupportMapFragment sMapFragment;


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

        sMapFragment = SupportMapFragment.newInstance();

        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton 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();
            }
        });

        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.setDrawerListener(toggle);
        toggle.syncState();

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

        android.app.FragmentManager fm = getFragmentManager();
        fm.beginTransaction().replace(R.id.content_frame, new MainFragment()).commit();

        sMapFragment.getMapAsync(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.main, 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) {

        android.app.FragmentManager fn = getFragmentManager();
        android.support.v4.app.FragmentManager sFm = getSupportFragmentManager();
        int id = item.getItemId();

        if (sMapFragment.isAdded())
            sFm.beginTransaction().hide(sMapFragment).commit();

        if (id == R.id.nav_camera) {
            fn.beginTransaction().replace(R.id.content_frame, new ImportFragment()).commit();

        } else if (id == R.id.nav_gallery) {
            if (!sMapFragment.isAdded())
                sFm.beginTransaction().add(R.id.map, sMapFragment).commit();
            else
                sFm.beginTransaction().show(sMapFragment).commit();

        } else if (id == R.id.nav_slideshow) {

        } else if (id == R.id.nav_manage) {

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_send) {

        }

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

    @Override
    public void onMapReady(GoogleMap googleMap) {

    }
}

Answer 1

在您的onCreate方法中調用mapFragment.getMapAsync(this); 有關更詳細的說明，請參見此處 。