显示片段后谷歌地图缓慢

Question

我在Activity FrameLayout中显示各种片段。我显示的第一个片段是谷歌地图。为了显示片段，我将FrameLayout与片段交换。接下来我显示一个片段，然后推到后台。弹出后台堆栈后，谷歌地图变得非常缓慢且滞后。如果我覆盖onBackPressed，从backstack中删除推送的片段，然后重新创建Google Map片段，Google Map会按预期响应。重写onBackPressed似乎是一种解决方法。

为什么地图缓慢且滞后？

这是我的代码（没有我提到的onBackPressed函数）：

MainActivity

public class MainActivity extends AppCompatActivity {

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

        displayFragment(new MapFragment());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        try {
            int id = item.getItemId();

            if(id == R.id.displayBlankFragment) {
                displayDialogFragment(new BlankFragment());
                return true;
            }
        } catch(Exception e) {
            Toast.makeText(this, e.getMessage(), Toast.LENGTH_LONG).show();
        }

        return super.onOptionsItemSelected(item);
    }

    private void displayFragment(Fragment fragment) {

        FragmentTransaction t = getSupportFragmentManager().beginTransaction();
        t.replace(R.id.frame, fragment);
        t.commit();
    }

    private void displayDialogFragment(Fragment fragment) {

        FragmentTransaction t = getSupportFragmentManager().beginTransaction();
        t.replace(R.id.frame, fragment);
        t.addToBackStack(null);
        t.commit();
    }
}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin">

    <FrameLayout
        android:id="@+id/frame"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
    </FrameLayout>
</RelativeLayout>

MapFragment

public class MapFragment extends Fragment {

    private View view;

    public MapFragment() {
    }

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

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        if(view == null) {
            view = inflater.inflate(R.layout.fragment_map, container, false);
        }

        return view;
    }
}

fragment_map.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
             android:layout_width="match_parent"
             android:layout_height="match_parent">

    <fragment
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        class="com.google.android.gms.maps.SupportMapFragment" >
    </fragment>

</FrameLayout>

BlankFragment

public class BlankFragment extends Fragment {

    public BlankFragment() {
    }

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

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment_blank, container, false);
    }
}

fragment_blank.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
             android:layout_width="match_parent"
             android:layout_height="match_parent">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="@string/hello_blank_fragment"/>

</FrameLayout>