Question

在我的应用程序中，我使用导航抽屉从一个片段移动到另一个片段。

如果我从about_us片段转移到另一个片段，那么如果我再次回到相同的状态，则活动不会恢复，相反应用程序将被关闭。

任何人都可以告诉我代码中的问题，请告诉我修复此问题的解决方案。

public class AboutUsFragment extends Fragment {

public AboutUsFragment(){}

private GoogleMap gmap;

static final double latitude = 33.12615;
static final double longitude = 80.21932;

TextView aboutUs;

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

    View rootView = inflater.inflate(R.layout.fragment_about_us, container, false);

    initilizeMap();

    return rootView;

}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    // TODO Auto-generated method stub
    super.onActivityResult(requestCode, resultCode, data);
}

@Override
public void onActivityCreated(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);

    View aboutUs = getActivity().findViewById(R.id.about_us_content_view);

    try {
        // Loading map
        initilizeMap();

        //To enable compass
        gmap.getUiSettings().setCompassEnabled(true);

        //To locate the school - Creating Marker
        MarkerOptions marker = new MarkerOptions().position(new LatLng(latitude, longitude)).title("School Location");

        // adding marker
        gmap.addMarker(marker);

        //We assigned latitude and longitude in Coordinate
        LatLng coordinate = new LatLng(latitude, longitude);
        CameraUpdate schoolLocation = CameraUpdateFactory.newLatLngZoom(coordinate, 5);
        gmap.animateCamera(schoolLocation);

        CameraPosition cameraPosition = new CameraPosition.Builder()
        .target(coordinate)         // Sets the center of the map to Mountain View
        .zoom(17)                   // Sets the zoom
        .bearing(90)                // Sets the orientation of the camera to east
        .tilt(30)                   // Sets the tilt of the camera to 30 degrees
        .build();                   // Creates a CameraPosition from the builder
        gmap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

    } catch (Exception e) {
        e.printStackTrace();
    }

}

private void initilizeMap()
{
    if (gmap == null) {
        gmap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();

        // check if map is created successfully or not
        if (gmap == null) {
            Toast.makeText(getActivity(), "Sorry! unable to create maps", Toast.LENGTH_SHORT).show();

        }
    }
}

@Override
public void onResume() {
    super.onResume();
    initilizeMap();
}
}

我的about_us.xml是

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:name="com.google.android.gms.maps.MapFragment"
    android:layout_width="match_parent"
    android:layout_height="220dp" />

<ScrollView
    android:id="@+id/scrollView1"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:layout_below="@+id/map"
    android:layout_centerHorizontal="true" >

    <RelativeLayout
        android:id="@+id/RelativeLayout1"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/about_us_heading_View"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:text="@string/about_us"
            android:paddingTop="5dp"
            android:paddingLeft="10dp"
            android:textAppearance="?android:attr/textAppearanceLarge" />

        <TextView 
            android:id="@+id/about_us_content_view"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentTop="true"
            android:text="@string/abouts_us_content"
            android:paddingTop="55dp"
            android:paddingLeft="10dp"
            android:paddingRight="10dp"
            android:textAppearance="?android:attr/textAppearanceMedium"/>

    </RelativeLayout>
</ScrollView>



</RelativeLayout>

因为我对Fragment完全陌生。有人请告诉我一个noob修复它的方法。非常感谢。

Answer 1

Fragment with mapFragment in layout crashes when you resume cause for a fragment onCreateView is called every time you visit it every time.
Try to make your rootView static like below,

public static View mRootView;
    public static boolean mOnRangeChange= false;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        if(mRootView==null){
            mRootView = inflater.inflate(R.layout.fragment_map, container, false);
        }else{
            ViewGroup parent = (ViewGroup) mRootView.getParent();
            if (parent != null)
                parent.removeView(mRootView);
        }
        map_layout = (FrameLayout) mRootView.findViewById(R.id.map_layout);
        mcategory = (Button) mRootView.findViewById(R.id.contact_categories);
        mSharedpreferenceUtility = SharedpreferenceUtility.getInstance(getActivity());
        mcategory.setOnClickListener(this);
        try {
            initializeMap(mRootView);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return mRootView;
    }

Answer 2

在提交fragmnetTransaction

之前将片段添加到backstack

FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.addToBackStack(null);
    ft.replace(R.id.content_frame, fragment).commit();

Fragment中的onResume方法无法正常工作

2 个答案: