Moving MapFragment (SurfaceView) causes black back

问题:

I'm trying to implement new Android Google Maps API (v2). However it doesn't seem to go well with SlidingMenu. As you may know, MapFragment implementation is based on SurfaceView. The problem is that the SurfaceView doesn't like moving it around - I mean placing it in movable views:

• ViewPager,
• ScrollView,
• ListView,
• or the aforementioned SlidingMenu.

When you move it, it leaves a black hole in the place where its pixels originally layed. It looks something like this.

This problem can be partially solved by specifying a transparent background on the SurfaceView or even placing a transparent View over it. I just can't figure if only for me the results are unacceptable, or if I have a different problem which makes it look how it looks.

To see how it looks, please watch THIS VIDEO.

(sorry for the quality, but the problem can be seen easily anyway)

When a normal listview (the orange screen) is pulled away while opening SlidingMenu, the animation is smooth and nice. But as soon as the MapFragment appears, there's some weird refreshing/flickering/synchronization issue on the map.

Tested on HTC One S and Samsung Galaxy ACE.

---

My super-duper-crazy idea of solving it: each time the opening animation starts, take a screenshot of the MapFragment (it should be possible with SurfaceView) and lay it over for the duration of the animation. But I really don't know how to do it... Taking screenshot of a map isn't possible, but maybe someone will get inspired by this.

Or maybe disable redrawing the map some other way, I don't know.

---

UPDATE:

Found this.

It appears that SurfaceView can be changed to TextureView to remove those limitations. But since MapFragment is based on SurfaceView, I don't know if it can be achieved.

Another update It appears that this issue has been resolved on devices 4.1+. They just used TextureView. but on lower versions we still have to use workarounds.

回答1:

Of course the proper solution will be for Google to fix the problem (see Android Maps V2 issue 4639: http://code.google.com/p/gmaps-api-issues/issues/detail?id=4639).

However, one of my coworkers suggested simply extending the map beyond its container. If we extend the map fragment beyond the visible region of its container, like so:

android:layout_marginLeft="-40dp"
android:layout_marginRight="-40dp"

we can reduce/eliminate the flickering. Newer devices (e.g. Galaxy Nexus) show no flickering after this hack, and older devices (e.g. LG Optimus V) show reduced flickering. We have to extend margins on both sides so that info windows are centered when they're selected.

---

Update: This issue was fixed by Google on Aug. 28, but I'm guessing it still has to be rolled into a release.

回答2:

You can use this library

https://github.com/NyxDigital/NiceSupportMapFragment/

this works fine for me.

回答3:

Here's a crazy idea, don't move the MapView ;-)

That is, create a MapView full screen width behind your app in a FrameLayout. Then lay your views on top, and punch a hole through to the MapView in the position you need to display it. When moving you'll need to update the map position to stay in sync so the user keeps seeing the same section of the map, but that should update better than moving a surface view around.

回答4:

Well, Quoting Dianne Hackborn (an Android framework engineer)

The surface view is actually BEHIND your window, and a hole punched in the window for you to see it. You thus can put things on top of it in your window, but nothing in your window can appear behind it. Original post

This architecture is part of why you see these flickers.

Some flickering sometimes appear due to double buffers: Android coding blog explains further.

You can also try and subclass the SurfaceView to try and draw the background differently. I haven't seen an example of this that doesn't change the z-index to be that of the top. Check out this SO post

Otherwise, I recommend only getting the SurfaceHolder after your view is focused (try and make a temporary view until then) and removing the SurfaceView whilst not in focus and on screen.

回答5:

Taking screenshot of a map isn't possible, but maybe someone will get inspired by this.

It's possible with the snapshot interface from GoogleMap. Now you can display a snapshot of the map while scrolling the page. With this I solved my problem with the ViewPager, maybe you can change the code to fit your SlidingMenu.

Here is my code to setting the snapshot (it's in the same fragment as map, called FragmentMap.java):

public void setSnapshot(int visibility) {
    switch(visibility) {
    case View.GONE:
        if(mapFragment.getView().getVisibility() == View.VISIBLE) {
            getMap().snapshot(new SnapshotReadyCallback() {
                @Override
                public void onSnapshotReady(Bitmap arg0) {
                    iv.setImageBitmap(arg0);
                }
            });
            iv.setVisibility(View.VISIBLE);
            mapFragment.getView().setVisibility(View.GONE);
        }
        break;
    case View.VISIBLE:
        if(mapFragment.getView().getVisibility() == View.GONE) {
            mapFragment.getView().setVisibility(View.VISIBLE);
            iv.setVisibility(View.GONE);
        }
        break;
    }
}

Where "mapFragment" is my SupportedMapFragment and "iv" is an ImageView (make it match_parent).

And here I am controlling the scroll:

pager.setOnPageChangeListener(new OnPageChangeListener() {
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            if(position == 0 && positionOffsetPixels > 0 || position == 1 && positionOffsetPixels > 0) {
                ((FragmentMap)adapter.getRegisteredFragment(1)).setSnapshot(View.GONE);
            } else if(position == 1 && positionOffsetPixels == 0) {
                ((FragmentMap)adapter.getRegisteredFragment(1)).setSnapshot(View.VISIBLE);
            }
        }
        @Override
        public void onPageScrollStateChanged(int arg0) {}
        @Override
        public void onPageSelected(int arg0) {}
    });

My fragment with map (FragmentMap) is on position 1, so I need to controll the scroll from position 0 to 1 and from position 1 to 2 (the first if-clause). "getRegisteredFragment()" is a function in my custom FragmentPagerAdapter, in which I have a SparseArray(Fragment) called "registeredFragments".

So, whenever you scroll to or from your map, you always see a snapshot of it. This works very well for me.

回答6:

To prevent the MapView(it is actually a SurfaceView) creating the black holes, I add a empty view with transparent background color to cover the whole MapView, such that it can prevent MapView from generating a black "hole". It may work for your situation.

回答7:

I got same problem with a webview and SlidingMenu and I solved by modifying SlidingMenu source code as explained here by main developer.

Comment out the hardware acceleration in the manageLayers method of SlidingMenu. This seems to be the only solution since SurfaceViews don't work.

回答8:

Another alternative solution is to use the new GoogleMap.snapshot() function, and using a screenshot of the map instead; as described here.

回答9:

In my scenario, I had an initial Fragment, which on a button click swapped in a second fragment with a MapFragment inside it. I noticed that this flicker only occurred the first time you would swap the fragment - popping the back stack, and swapping in another fragment of the same type did not cause a flicker.

So figuring it had something to do with adding an initial SurfaceView to the window, I tried adding an empty instance of a SurfaceView to my initially loaded fragment, behind it's main view. And bingo, no more flicker when animating in the next fragment!

I know it's not the cleanest solution, but it works. The Google MapFragment (or SupportMapFragment in my case) still works fine, as the unused SurfaceView is in the previous fragment.

I should add I am using the v2 API.

Update @VenomVendor

I add the empty SurfaceView to the first fragment to be shown, at index 0 - behind the main view. In my case, the Home fragment is the previous fragment to one that contains the Google Maps fragment, not sure if that matters:

import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class HomeFragment extends FragmentBase {
private SurfaceView sview;

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_home, container, false);

    //this fixes google maps surface view black screen animation issue
    sview = new SurfaceView(getActivity());
    sview.setZOrderOnTop(true);    // necessary
    SurfaceHolder holder = sview.getHolder();
    holder.setFormat(PixelFormat.TRANSPARENT);

    container.addView(sview, 0);
    ...
}

回答10:

add android:hardwareAccelerated="true" in your manifest file.

eg: <application android:name=".Sample" android:hardwareAccelerated="true" />

回答11:

I had same issue of black screen on scrolling of list view, i was using map fragment with list view in same screen i have resolved this issue with use of the magical property in xml where i am talking list view just we have to put android:scrollingCache="false".my issue is fixed try this property to stop lagging and flickering in your maps.

回答12:

Guys the best solution I found was to instantiate your support map through this. Does wonders

SupportMapFragment mapFragment = SupportMapFragment.newInstance(new GoogleMapOptions().zOrderOnTop(true));

回答13:

try adding..

getHolder().setFormat(PixelFormat.TRANSLUCENT);

to your SurfaceView's constructor. The TextureView should also work, but will require you to drop support for sub api 14 devices.

回答14:

Change Your FrameLayout to RelativeLayout if Possible

回答15:

I had the same problem and used a workaround based on changing the "Visibility".

private GoogleMap mMap;
private SupportMapFragment mMapFragment;

mMapFragment = ((SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.mapFragment));
mMap = mMapFragment.getMap();

//Change the visibility to 'INVISIBLE' before the animation to go to another fragment.
mMapFragment.getView().setVisibility(View.INVISIBLE);

//Change the visibility to 'VISIBLE' after coming back to the original fragment that has map fragment.
mMapFragment.getView().setVisibility(View.VISIBLE);

回答16:

This worked for me... Add map:zOrderOnTop="true" to your fragment as this...

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

Remember to add this to your parent ScrollView

xmlns:map="http://schemas.android.com/apk/res-auto"

回答17:

Here's a very simple workaround I used to get rid of the flashing in a ViewPager. I would imagine the same will hold true for any Fragment or other dynamically added MapView.

The problem doesn't really seem to be the MapView itself, but the resources needed to run the MapView. These resources are only loaded the first time you fire up a MapView in your activity and re-used for each subsequent MapView, as you would expect. This loading of resources is what causes the screen to flash.

So to remove the flashing, I just included another MapView in the layout of my Activity (location in the activity is irrelevant). As soon as the Activity has loaded, I just set the Visibility of the extra MapView to GONE. This means all the resources needed for your MapView are ready for when you fire up any of your Fragments using MapViews with no lag, no flashing, all happiness.

This is of course a workaround and not a real 'solution' to the underlying problem but it will resolve the side effects.

So to cover off the code used for completeness:

Randomly (but cleanly) placed in my Activity Layout:

<com.google.android.gms.maps.MapView
        android:id="@+id/flash_map"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

Then in my Activity Class

private MapView flashMap;

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

            // Code omitted

    try {
        MapsInitializer.initialize(this);
    } catch (GooglePlayServicesNotAvailableException e) {
        e.printStackTrace();
    }
    flashMap = (MapView)findViewById(R.id.flash_map);
    flashMap.onCreate(savedInstanceState);
}

@Override
public void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
        flashMap.onSaveInstanceState(outState);
}

@Override
public void onResume() {
    super.onResume();
    flashMap.onResume();
    flashMap.setVisibility(View.GONE); // Just like it was never there...
}

@Override
public void onPause() {
    flashMap.onPause();
    super.onPause();
}

@Override
public void onDestroy() {
    flashMap.onDestroy();
    super.onDestroy();
}

@Override
public void onLowMemory() {
    super.onLowMemory();
    flashMap.onLowMemory();
}