带有 Google Maps API v2的 ViewPager: 神秘的黑色视图

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You haven't given much detail so there is only so much I can suggest. I had a similar issue that the screen flickered between views in the pager. It turned out to be the mapView inflating when swapping between pages the first time.

To be clear I had 3 pages in my pager and my map was the last page.

To solve this I found that setting the number of off screen pages to 2 (this worked in the case above) that when my fragment started it loaded all the views at once.

See http://developer.android.com/reference/android/support/v4/view/ViewPager.html#setOffscreenPageLimit (int)

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最佳答案

I was able to stop the black surface being left behind after transition by placing another view with a transparent background on top of the ViewPager inside a FrameLayout:

<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent" >


<android.support.v4.view.ViewPager
android:id="@+id/fragment_container"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</android.support.v4.view.ViewPager>


<!-- hack to fix ugly black artefact with maps v2 -->
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/transparent" />


</FrameLayout>

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Had the same problem with SlidingMenu and ViewPager. I noticed that control buttons in map fragment are not black in the left behind artifact. I solved the problem by overriding the onCreateView() method of MapFragment (SupportMapFragment)

@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup view,
Bundle savedInstance) {


View layout = super.onCreateView(inflater, view, savedInstance);
FrameLayout frameLayout = new FrameLayout(getActivity());
frameLayout.setBackgroundColor(
getResources().getColor(android.R.color.transparent));
((ViewGroup) layout).addView(frameLayout,
new ViewGroup.LayoutParams(
LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT
)
);
return layout;
}

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There is one more solution to this problem. I am showing MapFragment within another fragment. The MapFragment is dynamically added into the a FrameLayout.

The solution is to use frameLayout.setVisibility(View.Visible) and frameLayout.setVisibility(View.Gone) on open and close events of sliding menu. It dosent require an extra view to be added. And the black area is completely gone.

getSlidingMenu().setOnOpenListener(
new OnOpenListener() {
@Override
public void onOpen() {
frameLayout.setVisibility(View.GONE);
}
});


getSlidingMenu().setOnClosedListener(
new OnClosedListener() {


@Override
public void onClosed() {
frameLayout.setVisibility(View.VISIBLE);
}
});

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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.

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None of the methods above worked for me, not even others I've found elsewhere. Finally, I chose a partial solution. I listen on page changes via the ViewPager's onPageChangeListener, and hide the map when its page starts scrolling, and likewise show it again when it stops scrolling. I also have added a white View to be displayed when scrolling.

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My workaround: make use of the new snapshot interface from GoogleMap and display a snapshot of the map while scrolling the page.

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.

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Just copy my custom map fragment to your project. And if you have black lines with ScrollView on top and bottom set to your ScrollView android:fadingEdge="none"

public class CustomMapFragment extends SupportMapFragment {
private OnActivityCreatedListener onActivityCreatedListener;


public CustomMapFragment() {
}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup view, Bundle savedInstance) {
View layout = super.onCreateView(inflater, view, savedInstance);


FrameLayout frameLayout = new FrameLayout(getActivity());
frameLayout.setBackgroundColor(getResources().getColor(android.R.color.transparent));
((ViewGroup) layout).addView(frameLayout,
new ViewGroup.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
return layout;
}


@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (getOnActivityCreatedListener() != null)
getOnActivityCreatedListener().onCreated();
}


public OnActivityCreatedListener getOnActivityCreatedListener() {
return onActivityCreatedListener;
}


public void setOnActivityCreatedListener(
OnActivityCreatedListener onActivityCreatedListener) {
this.onActivityCreatedListener = onActivityCreatedListener;
}


public interface OnActivityCreatedListener {
void onCreated();
}

}

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Google released a fix for this, but only for 4.1+ (You don't need to download a new version of PlayServices, they used a server side flag)

Here's what I'm using to bypass the issue - Ensures you don't waste any CPU cycles on devices >= 4.1

public class FixMapFragment extends SupportMapFragment {


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


View view = super.onCreateView(inflater, container, savedInstanceState);


// Fix for black background on devices < 4.1
if (android.os.Build.VERSION.SDK_INT <
android.os.Build.VERSION_CODES.JELLY_BEAN) {
setMapTransparent((ViewGroup) view);
}
return view;
}


private void setMapTransparent(ViewGroup group) {
int childCount = group.getChildCount();
for (int i = 0; i < childCount; i++) {
View child = group.getChildAt(i);
if (child instanceof ViewGroup) {
setMapTransparent((ViewGroup) child);
} else if (child instanceof SurfaceView) {
child.setBackgroundColor(0x00000000);
}
}
}
}