what makes my map fragment loading slow?

问题

Performance Enhancement:

Previously I saved ALL images in drawable folder, this might be the reason why the map first loads slow, when draw the markers on screen, the image may not fit the screen size. Now I saved images in drawable-mdpi, drawable-hdpi and so on, the app works smoother than before. Hope it helps

Original Question:

I created a map in a fragment, the source code can be found below.

The map fragment is sluggish when the first time it loads. If I go any other fragment and click the map fragment again, it loads fast and no slug anymore.

Can anyone tell me what is going on here? Thanks!

fragment_map.xml, id is map

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
          xmlns:map="http://schemas.android.com/apk/res-auto"
          android:id="@+id/map"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:name="com.google.android.gms.maps.SupportMapFragment"/>

MyMapFragment.java (contains onCreateView and setUpMapIfNeeded)

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    try {
        rootView = inflater.inflate(R.layout.fragment_map, container, false);
    } catch (InflateException e) {
    /* map is already there, just return view as it is */
        Log.e(TAG, "inflateException");
    }

     setUpMapIfNeeded();

    return rootView;
}


public void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the fragment_map.
        if (myMap == null) {
            // Try to obtain the fragment_map from the SupportMapFragment.
            myMap = ((SupportMapFragment) MainActivity.fragmentManager.findFragmentById(R.id.map)).getMap();
            // Check if we were successful in obtaining the fragment_map.
            if (myMap != null) {
                setUpMap();
            }
        }
    }

回答1:

I'm using a very hackish but effective way in my application, but it works good. My mapFragment is not displayed right after the app launches! Otherwise this would not make sense.

Put this in your launcher activity's onCreate:

    // Fixing Later Map loading Delay
    new Thread(new Runnable() {
        @Override
        public void run() {
            try {
                MapView mv = new MapView(getApplicationContext());
                mv.onCreate(null);
                mv.onPause();
                mv.onDestroy();
            }catch (Exception ignored){

            }
        }
    }).start();

This will create a mapview in an background thread (far away from the ui) and with it, initializes all the google play services and map data.

The loaded data is about 5MB extra.

If someone has some ideas for improvements feel free to comment please !

Java 8 Version:

// Fixing Later Map loading Delay
new Thread(() -> {
    try {
        MapView mv = new MapView(getApplicationContext());
        mv.onCreate(null);
        mv.onPause();
        mv.onDestroy();
    }catch (Exception ignored){}
}).start();

回答2:

Just to add to @Xyaren's answer, I needed it to work for SupportFragment which seemed to require some extra steps. Have your activity implement OnMapReadyCallback.

In your onCreate:

 new Thread(() -> {
        try {
            SupportMapFragment mf = SupportMapFragment.newInstance();
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.dummy_map_view, mf)
                    .commit();
            runOnUiThread(() -> mf.getMapAsync(SplashActivity.this));
        }catch (Exception ignored){
            Timber.w("Dummy map load exception: %s", ignored);
        }
    }).start();

You'll have to implement this:

@Override
 public void onMapReady(GoogleMap googleMap) {
    // Do nothing because we only want to pre-load map.
    Timber.d("Map loaded: %s", googleMap);
}

and in your activity layout:

<FrameLayout
    android:id="@+id/dummy_map_view"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:visibility="gone"/>

It needs to go through all the steps including the transaction for Google Play Services to download the map data.

回答3:

I had been running into this problem a lot too... Turns out the biggest culprit was having a debugging session attached to my app's process. The maps stuff in my app ran much faster and more smoothly when I disconnected the debugger, or just unplugged the USB cable.

Check out my related post here: First launch of Activity with Google Maps is very slow

回答4:

[EDITED]

The getMap() and setUpMap() methods are probably very slow. Their processing should be done in an AsyncTask so that onCreateView() can return quickly every time.

More info: onCreateView() is called on the UI thread, so any slow processing that it does will freeze the UI. Your AsyncTask should do all the slow processing in its doInBackground() method, and then update the UI in its onPostExecute() method. See the AsyncTask JavaDoc for more details.

回答5:

You could try this

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.mapActivity);
    getSreenDimanstions();
    fragment = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map));

    map = fragment.getMap();

}

This class extended Activity

来源：https://stackoverflow.com/questions/26265526/what-makes-my-map-fragment-loading-slow

标签

android

android-maps-v2

android-maps