32
votes

We know that when the app do some long process like downloading some information from internet it could show a splash screen before loading the application and when the app is loaded completely it will display the main page. In splash screen activity we must load long processes in threads to avoid showing black screen before loading app. I had done all of them. but also the black screen appears before showing app. This is my onCreate method of the splash screen activity:

    protected override void OnCreate (Bundle bundle)
    {
        try {
            base.OnCreate (bundle);
            //_dt = DateTime.Now.AddSeconds (_splashTime);
            SetContentView (Resource.Layout.Splash );
            FirstLoadPB= FindViewById <ProgressBar >(Resource .Id.FirstLoadPB );
            FirstLoadingInfo= FindViewById <TextView >(Resource .Id.FirstLoadInfo );
            LoadApplication ();

        } catch (System.Exception ex) {

            Common.HandleException (ex);
        }
    }

and this is the code of LoadApplication method:

public void LoadApplication()
    {
        new System.Threading.Thread (new ThreadStart (() =>
                                                      {
        //Some Codes to load applications- Downloading from web and accessing the storage(Because was many codes - about 100 line- i was clear them.

        }
        )
                                     ).Start ();
    }

I don't understand why the black screen appears and how should to avoid from this now. I have some code that access to storage in oncreate of my application class. Maybe the issue's root cause be from there.There fore i shared its code:

public override void OnCreate ()
    {
        try {
            base.OnCreate ();
            _typeOfShow = new MapViewType ();
            ListingTypes = new Dictionary<int,ListingTypeItem> ();

            OfflineMode =false;
            PropertyShowWasShown = false;
            MeasutingUnitsChanged =false;
            if(RplXmlSettings .Instance .getVal (AppConstants .XmlSettingShowOnCurrentLocationKey  )== "True")
                typeOfShow .ShowOnCurrentLocation =true ;
            else
                typeOfShow .ShowOnCurrentLocation =false;
            //StorageClass .ctx = ApplicationContext ;
            FillDashboardOnResume =false;
            //initlize image loader 
            ImageLoader = Com.Nostra13.Universalimageloader.Core.ImageLoader.Instance;
            Options = new DisplayImageOptions.Builder ()
                .ShowImageForEmptyUri (Resource.Drawable.ic_tab_map)
                    .CacheOnDisc ()
                    .CacheInMemory ()
                    .ImageScaleType (ImageScaleType.InSampleInt)
                    .BitmapConfig (Bitmap.Config.Rgb565)
                    .Displayer (new FadeInBitmapDisplayer (300))
                    .Build ();
            ImageLoaderConfiguration config;

            ImageLoaderConfiguration .Builder builder =new ImageLoaderConfiguration
                .Builder (ApplicationContext).ThreadPoolSize (3);

            if(RplXmlSettings .Instance .getVal (AppConstants .XmlSettingMemoryCacheKey )== "True")
                builder .ThreadPriority (4).MemoryCacheSize (1500000) ;// 1.5 Mb

            builder .
                DenyCacheImageMultipleSizesInMemory ().
                    DiscCacheFileNameGenerator (new Md5FileNameGenerator ()).
                    MemoryCache (new WeakMemoryCache()).
                    DiscCacheSize (15000000);
            config = builder .Build ();
            ImageLoader.Init (config);

        } catch (Exception ex) {
            Common .HandleException (ex);
        }

    }

OK.Long story short.Now the question is this-- Really what is the root cause of this black screen. Is this from splash activity or from application class. And How we can solve it and avoid form showing this?

7
If you don't set a custom theme with your own background for your application, the android default theme will be drawn with a black background first, before your background, see my answer.TouchBoarder

7 Answers

69
votes

Add a theme with the background you are using to your application tag in the manifest file to prevent the black screen to be drawn.

theme.xml

<resources>
<!-- Base application theme is the default theme. -->
<style name="Theme" parent="android:style/Theme" />

<style name="Theme.MyAppTheme" parent="Theme">
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:windowBackground">@drawable/my_app_background</item>

</style>
</resources>

AndroidManifest.xml

....
<application
        android:name="@string/app_name"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/Theme.MyAppTheme"
         >
....

Read why there is a black screen here On app launch, Android displays a simple preview window (based on your activity theme) as an immediate response to the user action. Then the preview window crossfades with your actual UI, once that has fully loaded. To ensure a smooth visual transition, your activity theme should match your full UI as closely as possible. The below image shows how the experience can be jarring if not handled properly.

51
votes

This initial screen that you see is called the "Preview" screen. You can disable this completely by declaring this in your theme:

android:windowDisablePreview

<style name="Theme.MyTheme" parent="android:style/Theme.Holo">
    <!-- This disables the black preview screen -->
    <item name="android:windowDisablePreview">true</item>
</style>

An explanation of how to handle this screen is posted here: http://cyrilmottier.com/2013/01/23/android-app-launching-made-gorgeous/

9
votes

Add this line in your AndroidManifest.xml to the Launcher Activity:

android:theme="@android:style/Theme.Translucent.NoTitleBar.Fullscreen

2
votes

You can solve this bug by converting image as a brush(color).

Add new file xml(splash_bg.xml) file in the drawable folder, like this.

<?xml version="1.0" encoding="utf-8" ?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
   <item>
      <color android:color="@color/splash_bg_color"/>
   </item>
   <item>
        <bitmap
            android:src="@drawable/splash_screen"
            android:tileMode="disabled"
            android:gravity="center"/>
   </item>
</layer-list>

Now add a new style, and apply splash_bg.xml as a background color.

<style name="Theme.SplashBg" parent="android:Theme">
    <item name="android:windowBackground">@drawable/splash_bg</item>
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowContentOverlay">@null</item>
</style>

Apply this new style to your main launcher activity or splash screen.

[Activity(Label = "label", MainLauncher = true, Theme = "@style/Theme.SplashBg")]
public class SplashScreenActivity : Activity
1
votes

If you call some "heavy code" in onCreate the screen will appear black until it is done loading. You might consider using AsyncTask and make the onCreate handle setContentView etc, and make the AsyncTask handle "the heavy code".

1
votes

the better solution to avoid this problem is using AsyncTask, here is a sample code that i use in one of my ListActivity:

 private class YoutubeTask extends AsyncTask<URL, Integer, String> {
     protected void onPreExecute() {
            super.onPreExecute();
            mLoadingProgress.startAnimation(mDisappear);
        mLoadingProgress.setVisibility(View.GONE);
            showDialogProgress();
    }

     protected String doInBackground(URL... url) {

         youtubeData = VersionParser.readFromUrl(url[0]);;

        try {

            JSONObject jsono = new JSONObject(youtubeData);
            JSONObject feed = jsono.getJSONObject("feed");
            JSONArray entry = feed.getJSONArray("entry");

            for(int i = 0 ; i < entry.length() ; i++ ){

                JSONObject item = entry.getJSONObject(i);

                JSONArray AUTHOR = item.getJSONArray(TAG_AUTHOR);
                JSONObject Author = AUTHOR.getJSONObject(0);
                JSONObject author = Author.getJSONObject("name");
                String author_name = author.getString(TAG_TITRE);

                JSONObject Statistics = item.getJSONObject("yt$statistics");
                String Views = Statistics.getString(TAG_VIEWS);

                JSONObject Media = item.getJSONObject("media$group");

                JSONObject MediaTitle = Media.getJSONObject("media$title");
                String title = MediaTitle.getString(TAG_TITRE);

                JSONObject DURATION = Media.getJSONObject("yt$duration");
                String duration = DURATION.getString(TAG_DURATION);

                JSONArray Thumbinail = Media.getJSONArray("media$thumbnail");
                JSONObject IMAGE = Thumbinail.getJSONObject(0);
                String image = IMAGE.getString(TAG_CONTENT);
                String id = image.substring(22,33);

                 map = new HashMap<String, String>();

                    map.put(TAG_TITRE , title ); 
                    map.put(TAG_ID , id );
                    map.put(TAG_DURATION , duration );
                    map.put(TAG_IMAGE , image);
                    map.put(TAG_VIEWS , Views );
                    map.put(TAG_AUTHOR , author_name);

                   CURRENCY.add(map);
                }


        } catch (JSONException e) {

            e.printStackTrace();
        }
            return null;
        }


     @Override
        protected void onPostExecute(String result) { 

             dismisDialogProgress(); 
             mListView.setVisibility(View.VISIBLE);
            mListView.startAnimation(mAppear);
            mAdapter = new MAdapter(youtubeSearch.this , CURRENCY);
            mListView.setSelector(R.drawable.home_bg);
            mListView.setAdapter(mAdapter);

             } 
    }

and inside the onCreate Methode implement this:

            @Override

    public void onCreate(Bundle savedInstanceState) {

        if (Build.VERSION.SDK_INT < 11)
        setTheme(android.R.style.Theme_Black_NoTitleBar);
    }
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);


    new YoutubeTask().execute(new URL("https://gdata.youtube.com/feeds/api/videos?q=Adele&max-results=15&v=2&alt=json"));
        }
0
votes

Here's some food for thought; maybe you don't have a sizeable initialization delay in your application at all; you might in fact, be waiting for the instant run service.

From what I've experienced, the symptoms of this are that your application shows a lengthy black screen whilst initializing, but upon debugging you find that none of your Application/Activity's onCreate methods have yet to even be called whilst it's visible.