Android – Prevent white screen at startup

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As we all know, many Android apps display a white screen very briefly before their first Activity comes into focus. This problem is observed in the following cases:

  • Android apps that extend the global Application class and perform major initializations therein. The Application object is always created before the first Activity (a fact that can be observed in the debugger), so this makes sense. This is the cause of the delay in my case.

  • Android apps that display the default preview window before the splash screen.

Setting android:windowDisablePreview = "true" obviously does not work here. Nor can I set the parent theme of the splash screen to Theme.Holo.NoActionBar as described here, because [unfortunately] my splash screen makes use of an ActionBar.

Meanwhile, apps that do not extend the Application class do not show the white screen at startup.

The thing is, ideally the initializations performed in the Application object need to occur before the first Activity is shown. So my question is, how can I perform these initializations on app startup without using an Application object? Possibly using a Thread or Service, I suppose?

This is an interesting problem to think about. I can’t bypass it the usual way (by setting the NoActionBar theme), as tragically my Splash screen actually has an ActionBar due to some unrelated reasons.

Note:

I have already referred to the following questions:

References:

Answer

The problem with white background is caused because of android’s cold start while the app loads to memory, and it can be avoided with this:

public class OnboardingWithCenterAnimationActivity extends AppCompatActivity {
public static final int STARTUP_DELAY = 300;
public static final int ANIM_ITEM_DURATION = 1000;
public static final int ITEM_DELAY = 300;

private boolean animationStarted = false;

@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    setTheme(R.style.AppTheme);
    getWindow().getDecorView().setSystemUiVisibility(
            View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_onboarding_center);
}

@Override
public void onWindowFocusChanged(boolean hasFocus) {

    if (!hasFocus || animationStarted) {
        return;
    }

    animate();

    super.onWindowFocusChanged(hasFocus);
}

private void animate() {
    ImageView logoImageView = (ImageView) findViewById(R.id.img_logo);
    ViewGroup container = (ViewGroup) findViewById(R.id.container);

    ViewCompat.animate(logoImageView)
        .translationY(-250)
        .setStartDelay(STARTUP_DELAY)
        .setDuration(ANIM_ITEM_DURATION).setInterpolator(
            new DecelerateInterpolator(1.2f)).start();

    for (int i = 0; i < container.getChildCount(); i++) {
        View v = container.getChildAt(i);
        ViewPropertyAnimatorCompat viewAnimator;

        if (!(v instanceof Button)) {
            viewAnimator = ViewCompat.animate(v)
                    .translationY(50).alpha(1)
                    .setStartDelay((ITEM_DELAY * i) + 500)
                    .setDuration(1000);
        } else {
            viewAnimator = ViewCompat.animate(v)
                    .scaleY(1).scaleX(1)
                    .setStartDelay((ITEM_DELAY * i) + 500)
                    .setDuration(500);
        }

        viewAnimator.setInterpolator(new DecelerateInterpolator()).start();
    }
}
}

layout

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="?colorPrimary"
android:orientation="vertical"
>

<LinearLayout
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:gravity="center"
    android:orientation="vertical"
    android:paddingTop="144dp"
    tools:ignore="HardcodedText"
    >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="16dp"
        android:alpha="0"
        android:text="Hello world"         android:textAppearance="@style/TextAppearance.AppCompat.Widget.ActionBar.Title.Inverse"
        android:textColor="@android:color/white"
        android:textSize="22sp"
        tools:alpha="1"
        />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="8dp"
        android:alpha="0"
        android:gravity="center"
        android:text="This a nice text"
      android:textAppearance="@style/TextAppearance.AppCompat.Widget.ActionBar.Subtitle.Inverse"
        android:textSize="20sp"
        tools:alpha="1"
        />

    <Button
        android:id="@+id/btn_choice1"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="48dp"
        android:scaleX="0"
        android:scaleY="0"
        android:text="A nice choice"
        android:theme="@style/Button"
        />

    <Button
        android:id="@+id/btn_choice2"
        android:layout_width="200dp"
        android:layout_height="wrap_content"
        android:layout_marginTop="4dp"
        android:scaleX="0"
        android:scaleY="0"
        android:text="Far better!"
        android:theme="@style/Button"
        />

</LinearLayout>

<ImageView
    android:id="@+id/img_logo"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    android:src="@drawable/img_face"
    tools:visibility="gone"
    />
</FrameLayout>

img face

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android"
        android:opacity="opaque">

<item android:drawable="?colorPrimary"/>
<item>
    <bitmap
        android:gravity="center"
        android:src="@drawable/img_face"/>
</item>

Add this theme to your splashscreen in the manifest

<?xml version="1.0" encoding="utf-8"?>
<resources>
<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
    <!-- Customize your theme here. -->
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
    <item name="android:windowBackground">@null</item>
</style>

<style name="AppTheme.CenterAnimation">
    <item name="android:windowBackground">@drawable/ll_face_logo</item>
</style>

which will produce efect like this

a busy cat

for more details and more solutions you can check this BlogPost



Source: stackoverflow