Allow using lottie files for splashscreen (SDL2 bootstrap) (kivy#2296)

- add `--presplash-lottie` option to `build` command allowing to pass a
  json file
- add lottie to build.gradle if necessary
- use an xml layout file to define the view (added/removed appropriately
  by build.py)
- rework PythonActivity to select appropriate view at startup

Author: tshirtman

doc/source/buildoptions.rst

@@ -74,6 +74,8 @@ options (this list may not be exhaustive):
   the application is loading.
 - ``--presplash-color``: The presplash screen background color, of the
   form ``#RRGGBB`` or a color name ``red``, ``green``, ``blue`` etc.
+- ``--presplash-lottie``: use a lottie (json) file as a presplash animation. If
+  used, this will replace the static presplash image.
 - ``--wakelock``: If the argument is included, the application will
   prevent the device from sleeping.
 - ``--window``: If the argument is included, the application will not

pythonforandroid/bootstraps/common/build/build.py

@@ -326,11 +326,28 @@ def make_package(args):
         args.icon or default_icon,
         join(res_dir, 'drawable/icon.png')
     )
+
     if get_bootstrap_name() != "service_only":
-        shutil.copy(
-            args.presplash or default_presplash,
-            join(res_dir, 'drawable/presplash.jpg')
-        )
+        lottie_splashscreen = join(res_dir, 'raw/splashscreen.json')
+        if args.presplash_lottie:
+            shutil.copy(
+                'templates/lottie.xml',
+                join(res_dir, 'layout/lottie.xml')
+            )
+            ensure_dir(join(res_dir, 'raw'))
+            shutil.copy(
+                args.presplash_lottie,
+                join(res_dir, 'raw/splashscreen.json')
+            )
+        else:
+            if exists(lottie_splashscreen):
+                remove(lottie_splashscreen)
+                remove(join(res_dir, 'layout/lottie.xml'))
+
+            shutil.copy(
+                args.presplash or default_presplash,
+                join(res_dir, 'drawable/presplash.jpg')
+            )
 
     # If extra Java jars were requested, copy them into the libs directory
     jars = []
@@ -627,6 +644,9 @@ def parse_args_and_make_package(args=None):
         ap.add_argument('--presplash', dest='presplash',
                         help=('A jpeg file to use as a screen while the '
                               'application is loading.'))
+        ap.add_argument('--presplash-lottie', dest='presplash_lottie',
+                        help=('A lottie (json) file to use as an animation while the '
+                              'application is loading.'))
         ap.add_argument('--presplash-color',
                         dest='presplash_color',
                         default='#000000',

pythonforandroid/bootstraps/common/build/templates/build.tmpl.gradle

@@ -109,5 +109,8 @@ dependencies {
     implementation '{{ depend }}'
     {%- endfor %}
     {%- endif %}
+    {% if args.presplash_lottie %}
+    implementation 'com.airbnb.android:lottie:3.4.0'
+    {%- endif %}
 }
 

pythonforandroid/bootstraps/common/build/templates/lottie.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:orientation="vertical"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent"
+>
+
+    <com.airbnb.lottie.LottieAnimationView
+        android:id="@+id/progressBar"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_gravity="center"
+        android:scaleType="centerInside"
+        android:layout_weight="4"
+        app:lottie_autoPlay="true"
+        app:lottie_loop="true"
+        app:lottie_rawRes="@raw/splashscreen"
+    />
+</LinearLayout>
+

pythonforandroid/bootstraps/sdl2/build/src/main/java/org/kivy/android/PythonActivity.java

@@ -27,8 +27,10 @@
 import android.util.Log;
 import android.view.SurfaceView;
 import android.view.ViewGroup;
+import android.view.View;
 import android.widget.ImageView;
 import android.widget.Toast;
+import android.content.res.Resources.NotFoundException;
 
 import org.libsdl.app.SDLActivity;
 
@@ -61,7 +63,7 @@ protected void onCreate(Bundle savedInstanceState) {
         Log.v(TAG, "Did super onCreate");
 
         this.mActivity = this;
-        this.showLoadingScreen();
+        this.showLoadingScreen(this.getLoadingScreen());
 
         new UnpackFilesTask().execute(getAppRoot());
     }
@@ -121,7 +123,7 @@ protected void onPostExecute(String result) {
             // removed the loading screen. However, we still need it to
             // show until the app is ready to render, so pop it back up
             // on top of the SDL view.
-            mActivity.showLoadingScreen();
+            mActivity.showLoadingScreen(getLoadingScreen());
 
             String app_root_dir = getAppRoot();
             if (getIntent() != null && getIntent().getAction() != null &&
@@ -338,6 +340,7 @@ public static void stop_service() {
 
     /** Loading screen view **/
     public static ImageView mImageView = null;
+    public static View mLottieView = null;
     /** Whether main routine/actual app has started yet **/
     protected boolean mAppConfirmedActive = false;
     /** Timer for delayed loading screen removal. **/
@@ -404,11 +407,11 @@ public void run() {
     public void removeLoadingScreen() {
         runOnUiThread(new Runnable() {
             public void run() {
-                if (PythonActivity.mImageView != null && 
-                        PythonActivity.mImageView.getParent() != null) {
-                    ((ViewGroup)PythonActivity.mImageView.getParent()).removeView(
-                        PythonActivity.mImageView);
-                    PythonActivity.mImageView = null;
+                View view = mLottieView != null ? mLottieView : mImageView;
+                if (view != null && view.getParent() != null) {
+                    ((ViewGroup)view.getParent()).removeView(view);
+                    mLottieView = null;
+                    mImageView = null;
                 }
             }
         });
@@ -430,65 +433,97 @@ public String getEntryPoint(String search_dir) {
         return "main.py";
     }
 
-    protected void showLoadingScreen() {
+    protected void showLoadingScreen(View view) {
+        try {
+            if (mLayout == null) {
+                setContentView(view);
+            } else if (view.getParent() == null) {
+                mLayout.addView(view);
+            }
+        } catch (IllegalStateException e) {
+            // The loading screen can be attempted to be applied twice if app
+            // is tabbed in/out, quickly.
+            // (Gives error "The specified child already has a parent.
+            // You must call removeView() on the child's parent first.")
+        }
+    }
+
+    protected View getLoadingScreen() {
         // load the bitmap
         // 1. if the image is valid and we don't have layout yet, assign this bitmap
         // as main view.
         // 2. if we have a layout, just set it in the layout.
         // 3. If we have an mImageView already, then do nothing because it will have
         // already been made the content view or added to the layout.
 
-        if (mImageView == null) {
-            int presplashId = this.resourceManager.getIdentifier("presplash", "drawable");
-            InputStream is = this.getResources().openRawResource(presplashId);
-            Bitmap bitmap = null;
+        if (mLottieView != null || mImageView != null) {
+            // we already have a splash screen
+            return mLottieView != null ? mLottieView : mImageView;
+        }
+
+        // first try to load the lottie one
+        try {
+            mLottieView = getLayoutInflater().inflate(
+                this.resourceManager.getIdentifier("lottie", "layout"),
+                mLayout,
+                false
+            );
             try {
-                bitmap = BitmapFactory.decodeStream(is);
-            } finally {
-                try {
-                    is.close();
-                } catch (IOException e) {};
+                if (mLayout == null) {
+                    setContentView(mLottieView);
+                } else if (PythonActivity.mLottieView.getParent() == null) {
+                    mLayout.addView(mLottieView);
+                }
+            } catch (IllegalStateException e) {
+                // The loading screen can be attempted to be applied twice if app
+                // is tabbed in/out, quickly.
+                // (Gives error "The specified child already has a parent.
+                // You must call removeView() on the child's parent first.")
             }
-
-            mImageView = new ImageView(this);
-            mImageView.setImageBitmap(bitmap);
-
-            /*
-             * Set the presplash loading screen background color
-             * https://developer.android.com/reference/android/graphics/Color.html
-             * Parse the color string, and return the corresponding color-int.
-             * If the string cannot be parsed, throws an IllegalArgumentException exception.
-             * Supported formats are: #RRGGBB #AARRGGBB or one of the following names:
-             * 'red', 'blue', 'green', 'black', 'white', 'gray', 'cyan', 'magenta', 'yellow',
-             * 'lightgray', 'darkgray', 'grey', 'lightgrey', 'darkgrey', 'aqua', 'fuchsia',
-             * 'lime', 'maroon', 'navy', 'olive', 'purple', 'silver', 'teal'.
-             */
-            String backgroundColor = resourceManager.getString("presplash_color");
-            if (backgroundColor != null) {
-                try {
-                    mImageView.setBackgroundColor(Color.parseColor(backgroundColor));
-                } catch (IllegalArgumentException e) {}
-            }   
-            mImageView.setLayoutParams(new ViewGroup.LayoutParams(
-                ViewGroup.LayoutParams.FILL_PARENT,
-                ViewGroup.LayoutParams.FILL_PARENT));
-            mImageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
+            return mLottieView;
+        }
+        catch (NotFoundException e) {
+            Log.v("SDL", "couldn't find lottie layout or animation, trying static splash");
         }
 
+        // try to load the static image then
+        int presplashId = this.resourceManager.getIdentifier("presplash", "drawable");
+        InputStream is = this.getResources().openRawResource(presplashId);
+        Bitmap bitmap = null;
         try {
-            if (mLayout == null) {
-                setContentView(mImageView);
-            } else if (PythonActivity.mImageView.getParent() == null) {
-                mLayout.addView(mImageView);
-            }
-        } catch (IllegalStateException e) {
-            // The loading screen can be attempted to be applied twice if app
-            // is tabbed in/out, quickly.
-            // (Gives error "The specified child already has a parent.
-            // You must call removeView() on the child's parent first.")
+            bitmap = BitmapFactory.decodeStream(is);
+        } finally {
+            try {
+                is.close();
+            } catch (IOException e) {};
         }
+
+        mImageView = new ImageView(this);
+        mImageView.setImageBitmap(bitmap);
+
+        /*
+         * Set the presplash loading screen background color
+         * https://developer.android.com/reference/android/graphics/Color.html
+         * Parse the color string, and return the corresponding color-int.
+         * If the string cannot be parsed, throws an IllegalArgumentException exception.
+         * Supported formats are: #RRGGBB #AARRGGBB or one of the following names:
+         * 'red', 'blue', 'green', 'black', 'white', 'gray', 'cyan', 'magenta', 'yellow',
+         * 'lightgray', 'darkgray', 'grey', 'lightgrey', 'darkgrey', 'aqua', 'fuchsia',
+         * 'lime', 'maroon', 'navy', 'olive', 'purple', 'silver', 'teal'.
+         */
+        String backgroundColor = resourceManager.getString("presplash_color");
+        if (backgroundColor != null) {
+            try {
+                mImageView.setBackgroundColor(Color.parseColor(backgroundColor));
+            } catch (IllegalArgumentException e) {}
+        }
+        mImageView.setLayoutParams(new ViewGroup.LayoutParams(
+            ViewGroup.LayoutParams.FILL_PARENT,
+            ViewGroup.LayoutParams.FILL_PARENT));
+        mImageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
+        return mImageView;
     }
-    
+
     @Override
     protected void onPause() {
         if (this.mWakeLock != null && mWakeLock.isHeld()) {