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I am creating a custom view in android application. Custom view has Drawable object that is a vector image and is stored in folder res/drawable/ I want to save its state, so I create class SavedState that I use in methods onSaveInstanceState and onRestoreInstanceState.

private static class SavedState extends BaseSavedState {
        Drawable picture;
        Float degree = 0f;

        public SavedState(Parcelable superState) {
            super(superState);
        }

        public SavedState(Parcel source) {
            super(source);
            degree = source.readFloat();
            picture= = source.readParcelable(getClass().getClassLoader());
        }

        @Override
        public void writeToParcel(Parcel out, int flags) {
            super.writeToParcel(out, flags);
            out.writeFloat(degree);
            out.writeParcelable((Parcelable) fly, flags);
        }

        public static final Parcelable.Creator<SavedState> CREATOR
                = new Parcelable.Creator<SavedState>() {
            public SavedState createFromParcel(Parcel in) {
                return new SavedState(in);
            }

            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }

    @Nullable
    @Override
    protected Parcelable onSaveInstanceState() {
        Parcelable superState = super.onSaveInstanceState();
        SavedState myState = new SavedState(superState);
        myState.degree = this.degree;
        myState.picture = this.picture;
        return myState;
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        SavedState savedState = (SavedState) state;
        super.onRestoreInstanceState(savedState.getSuperState());
        this.degree = savedState.degree;
        this. picture = savedState. picture;
        invalidate();
    }

However, when I launch the app and flip the phone screen, an error occurs:
java.lang.ClassCastException: android.graphics.drawable.VectorDrawable cannot be cast to android.os.Parcelable. I have Android API 32 and Java 8.

I have tried to convert Drawable to Bitmap:

protected Parcelable onSaveInstanceState() {
// do not change the rest of the code
   Bitmap bitmap = source.readParcelable(getClass().getClassLoader());
   picture = new BitmapDrawable(bitmap); 
}

public void writeToParcel(Parcel out, int flags) {
// do not change the rest of the code
   Bitmap bitmap = ((BitmapDrawable) picture).getBitmap();
   out.writeParcelable(bitmap, flags);
}

But the error remained, only now Drawable could not be cast to BitmapDrawable.

I have also tried to save the id of my Drawable object. But I can't use the method getResources a static context:

picture = getResources().getDrawable(id)

Maybe there is another way to save the Drawable object?

sh_nadegda
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1 Answers1

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There is no safe way to convert a Drawable object into a Parcelable object in Java. And so, try not to save Drawable object in your custom view. Saving the state should still work correctly.

Qulanazes
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  • Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Nov 26 '22 at 17:17