Quelle  QRCodePopup.java

package ch.threema.app.ui;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.view.animation.AnimationSet;
import android.view.animation.DecelerateInterpolator;
import android.view.animation.ScaleAnimation;
import android.widget.ImageView;
import android.widget.PopupWindow;

import org.koin.java.KoinJavaComponent;
import org.slf4j.Logger;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.lifecycle.DefaultLifecycleObserver;
import androidx.lifecycle.LifecycleOwner;
import ch.threema.app.R;
import ch.threema.app.qrcodes.ContactUrlUtil;
import ch.threema.app.qrcodes.QrCodeGenerator;
import ch.threema.app.services.UserService;
import ch.threema.app.utils.AnimationUtil;
import static ch.threema.base.utils.LoggingKt.getThreemaLogger;

public class QRCodePopup extends DimmingPopupWindow implements DefaultLifecycleObserver {
    private static final Logger logger = getThreemaLogger("QRCodePopup");

    private ImageView imageView;
    private View topLayout;
    private View parentView;

    private final int[] location = new int[2];

    private @Nullable Bitmap bitmap;

    public QRCodePopup(Context context, View parentView, LifecycleOwner lifecycleOwner) {
        super(context);

        if (lifecycleOwner != null) {
            lifecycleOwner.getLifecycle().addObserver(this);
        }

        init(context, parentView);
    }

    private void init(@NonNull Context context, View parentView) {
        this.parentView = parentView;

        LayoutInflater layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        topLayout = layoutInflater.inflate(R.layout.popup_qrcode, null, true);

        this.imageView = topLayout.findViewById(R.id.thumbnail_view);

        setContentView(topLayout);

        setWidth(ViewGroup.LayoutParams.MATCH_PARENT);
        setHeight(ViewGroup.LayoutParams.MATCH_PARENT);

        setBackgroundDrawable(new BitmapDrawable());
        setAnimationStyle(0);
        setElevation(0);
        setInputMethodMode(PopupWindow.INPUT_METHOD_NOT_NEEDED);
    }

    /**
     * Show a popup with a QR code
     *
     * @param sourceView  starting point for animation
     * @param text        text to display as QR code, or null to display a QR code for the user's identity and public key
     */
    public void show(@NonNull final View sourceView, @Nullable String text) {
        QrCodeGenerator qrCodeGenerator = KoinJavaComponent.get(QrCodeGenerator.class);

        if (text != null) {
            bitmap = qrCodeGenerator.generateWithUnicodeSupport(text);
        } else {
            UserService userService = KoinJavaComponent.get(UserService.class);
            ContactUrlUtil contactUrlUtil = KoinJavaComponent.get(ContactUrlUtil.class);
            var content = contactUrlUtil.generate(
                userService.getIdentity(),
                userService.getPublicKey()
            );
            bitmap = qrCodeGenerator.generate(content);
        }

        if (bitmap == null) {
            logger.debug("Unable to get qr code bitmap");
            return;
        }

        final BitmapDrawable bitmapDrawable = new BitmapDrawable(getContext().getResources(), bitmap);
        bitmapDrawable.setFilterBitmap(false);

        this.imageView.setImageDrawable(bitmapDrawable);
        showAtLocation(parentView, Gravity.CENTER, 0, 0);
        dimBackground();

        getContentView().getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                getContentView().getViewTreeObserver().removeOnGlobalLayoutListener(this);

                AnimationUtil.getViewCenter(sourceView, getContentView(), location);

                AnimationSet animation = new AnimationSet(true);
                Animation scale = new ScaleAnimation(0.0f, 1.0f, 0.0f, 1.0f, Animation.ABSOLUTE, location[0], Animation.ABSOLUTE, location[1]);
                Animation fade = new AlphaAnimation(0.0f, 1.0f);

                animation.addAnimation(scale);
                animation.addAnimation(fade);
                animation.setInterpolator(new DecelerateInterpolator());
                animation.setDuration(150);

                getContentView().startAnimation(animation);
            }
        });

        topLayout.setOnClickListener(v -> dismiss());
    }

    @Override
    public void dismiss() {
        AnimationUtil.popupAnimateOut(getContentView(), () -> {
            QRCodePopup.super.dismiss();
            if (bitmap != null) {
                bitmap.recycle();
                bitmap = null;
            }
        });
    }

    /**
     * Notifies that {@code ON_PAUSE} event occurred.
     * <p>
     * This method will be called before the {@link LifecycleOwner}'s {@code onPause} method
     * is called.
     *
     * @param owner the component, whose state was changed
     */
    @Override
    public void onPause(@NonNull LifecycleOwner owner) {
        QRCodePopup.super.dismiss();
    }
}