Fix IAE crash in link device transition.

app/src/main/java/org/thoughtcrime/securesms/DeviceAddFragment.java

@@ -14,12 +14,16 @@ import android.widget.ImageView;
 import android.widget.LinearLayout;
 
 import androidx.annotation.NonNull;
+import androidx.core.view.ViewCompat;
 
 import org.signal.qr.QrScannerView;
 import org.signal.qr.kitkat.ScanListener;
 import org.thoughtcrime.securesms.util.LifecycleDisposable;
 import org.thoughtcrime.securesms.util.ViewUtil;
 
+import io.reactivex.rxjava3.android.schedulers.AndroidSchedulers;
+import io.reactivex.rxjava3.disposables.Disposable;
+
 public class DeviceAddFragment extends LoggingFragment {
 
   private final LifecycleDisposable lifecycleDisposable = new LifecycleDisposable();
@@ -34,6 +38,7 @@ public class DeviceAddFragment extends LoggingFragment {
     this.overlay      = container.findViewById(R.id.overlay);
     QrScannerView scannerView = container.findViewById(R.id.scanner);
     this.devicesImage = container.findViewById(R.id.devices);
+    ViewCompat.setTransitionName(devicesImage, "devices");
 
     if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
       this.overlay.setOrientation(LinearLayout.HORIZONTAL);
@@ -61,11 +66,18 @@ public class DeviceAddFragment extends LoggingFragment {
     scannerView.start(getViewLifecycleOwner());
 
     lifecycleDisposable.bindTo(getViewLifecycleOwner());
-    lifecycleDisposable.add(scannerView.getQrData().subscribe(qrData -> {
+
-      if (scanListener != null) {
+    Disposable qrDisposable = scannerView
-        scanListener.onQrDataFound(qrData);
+        .getQrData()
-      }
+        .distinctUntilChanged()
-    }));
+        .observeOn(AndroidSchedulers.mainThread())
+        .subscribe(qrData -> {
+          if (scanListener != null) {
+            scanListener.onQrDataFound(qrData);
+          }
+        });
+
+    lifecycleDisposable.add(qrDisposable);
 
     return container;
   }

app/src/main/java/org/thoughtcrime/securesms/DeviceLinkFragment.java

@@ -9,6 +9,7 @@ import android.view.ViewGroup;
 import android.widget.LinearLayout;
 
 import androidx.annotation.NonNull;
+import androidx.core.view.ViewCompat;
 import androidx.fragment.app.Fragment;
 
 public class DeviceLinkFragment extends Fragment implements View.OnClickListener {
@@ -21,6 +22,7 @@ public class DeviceLinkFragment extends Fragment implements View.OnClickListener
   public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup viewGroup, Bundle bundle) {
     this.container = (LinearLayout) inflater.inflate(R.layout.device_link_fragment, container, false);
     this.container.findViewById(R.id.link_device).setOnClickListener(this);
+    ViewCompat.setTransitionName(container.findViewById(R.id.devices), "devices");
 
     if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
       container.setOrientation(LinearLayout.HORIZONTAL);

app/src/main/res/layout/device_add_fragment.xml

@@ -22,7 +22,6 @@
             android:layout_height="match_parent"
             android:layout_weight="1" />
 
-
         <LinearLayout
             android:layout_width="match_parent"
             android:layout_height="match_parent"
@@ -48,7 +47,6 @@
                 android:text="@string/device_add_fragment__scan_the_qr_code_displayed_on_the_device_to_link"
                 android:textColor="?android:textColorSecondary" />
 
-
         </LinearLayout>
     </LinearLayout>
 

app/src/main/res/layout/device_link_fragment.xml

@@ -6,6 +6,7 @@
               android:gravity="center">
 
     <androidx.appcompat.widget.AppCompatImageView
+            android:id="@+id/devices"
             android:layout_width="wrap_content"
             android:layout_height="wrap_content"
             android:src="@drawable/ic_devices_white"