Add in-app image viewer with swipe navigation

src/main/AndroidManifest.xml

@@ -380,6 +380,9 @@
         <activity
             android:name=".ui.ViewProfilePictureActivity"
             android:theme="@style/Theme.Conversations3.Dark" />
+        <activity
+            android:name=".ui.MediaViewerActivity"
+            android:theme="@style/Theme.Conversations3.Dark" />
         <activity
             android:name=".ui.MucUsersActivity"
             android:label="@string/group_chat_members" />

src/main/java/eu/siacs/conversations/ui/MediaViewerActivity.java

@@ -0,0 +1,142 @@
+package eu.siacs.conversations.ui;
+
+import android.graphics.Color;
+import android.net.Uri;
+import android.os.Bundle;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ImageView;
+import androidx.databinding.DataBindingUtil;
+import androidx.viewpager.widget.PagerAdapter;
+import androidx.viewpager.widget.ViewPager;
+import eu.siacs.conversations.R;
+import eu.siacs.conversations.databinding.ActivityMediaViewerBinding;
+import eu.siacs.conversations.entities.Conversation;
+import eu.siacs.conversations.entities.Message;
+import java.util.ArrayList;
+import java.util.List;
+
+public class MediaViewerActivity extends XmppActivity {
+
+    public static final String EXTRA_MESSAGE_UUID =
+            "eu.siacs.conversations.extra.MESSAGE_UUID";
+
+    private ActivityMediaViewerBinding binding;
+    private String conversationUuid;
+    private String messageUuid;
+
+    @Override
+    protected void onCreate(final Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+        this.binding =
+                DataBindingUtil.setContentView(this, R.layout.activity_media_viewer);
+        Activities.setStatusAndNavigationBarColors(this, binding.getRoot(), false, false);
+        setSupportActionBar(binding.toolbar);
+        configureActionBar(getSupportActionBar());
+        final var intent = getIntent();
+        if (intent != null) {
+            this.conversationUuid = intent.getStringExtra(ConversationsActivity.EXTRA_CONVERSATION);
+            this.messageUuid = intent.getStringExtra(EXTRA_MESSAGE_UUID);
+        }
+    }
+
+    @Override
+    protected void refreshUiReal() {}
+
+    @Override
+    protected void onBackendConnected() {
+        if (conversationUuid == null) {
+            return;
+        }
+        final Conversation conversation =
+                xmppConnectionService.findConversationByUuidReliable(conversationUuid);
+        if (conversation == null) {
+            return;
+        }
+        final List<Message> allMessages = new ArrayList<>();
+        conversation.populateWithMessages(allMessages);
+        final List<Message> images = new ArrayList<>();
+        for (final Message message : allMessages) {
+            if (isViewableImage(message)) {
+                images.add(message);
+            }
+        }
+        if (images.isEmpty()) {
+            return;
+        }
+        int startIndex = 0;
+        for (int i = 0; i < images.size(); i++) {
+            if (images.get(i).getUuid().equals(messageUuid)) {
+                startIndex = i;
+                break;
+            }
+        }
+        final int total = images.size();
+        final MediaPagerAdapter adapter = new MediaPagerAdapter(images);
+        binding.mediaPager.setAdapter(adapter);
+        binding.mediaPager.setCurrentItem(startIndex, false);
+        updateTitle(startIndex + 1, total);
+        binding.mediaPager.addOnPageChangeListener(
+                new ViewPager.SimpleOnPageChangeListener() {
+                    @Override
+                    public void onPageSelected(final int position) {
+                        updateTitle(position + 1, total);
+                    }
+                });
+    }
+
+    private void updateTitle(final int current, final int total) {
+        setTitle(current + " / " + total);
+    }
+
+    private static boolean isViewableImage(final Message message) {
+        if (!message.isFileOrImage()) {
+            return false;
+        }
+        if (message.getEncryption() == Message.ENCRYPTION_PGP) {
+            return false;
+        }
+        final Message.FileParams params = message.getFileParams();
+        return params.width > 0 && params.height > 0;
+    }
+
+    private class MediaPagerAdapter extends PagerAdapter {
+
+        private final List<Message> images;
+
+        MediaPagerAdapter(final List<Message> images) {
+            this.images = images;
+        }
+
+        @Override
+        public int getCount() {
+            return images.size();
+        }
+
+        @Override
+        public boolean isViewFromObject(final View view, final Object object) {
+            return view == object;
+        }
+
+        @Override
+        public Object instantiateItem(final ViewGroup container, final int position) {
+            final ImageView imageView = new ImageView(MediaViewerActivity.this);
+            imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
+            imageView.setBackgroundColor(Color.BLACK);
+            final Message message = images.get(position);
+            final var file =
+                    xmppConnectionService.getFileBackend().getFile(message);
+            if (file.exists()) {
+                imageView.setImageURI(Uri.fromFile(file));
+            }
+            container.addView(imageView);
+            return imageView;
+        }
+
+        @Override
+        public void destroyItem(
+                final ViewGroup container, final int position, final Object object) {
+            container.removeView((View) object);
+        }
+    }
+}

src/main/java/eu/siacs/conversations/ui/adapter/MessageAdapter.java

@@ -69,6 +69,7 @@
 import eu.siacs.conversations.ui.BindingAdapters;
 import eu.siacs.conversations.ui.ConversationFragment;
 import eu.siacs.conversations.ui.ConversationsActivity;
+import eu.siacs.conversations.ui.MediaViewerActivity;
 import eu.siacs.conversations.ui.XmppActivity;
 import eu.siacs.conversations.ui.service.AudioPlayer;
 import eu.siacs.conversations.ui.text.DividerSpan;
@@ -688,7 +689,7 @@ private void displayMediaPreviewMessage(
                 new LinearLayout.LayoutParams(scaledW, scaledH);
         viewHolder.image().setLayoutParams(layoutParams);
         activity.loadBitmap(message, viewHolder.image());
-        viewHolder.image().setOnClickListener(v -> openDownloadable(message));
+        viewHolder.image().setOnClickListener(v -> openMediaViewer(message));
     }
 
     private void toggleWhisperInfo(
@@ -1352,6 +1353,13 @@ public void openDownloadable(Message message) {
         ViewUtil.view(activity, file);
     }
 
+    private void openMediaViewer(final Message message) {
+        final Intent intent = new Intent(activity, MediaViewerActivity.class);
+        intent.putExtra(ConversationsActivity.EXTRA_CONVERSATION, message.getConversationUuid());
+        intent.putExtra(MediaViewerActivity.EXTRA_MESSAGE_UUID, message.getUuid());
+        activity.startActivity(intent);
+    }
+
     private void showLocation(Message message) {
         for (Intent intent : GeoHelper.createGeoIntentsFromMessage(activity, message)) {
             if (intent.resolveActivity(getContext().getPackageManager()) != null) {

src/main/res/layout/activity_media_viewer.xml

@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8"?>
+<layout xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:fitsSystemWindows="true"
+        android:orientation="vertical">
+
+        <com.google.android.material.appbar.AppBarLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+
+            <com.google.android.material.appbar.MaterialToolbar
+                android:id="@+id/toolbar"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:minHeight="?attr/actionBarSize" />
+
+        </com.google.android.material.appbar.AppBarLayout>
+
+        <androidx.viewpager.widget.ViewPager
+            android:id="@+id/media_pager"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:background="@android:color/black" />
+
+    </LinearLayout>
+</layout>