[android] Swipe left/right in image screen to see other images from the same message

briar-android/src/main/java/org/briarproject/briar/android/activity/ActivityComponent.java

@@ -20,6 +20,7 @@ import org.briarproject.briar.android.contact.ContactModule;
 import org.briarproject.briar.android.conversation.AliasDialogFragment;
 import org.briarproject.briar.android.conversation.ConversationActivity;
 import org.briarproject.briar.android.conversation.ImageActivity;
+import org.briarproject.briar.android.conversation.ImageFragment;
 import org.briarproject.briar.android.forum.CreateForumActivity;
 import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.forum.ForumListFragment;
@@ -218,4 +219,6 @@ public interface ActivityComponent {
 
 	void inject(AliasDialogFragment aliasDialogFragment);
 
+	void inject(ImageFragment imageFragment);
+
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/AttachmentItem.java

@@ -2,6 +2,7 @@ package org.briarproject.briar.android.conversation;
 
 import android.os.Parcel;
 import android.os.Parcelable;
+import android.support.annotation.Nullable;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.bramble.api.sync.MessageId;
@@ -111,4 +112,10 @@ public class AttachmentItem implements Parcelable {
 		dest.writeByte((byte) (hasError ? 1 : 0));
 	}
 
+	@Override
+	public boolean equals(@Nullable Object o) {
+		return o instanceof AttachmentItem &&
+				messageId.equals(((AttachmentItem) o).messageId);
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationActivity.java

@@ -121,8 +121,9 @@ import static org.briarproject.bramble.util.StringUtils.isNullOrEmpty;
 import static org.briarproject.briar.android.TestingConstants.FEATURE_FLAG_IMAGE_ATTACHMENTS;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_ATTACH_IMAGE;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_INTRODUCTION;
-import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENT;
+import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENT_POSITION;
 import static org.briarproject.briar.android.conversation.ImageActivity.DATE;
+import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENTS;
 import static org.briarproject.briar.android.conversation.ImageActivity.NAME;
 import static org.briarproject.briar.android.settings.SettingsFragment.SETTINGS_NAMESPACE;
 import static org.briarproject.briar.android.util.UiUtils.getAvatarTransitionName;
@@ -812,8 +813,11 @@ public class ConversationActivity extends BriarActivity
 		} else {
 			name = getString(R.string.you);
 		}
+		ArrayList<AttachmentItem> attachments =
+				new ArrayList<>(messageItem.getAttachments());
 		Intent i = new Intent(this, ImageActivity.class);
-		i.putExtra(ATTACHMENT, item);
+		i.putParcelableArrayListExtra(ATTACHMENTS, attachments);
+		i.putExtra(ATTACHMENT_POSITION, attachments.indexOf(item));
 		i.putExtra(NAME, name);
 		i.putExtra(DATE, messageItem.getTime());
 		if (SDK_INT >= 23) {

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageActivity.java

@@ -4,15 +4,18 @@ import android.arch.lifecycle.ViewModelProvider;
 import android.arch.lifecycle.ViewModelProviders;
 import android.content.DialogInterface.OnClickListener;
 import android.content.Intent;
-import android.graphics.drawable.Animatable;
 import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.annotation.RequiresApi;
 import android.support.design.widget.AppBarLayout;
 import android.support.design.widget.Snackbar;
+import android.support.v4.app.Fragment;
+import android.support.v4.app.FragmentManager;
+import android.support.v4.app.FragmentStatePagerAdapter;
 import android.support.v4.content.ContextCompat;
 import android.support.v4.graphics.drawable.DrawableCompat;
+import android.support.v4.view.ViewPager;
 import android.support.v7.app.AlertDialog.Builder;
 import android.support.v7.widget.Toolbar;
 import android.transition.Fade;
@@ -20,23 +23,18 @@ import android.transition.Transition;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
+import android.view.ViewTreeObserver.OnGlobalLayoutListener;
 import android.view.Window;
 import android.widget.TextView;
 
-import com.bumptech.glide.load.DataSource;
-import com.bumptech.glide.load.engine.GlideException;
-import com.bumptech.glide.request.RequestListener;
-import com.bumptech.glide.request.target.Target;
-import com.github.chrisbanes.photoview.PhotoView;
-
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
-import org.briarproject.briar.android.conversation.glide.GlideApp;
 import org.briarproject.briar.android.view.PullDownLayout;
 
 import java.text.SimpleDateFormat;
 import java.util.Date;
+import java.util.List;
 import java.util.Locale;
 
 import javax.inject.Inject;
@@ -53,16 +51,15 @@ import static android.view.View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN;
 import static android.view.View.SYSTEM_UI_FLAG_LAYOUT_STABLE;
 import static android.view.View.VISIBLE;
 import static android.view.WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS;
-import static android.widget.ImageView.ScaleType.FIT_START;
-import static com.bumptech.glide.load.engine.DiskCacheStrategy.NONE;
 import static java.util.Objects.requireNonNull;
 import static org.briarproject.briar.android.activity.RequestCodes.REQUEST_SAVE_ATTACHMENT;
 import static org.briarproject.briar.android.util.UiUtils.formatDateAbsolute;
 
 public class ImageActivity extends BriarActivity
-		implements PullDownLayout.Callback {
+		implements PullDownLayout.Callback, OnGlobalLayoutListener {
 
-	final static String ATTACHMENT = "attachment";
+	final static String ATTACHMENTS = "attachments";
+	final static String ATTACHMENT_POSITION = "position";
 	final static String NAME = "name";
 	final static String DATE = "date";
 
@@ -72,8 +69,8 @@ public class ImageActivity extends BriarActivity
 	private ImageViewModel viewModel;
 	private PullDownLayout layout;
 	private AppBarLayout appBarLayout;
-	private PhotoView photoView;
-	private AttachmentItem attachment;
+	private ViewPager viewPager;
+	private List<AttachmentItem> attachments;
 
 	@Override
 	public void injectActivity(ActivityComponent component) {
@@ -102,6 +99,7 @@ public class ImageActivity extends BriarActivity
 		layout = findViewById(R.id.layout);
 		layout.getBackground().setAlpha(255);
 		layout.setCallback(this);
+		layout.getViewTreeObserver().addOnGlobalLayoutListener(this);
 
 		// Status Bar
 		if (SDK_INT >= 21) {
@@ -118,59 +116,29 @@ public class ImageActivity extends BriarActivity
 		TextView dateView = toolbar.findViewById(R.id.dateView);
 
 		// Intent Extras
-		attachment = getIntent().getParcelableExtra(ATTACHMENT);
-		String name = getIntent().getStringExtra(NAME);
-		long time = getIntent().getLongExtra(DATE, 0);
+		Intent i = getIntent();
+		attachments = i.getParcelableArrayListExtra(ATTACHMENTS);
+		int position = i.getIntExtra(ATTACHMENT_POSITION, -1);
+		if (position == -1) throw new IllegalStateException();
+		String name = i.getStringExtra(NAME);
+		long time = i.getLongExtra(DATE, 0);
 		String date = formatDateAbsolute(this, time);
 		contactName.setText(name);
 		dateView.setText(date);
 
-		// Image View
-		photoView = findViewById(R.id.photoView);
+		// Set up image ViewPager
+		viewPager = findViewById(R.id.viewPager);
+		ImagePagerAdapter pagerAdapter =
+				new ImagePagerAdapter(getSupportFragmentManager());
+		viewPager.setAdapter(pagerAdapter);
+		viewPager.setCurrentItem(position);
+
 		if (SDK_INT >= 16) {
-			photoView.setOnClickListener(view -> toggleSystemUi());
+			viewModel.getOnImageClicked().observe(this, this::onPhotoClicked);
 			window.getDecorView().setSystemUiVisibility(
 					SYSTEM_UI_FLAG_LAYOUT_STABLE |
 							SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
 		}
-
-		// Request Listener
-		RequestListener<Drawable> listener = new RequestListener<Drawable>() {
-			@Override
-			public boolean onLoadFailed(@Nullable GlideException e,
-					Object model, Target<Drawable> target,
-					boolean isFirstResource) {
-				supportStartPostponedEnterTransition();
-				return false;
-			}
-
-			@Override
-			public boolean onResourceReady(Drawable resource, Object model,
-					Target<Drawable> target, DataSource dataSource,
-					boolean isFirstResource) {
-				if (SDK_INT >= 21 && !(resource instanceof Animatable)) {
-					// set transition name only when not animatable,
-					// because the animation won't start otherwise
-					photoView.setTransitionName(
-							attachment.getTransitionName());
-				}
-				// Move image to the top if overlapping toolbar
-				if (isOverlappingToolbar(resource)) {
-					photoView.setScaleType(FIT_START);
-				}
-				supportStartPostponedEnterTransition();
-				return false;
-			}
-		};
-
-		// Load Image
-		GlideApp.with(this)
-				.load(attachment)
-				.diskCacheStrategy(NONE)
-				.error(R.drawable.ic_image_broken)
-				.dontTransform()
-				.addListener(listener)
-				.into(photoView);
 	}
 
 	@Override
@@ -193,11 +161,21 @@ public class ImageActivity extends BriarActivity
 		}
 	}
 
+	@Override
+	public void onGlobalLayout() {
+		viewModel.setToolbarPosition(
+				appBarLayout.getTop(), appBarLayout.getBottom()
+		);
+		if (SDK_INT >= 16) {
+			layout.getViewTreeObserver().removeOnGlobalLayoutListener(this);
+		}
+	}
+
 	@Override
 	protected void onActivityResult(int request, int result, Intent data) {
 		super.onActivityResult(request, result, data);
 		if (request == REQUEST_SAVE_ATTACHMENT && result == RESULT_OK) {
-			viewModel.saveImage(attachment, data.getData());
+			viewModel.saveImage(getVisibleAttachment(), data.getData());
 		}
 	}
 
@@ -225,6 +203,13 @@ public class ImageActivity extends BriarActivity
 		supportFinishAfterTransition();
 	}
 
+	private void onPhotoClicked(@Nullable Boolean clicked) {
+		if (clicked != null&& clicked && SDK_INT >= 16) {
+			toggleSystemUi();
+			viewModel.onOnImageClickSeen();
+		}
+	}
+
 	@RequiresApi(api = 16)
 	private void toggleSystemUi() {
 		View decorView = getWindow().getDecorView();
@@ -259,29 +244,13 @@ public class ImageActivity extends BriarActivity
 				.start();
 	}
 
-	private boolean isOverlappingToolbar(Drawable drawable) {
-		int width = drawable.getIntrinsicWidth();
-		int height = drawable.getIntrinsicHeight();
-		float widthPercentage = photoView.getWidth() / (float) width;
-		float heightPercentage = photoView.getHeight() / (float) height;
-		float scaleFactor = Math.min(widthPercentage, heightPercentage);
-		int realWidth = (int) (width * scaleFactor);
-		int realHeight = (int) (height * scaleFactor);
-		// return if photo doesn't use the full width,
-		// because it will be moved to the right otherwise
-		if (realWidth < photoView.getWidth()) return false;
-		int drawableTop = (photoView.getHeight() - realHeight) / 2;
-		return drawableTop < appBarLayout.getBottom() &&
-				drawableTop != appBarLayout.getTop();
-	}
-
 	private void showSaveImageDialog() {
 		OnClickListener okListener = (dialog, which) -> {
 			if (SDK_INT >= 19) {
 				Intent intent = getCreationIntent();
 				startActivityForResult(intent, REQUEST_SAVE_ATTACHMENT);
 			} else {
-				viewModel.saveImage(attachment);
+				viewModel.saveImage(getVisibleAttachment());
 			}
 		};
 		Builder builder = new Builder(this, R.style.BriarDialogTheme);
@@ -303,7 +272,7 @@ public class ImageActivity extends BriarActivity
 		String fileName = sdf.format(new Date());
 		Intent intent = new Intent(ACTION_CREATE_DOCUMENT);
 		intent.addCategory(CATEGORY_OPENABLE);
-		intent.setType(attachment.getMimeType());
+		intent.setType(getVisibleAttachment().getMimeType());
 		intent.putExtra(EXTRA_TITLE, fileName);
 		return intent;
 	}
@@ -320,4 +289,26 @@ public class ImageActivity extends BriarActivity
 		viewModel.onSaveStateSeen();
 	}
 
+	AttachmentItem getVisibleAttachment() {
+		return attachments.get(viewPager.getCurrentItem());
+	}
+
+	private class ImagePagerAdapter extends FragmentStatePagerAdapter {
+
+		private ImagePagerAdapter(FragmentManager fm) {
+			super(fm);
+		}
+
+		@Override
+		public Fragment getItem(int position) {
+			return ImageFragment.newInstance(attachments.get(position));
+		}
+
+		@Override
+		public int getCount() {
+			return attachments.size();
+		}
+
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageFragment.java

@@ -0,0 +1,125 @@
+package org.briarproject.briar.android.conversation;
+
+import android.arch.lifecycle.ViewModelProvider;
+import android.arch.lifecycle.ViewModelProviders;
+import android.graphics.drawable.Animatable;
+import android.graphics.drawable.Drawable;
+import android.os.Bundle;
+import android.support.annotation.Nullable;
+import android.support.v4.app.Fragment;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+
+import com.bumptech.glide.load.DataSource;
+import com.bumptech.glide.load.engine.GlideException;
+import com.bumptech.glide.request.RequestListener;
+import com.bumptech.glide.request.target.Target;
+import com.github.chrisbanes.photoview.PhotoView;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.activity.BaseActivity;
+import org.briarproject.briar.android.conversation.glide.GlideApp;
+
+import javax.annotation.ParametersAreNonnullByDefault;
+import javax.inject.Inject;
+
+import static android.os.Build.VERSION.SDK_INT;
+import static android.widget.ImageView.ScaleType.FIT_START;
+import static com.bumptech.glide.load.engine.DiskCacheStrategy.NONE;
+import static org.briarproject.bramble.api.nullsafety.NullSafety.requireNonNull;
+import static org.briarproject.briar.android.conversation.ImageActivity.ATTACHMENT_POSITION;
+
+@MethodsNotNullByDefault
+@ParametersAreNonnullByDefault
+public class ImageFragment extends Fragment {
+
+	@Inject
+	ViewModelProvider.Factory viewModelFactory;
+
+	private AttachmentItem attachment;
+	private ImageViewModel viewModel;
+	private PhotoView photoView;
+
+	static ImageFragment newInstance(AttachmentItem a) {
+		ImageFragment f = new ImageFragment();
+		Bundle args = new Bundle();
+		args.putParcelable(ATTACHMENT_POSITION, a);
+		f.setArguments(args);
+		return f;
+	}
+
+	@Override
+	public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+		super.onActivityCreated(savedInstanceState);
+		BaseActivity a = (BaseActivity) requireNonNull(getActivity());
+		a.getActivityComponent().inject(this);
+	}
+
+	@Override
+	public void onCreate(@Nullable Bundle savedInstanceState) {
+		super.onCreate(savedInstanceState);
+
+		Bundle args = requireNonNull(getArguments());
+		attachment = requireNonNull(args.getParcelable(ATTACHMENT_POSITION));
+	}
+
+	@Nullable
+	@Override
+	public View onCreateView(LayoutInflater inflater,
+			@Nullable ViewGroup container,
+			@Nullable Bundle savedInstanceState) {
+		View v = inflater.inflate(R.layout.fragment_image, container,
+				false);
+
+		viewModel = ViewModelProviders.of(requireNonNull(getActivity()),
+				viewModelFactory).get(ImageViewModel.class);
+
+		photoView = v.findViewById(R.id.photoView);
+		photoView.setOnClickListener(view -> viewModel.clickPhoto());
+
+		// Request Listener
+		RequestListener<Drawable> listener = new RequestListener<Drawable>() {
+			@Override
+			public boolean onLoadFailed(@Nullable GlideException e,
+					Object model, Target<Drawable> target,
+					boolean isFirstResource) {
+				if (getActivity() != null)
+					getActivity().supportStartPostponedEnterTransition();
+				return false;
+			}
+
+			@Override
+			public boolean onResourceReady(Drawable resource, Object model,
+					Target<Drawable> target, DataSource dataSource,
+					boolean isFirstResource) {
+				if (SDK_INT >= 21 && !(resource instanceof Animatable)) {
+					// set transition name only when not animatable,
+					// because the animation won't start otherwise
+					photoView.setTransitionName(
+							attachment.getTransitionName());
+				}
+				// Move image to the top if overlapping toolbar
+				if (viewModel.isOverlappingToolbar(photoView, resource)) {
+					photoView.setScaleType(FIT_START);
+				}
+				if (getActivity() != null)
+					getActivity().supportStartPostponedEnterTransition();
+				return false;
+			}
+		};
+
+		// Load Image
+		GlideApp.with(this)
+				.load(attachment)
+				.diskCacheStrategy(NONE)
+				.error(R.drawable.ic_image_broken)
+				.dontTransform()
+				.addListener(listener)
+				.into(photoView);
+
+		return v;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ImageViewModel.java

@@ -4,9 +4,11 @@ import android.app.Application;
 import android.arch.lifecycle.AndroidViewModel;
 import android.arch.lifecycle.LiveData;
 import android.arch.lifecycle.MutableLiveData;
+import android.graphics.drawable.Drawable;
 import android.net.Uri;
 import android.support.annotation.Nullable;
 import android.support.annotation.UiThread;
+import android.view.View;
 
 import org.briarproject.bramble.api.db.DatabaseExecutor;
 import org.briarproject.bramble.api.db.DbException;
@@ -48,7 +50,9 @@ public class ImageViewModel extends AndroidViewModel {
 	@IoExecutor
 	private final Executor ioExecutor;
 
+	private final MutableLiveData<Boolean> imageClicked = new MutableLiveData<>();
 	private final MutableLiveData<Boolean> saveState = new MutableLiveData<>();
+	private int toolbarTop, toolbarBottom;
 
 	@Inject
 	ImageViewModel(Application application,
@@ -61,6 +65,45 @@ public class ImageViewModel extends AndroidViewModel {
 		this.ioExecutor = ioExecutor;
 	}
 
+	void clickPhoto() {
+		imageClicked.setValue(true);
+	}
+
+	/**
+	 * A LiveData that is true if the image was clicked,
+	 * false if it wasn't.
+	 *
+	 * Call {@link #onOnImageClickSeen()} after consuming an update.
+	 */
+	LiveData<Boolean> getOnImageClicked() {
+		return imageClicked;
+	}
+
+	@UiThread
+	void onOnImageClickSeen() {
+		imageClicked.setValue(false);
+	}
+
+	void setToolbarPosition(int top, int bottom) {
+		toolbarTop = top;
+		toolbarBottom = bottom;
+	}
+
+	boolean isOverlappingToolbar(View screenView, Drawable drawable) {
+		int width = drawable.getIntrinsicWidth();
+		int height = drawable.getIntrinsicHeight();
+		float widthPercentage = screenView.getWidth() / (float) width;
+		float heightPercentage = screenView.getHeight() / (float) height;
+		float scaleFactor = Math.min(widthPercentage, heightPercentage);
+		int realWidth = (int) (width * scaleFactor);
+		int realHeight = (int) (height * scaleFactor);
+		// return if photo doesn't use the full width,
+		// because it will be moved to the right otherwise
+		if (realWidth < screenView.getWidth()) return false;
+		int drawableTop = (screenView.getHeight() - realHeight) / 2;
+		return drawableTop < toolbarBottom && drawableTop != toolbarTop;
+	}
+
 	/**
 	 * A LiveData that is true if the image was saved,
 	 * false if there was an error and null otherwise.

briar-android/src/main/res/layout/activity_image.xml

@@ -8,12 +8,11 @@
 	android:background="@color/briar_black"
 	tools:context=".android.conversation.ImageActivity">
 
-	<com.github.chrisbanes.photoview.PhotoView
-		android:id="@+id/photoView"
+	<android.support.v4.view.ViewPager
+		android:id="@+id/viewPager"
 		android:layout_width="match_parent"
 		android:layout_height="match_parent"
-		tools:ignore="ContentDescription"
-		tools:srcCompat="@tools:sample/backgrounds/scenic"/>
+		tools:background="@color/briar_green_light"/>
 
 	<android.support.design.widget.AppBarLayout
 		android:id="@+id/appBarLayout"

briar-android/src/main/res/layout/fragment_image.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.github.chrisbanes.photoview.PhotoView
+	android:id="@+id/photoView"
+	xmlns:android="http://schemas.android.com/apk/res/android"
+	xmlns:tools="http://schemas.android.com/tools"
+	android:layout_width="match_parent"
+	android:layout_height="match_parent"
+	tools:ignore="ContentDescription"
+	tools:srcCompat="@tools:sample/backgrounds/scenic"/>