Enable media gallery fullscreen mode (#813)

* feat: Enable fullscreen mode on the media gallery screen

* Move `fitsSystemWindows` attribute to root view

* Rename for clarity

* Update fullscreen flag

* Set system bars behaviour for api >= 30

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

@@ -27,6 +27,8 @@ import android.os.Build;
 import android.os.Build.VERSION;
 import android.os.Build.VERSION_CODES;
 import android.os.Bundle;
+import android.os.Handler;
+import android.os.Looper;
 import android.view.GestureDetector;
 import android.view.LayoutInflater;
 import android.view.Menu;
@@ -36,6 +38,8 @@ import android.view.MotionEvent;
 import android.view.View;
 import android.view.ViewGroup;
 import android.view.Window;
+import android.view.WindowInsets;
+import android.view.WindowInsetsController;
 import android.widget.FrameLayout;
 import android.widget.TextView;
 import android.widget.Toast;
@@ -92,6 +96,8 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
 
   private final static String TAG = MediaPreviewActivity.class.getSimpleName();
 
+  private static final int UI_ANIMATION_DELAY     = 300;
+
   public static final String ADDRESS_EXTRA        = "address";
   public static final String DATE_EXTRA           = "date";
   public static final String SIZE_EXTRA           = "size";
@@ -99,6 +105,7 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
   public static final String OUTGOING_EXTRA       = "outgoing";
   public static final String LEFT_IS_RECENT_EXTRA = "left_is_recent";
 
+  private View                  rootContainer;
   private ViewPager             mediaPager;
   private View                  detailsContainer;
   private TextView              caption;
@@ -118,6 +125,26 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
 
   private int restartItem = -1;
 
+  private boolean isFullscreen = false;
+  private final Handler hideHandler = new Handler(Looper.myLooper());
+  private final Runnable showRunnable = () -> {
+    getSupportActionBar().show();
+  };
+  private final Runnable hideRunnable = () -> {
+    if (VERSION.SDK_INT >= 30) {
+      rootContainer.getWindowInsetsController().hide(WindowInsets.Type.statusBars() | WindowInsets.Type.navigationBars());
+      rootContainer.getWindowInsetsController().setSystemBarsBehavior(WindowInsetsController.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE);
+    } else {
+      rootContainer.setSystemUiVisibility(
+              View.SYSTEM_UI_FLAG_LOW_PROFILE |
+                      View.SYSTEM_UI_FLAG_FULLSCREEN |
+                      View.SYSTEM_UI_FLAG_LAYOUT_STABLE |
+                      View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY |
+                      View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION |
+                      View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
+    }
+  };
+
   public static Intent getPreviewIntent(Context context, Slide slide, MmsMessageRecord mms, Recipient threadRecipient) {
     Intent previewIntent = null;
     if (MediaPreviewActivity.isContentTypeSupported(slide.getContentType()) && slide.getUri() != null) {
@@ -147,6 +174,32 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
     initializeObservers();
   }
 
+  private void toggleFullscreen() {
+    if (isFullscreen) {
+      exitFullscreen();
+    } else {
+      enterFullscreen();
+    }
+  }
+
+  private void enterFullscreen() {
+    getSupportActionBar().hide();
+    isFullscreen = true;
+    hideHandler.removeCallbacks(showRunnable);
+    hideHandler.postDelayed(hideRunnable, UI_ANIMATION_DELAY);
+  }
+
+  private void exitFullscreen() {
+    if (Build.VERSION.SDK_INT >= 30) {
+      rootContainer.getWindowInsetsController().show(WindowInsets.Type.statusBars() | WindowInsets.Type.navigationBars());
+    } else {
+      rootContainer.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION);
+    }
+    isFullscreen = false;
+    hideHandler.removeCallbacks(hideRunnable);
+    hideHandler.postDelayed(showRunnable, UI_ANIMATION_DELAY);
+  }
+
   @Override
   public boolean dispatchTouchEvent(MotionEvent ev) {
     clickDetector.onTouchEvent(ev);
@@ -223,6 +276,7 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
   }
 
   private void initializeViews() {
+    rootContainer = findViewById(R.id.media_preview_root);
     mediaPager = findViewById(R.id.media_pager);
     mediaPager.setOffscreenPageLimit(1);
 
@@ -295,12 +349,13 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
       }
     });
 
-    clickDetector = new GestureDetector(new GestureDetector.SimpleOnGestureListener() {
+    clickDetector = new GestureDetector(this, new GestureDetector.SimpleOnGestureListener() {
       @Override
       public boolean onSingleTapUp(MotionEvent e) {
         if (e.getY() < detailsContainer.getTop()) {
           detailsContainer.setVisibility(detailsContainer.getVisibility() == View.VISIBLE ? View.GONE : View.VISIBLE);
         }
+        toggleFullscreen();
         return super.onSingleTapUp(e);
       }
     });

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

@@ -4,8 +4,10 @@
     xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:id="@+id/media_preview_root"
     android:layout_width="match_parent"
-    android:layout_height="match_parent">
+    android:layout_height="match_parent"
+    android:fitsSystemWindows="true">
 
     <com.google.android.material.appbar.AppBarLayout
         style="@style/Widget.Session.AppBarLayout"
@@ -24,7 +26,7 @@
         android:id="@+id/media_pager"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        android:clickable="true"/>
+        android:clickable="true" />
 
     <LinearLayout
         android:id="@+id/media_preview_details_container"