Fix hold-to-speak and prompt text on mobile

src/room/PTTButton.tsx

@@ -43,23 +43,50 @@ export const PTTButton: React.FC<Props> = ({
   stopTalking,
 }) => {
   const [isHeld, setHeld] = useState(false);
-  const onDocumentMouseUp = useCallback(() => {
-    if (isHeld) stopTalking();
-    setHeld(false);
-  }, [isHeld, setHeld, stopTalking]);
+  const onWindowMouseUp = useCallback(
+    (e) => {
+      if (isHeld) stopTalking();
+      setHeld(false);
+    },
+    [isHeld, setHeld, stopTalking]
+  );
 
-  const onButtonMouseDown = useCallback(() => {
-    setHeld(true);
-    startTalking();
-  }, [setHeld, startTalking]);
+  const onWindowTouchEnd = useCallback(
+    (e: TouchEvent) => {
+      e.preventDefault();
+      if (isHeld) stopTalking();
+      setHeld(false);
+    },
+    [isHeld, setHeld, stopTalking]
+  );
+
+  const onButtonMouseDown = useCallback(
+    (e: React.MouseEvent<HTMLButtonElement>) => {
+      e.preventDefault();
+      setHeld(true);
+      startTalking();
+    },
+    [setHeld, startTalking]
+  );
+
+  const onButtonTouchStart = useCallback(
+    (e: React.TouchEvent<HTMLButtonElement>) => {
+      e.preventDefault();
+      setHeld(true);
+      startTalking();
+    },
+    [setHeld, startTalking]
+  );
 
   useEffect(() => {
-    window.addEventListener("mouseup", onDocumentMouseUp);
+    window.addEventListener("mouseup", onWindowMouseUp);
+    window.addEventListener("touchend", onWindowTouchEnd);
 
     return () => {
-      window.removeEventListener("mouseup", onDocumentMouseUp);
+      window.removeEventListener("mouseup", onWindowMouseUp);
+      window.removeEventListener("touchend", onWindowTouchEnd);
     };
-  }, [onDocumentMouseUp]);
+  }, [onWindowMouseUp, onWindowTouchEnd]);
   return (
     <button
       className={classNames(styles.pttButton, {
@@ -67,6 +94,7 @@ export const PTTButton: React.FC<Props> = ({
         [styles.error]: showTalkOverError,
       })}
       onMouseDown={onButtonMouseDown}
+      onTouchStart={onButtonTouchStart}
     >
       {activeSpeakerIsLocalUser || !activeSpeakerUserId ? (
         <MicIcon

src/room/PTTCallView.module.css

@@ -10,6 +10,12 @@
   width: 100%;
 }
 
+@media (hover: none) {
+  .pttCallView {
+    user-select: none;
+  }
+}
+
 .center {
   width: 100%;
   display: flex;

src/room/PTTCallView.tsx

@@ -38,6 +38,43 @@ import { ReactComponent as AudioIcon } from "../icons/Audio.svg";
 import { usePTTSounds } from "../sound/usePttSounds";
 import { PTTClips } from "../sound/PTTClips";
 
+function getPromptText(
+  showTalkOverError: boolean,
+  pttButtonHeld: boolean,
+  activeSpeakerIsLocalUser: boolean,
+  talkOverEnabled: boolean,
+  activeSpeakerUserId: string,
+  activeSpeakerDisplayName: string
+): string {
+  const isTouchScreen = Boolean(window.ontouchstart !== undefined);
+
+  if (showTalkOverError) {
+    return "You can't talk at the same time";
+  }
+
+  if (pttButtonHeld && activeSpeakerIsLocalUser) {
+    if (isTouchScreen) {
+      return "Release to stop";
+    } else {
+      return "Release spacebar key to stop";
+    }
+  }
+
+  if (talkOverEnabled && activeSpeakerUserId && !activeSpeakerIsLocalUser) {
+    if (isTouchScreen) {
+      return `Press and hold to talk over ${activeSpeakerDisplayName}`;
+    } else {
+      return `Press and hold spacebar to talk over ${activeSpeakerDisplayName}`;
+    }
+  }
+
+  if (isTouchScreen) {
+    return "Press and hold to talk";
+  } else {
+    return "Press and hold spacebar to talk";
+  }
+}
+
 interface Props {
   client: MatrixClient;
   roomId: string;
@@ -163,15 +200,14 @@ export const PTTCallView: React.FC<Props> = ({
             stopTalking={stopTalking}
           />
           <p className={styles.actionTip}>
-            {showTalkOverError
-              ? "You can't talk at the same time"
-              : pttButtonHeld && activeSpeakerIsLocalUser
-              ? "Release spacebar key to stop"
-              : talkOverEnabled &&
-                activeSpeakerUserId &&
-                !activeSpeakerIsLocalUser
-              ? `Press and hold spacebar to talk over ${activeSpeakerDisplayName}`
-              : "Press and hold spacebar to talk"}
+            {getPromptText(
+              showTalkOverError,
+              pttButtonHeld,
+              activeSpeakerIsLocalUser,
+              talkOverEnabled,
+              activeSpeakerUserId,
+              activeSpeakerDisplayName
+            )}
           </p>
           {userMediaFeeds.map((callFeed) => (
             <PTTFeed