Enable Android's context menus in network list.

After #4326 Android users could no longer long-touch to bring up the
context menu for channels in the network list. Now they can again.

client/components/ChannelWrapper.vue

@@ -82,15 +82,11 @@ export default {
 			this.$root.switchToChannel(this.channel);
 		},
 		openContextMenu(event) {
-			// events.buttons will be 0 when the event is caused by a long
-			// touch on Android.
-			if (event.buttons !== 0) {
-				eventbus.emit("contextmenu:channel", {
-					event: event,
-					channel: this.channel,
-					network: this.network,
-				});
-			}
+			eventbus.emit("contextmenu:channel", {
+				event: event,
+				channel: this.channel,
+				network: this.network,
+			});
 		},
 	},
 };

client/components/ContextMenu.vue

@@ -2,6 +2,7 @@
 	<div
 		v-if="isOpen"
 		id="context-menu-container"
+		:class="{passthrough}"
 		@click="containerClick"
 		@contextmenu.prevent="containerClick"
 		@keydown.exact.up.prevent="navigateMenu(-1)"
@@ -49,6 +50,7 @@ export default {
 	data() {
 		return {
 			isOpen: false,
+			passthrough: false,
 			previousActiveElement: null,
 			items: [],
 			activeItem: -1,
@@ -60,18 +62,35 @@ export default {
 	},
 	mounted() {
 		eventbus.on("escapekey", this.close);
+		eventbus.on("contextmenu:cancel", this.close);
 		eventbus.on("contextmenu:user", this.openUserContextMenu);
 		eventbus.on("contextmenu:channel", this.openChannelContextMenu);
 	},
 	destroyed() {
 		eventbus.off("escapekey", this.close);
+		eventbus.off("contextmenu:cancel", this.close);
 		eventbus.off("contextmenu:user", this.openUserContextMenu);
 		eventbus.off("contextmenu:channel", this.openChannelContextMenu);
 
 		this.close();
 	},
 	methods: {
+		enablePointerEvents() {
+			this.passthrough = false;
+			document.body.removeEventListener("pointerup", this.enablePointerEvents, {
+				passive: true,
+			});
+		},
 		openChannelContextMenu(data) {
+			if (data.event.type === "contextmenu") {
+				// Pass through all pointer events to allow the network list's
+				// dragging events to continue triggering.
+				this.passthrough = true;
+				document.body.addEventListener("pointerup", this.enablePointerEvents, {
+					passive: true,
+				});
+			}
+
 			const items = generateChannelContextMenu(this.$root, data.channel, data.network);
 			this.open(data.event, items);
 		},

client/components/NetworkList.vue

@@ -82,6 +82,7 @@
 				role="region"
 				aria-live="polite"
 				@touchstart="onDraggableTouchStart"
+				@touchmove="onDraggableTouchMove"
 				@touchend="onDraggableTouchEnd"
 				@touchcancel="onDraggableTouchEnd"
 			>
@@ -205,6 +206,8 @@ import JoinChannel from "./JoinChannel.vue";
 import socket from "../js/socket";
 import collapseNetwork from "../js/helpers/collapseNetwork";
 import isIgnoredKeybind from "../js/helpers/isIgnoredKeybind";
+import distance from "../js/helpers/distance";
+import eventbus from "../js/eventbus";
 
 export default {
 	name: "NetworkList",
@@ -325,16 +328,25 @@ export default {
 			);
 		},
 		onDraggableChoose(event) {
-			if (this.isTouchEvent(event.originalEvent)) {
+			const original = event.originalEvent;
+
+			if (this.isTouchEvent(original)) {
 				// onDrag is only triggered when the user actually moves the
 				// dragged object but onChoose is triggered as soon as the
 				// item is eligible for dragging. This gives us an opportunity
 				// to tell the user they've held the touch long enough.
 				event.item.classList.add("ui-sortable-dragging-touch-cue");
+
+				if (original instanceof TouchEvent && original.touches.length > 0) {
+					this.startDrag = [original.touches[0].clientX, original.touches[0].clientY];
+				} else if (original instanceof PointerEvent) {
+					this.startDrag = [original.clientX, original.clientY];
+				}
 			}
 		},
 		onDraggableUnchoose(event) {
 			event.item.classList.remove("ui-sortable-dragging-touch-cue");
+			this.startDrag = null;
 		},
 		onDraggableTouchStart() {
 			if (event.touches.length === 1) {
@@ -343,6 +355,18 @@ export default {
 				document.body.classList.add("force-no-select");
 			}
 		},
+		onDraggableTouchMove(event) {
+			if (this.startDrag && event.touches.length > 0) {
+				const touch = event.touches[0];
+				const currentPosition = [touch.clientX, touch.clientY];
+
+				if (distance(this.startDrag, currentPosition) > 10) {
+					// Context menu is shown on Android after long touch.
+					// Dismiss it now that we're sure the user is dragging.
+					eventbus.emit("contextmenu:cancel");
+				}
+			}
+		},
 		onDraggableTouchEnd(event) {
 			if (event.touches.length === 0) {
 				document.body.classList.remove("force-no-select");

client/css/style.css

@@ -2252,6 +2252,14 @@ part/quit messages where we don't load previews (adds a blank line otherwise) */
 	background: transparent;
 }
 
+#context-menu-container.passthrough {
+	pointer-events: none;
+}
+
+#context-menu-container.passthrough > * {
+	pointer-events: auto;
+}
+
 .mentions-popup,
 #context-menu,
 .textcomplete-menu {

client/js/helpers/distance.js

@@ -0,0 +1,5 @@
+function distance([x1, y1], [x2, y2]) {
+	return Math.hypot(x1 - x2, y1 - y2);
+}
+
+export default distance;

client/js/helpers/listenForTwoFingerSwipes.js

@@ -1,5 +1,7 @@
 "use strict";
 
+import distance from "./distance";
+
 // onTwoFingerSwipe will be called with a cardinal direction ("n", "e", "s" or
 // "w") as its only argument.
 function listenForTwoFingerSwipes(onTwoFingerSwipe) {
@@ -89,10 +91,6 @@ function getSwipe(hist) {
 	return getCardinalDirection(hist[0].center, hist[hist.length - 1].center);
 }
 
-function distance([x1, y1], [x2, y2]) {
-	return Math.hypot(x1 - x2, y1 - y2);
-}
-
 function getCardinalDirection([x1, y1], [x2, y2]) {
 	// If θ is the angle of the vector then this is tan(θ)
 	const tangent = (y2 - y1) / (x2 - x1);