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Preserve scroll offset when switching rooms

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When we change rooms, save the scroll offset, and restore the scroll when we
switch back.

Hopefully this fixes https://github.com/vector-im/vector-web/issues/80.
This commit is contained in:
Richard van der Hoff 2015-12-10 16:26:36 +00:00
parent 072130466c
commit 00656fc1dc
2 changed files with 140 additions and 31 deletions
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81
src/components/structures/MatrixChat.js
View file

@ -80,6 +80,9 @@ module.exports = React.createClass({
this.startMatrixClient();
}
this.focusComposer = false;
// scrollStateMap is a map from room id to the scroll state returned by
// RoomView.getScrollState()
this.scrollStateMap = {};
document.addEventListener("keydown", this.onKeyDown);
window.addEventListener("focus", this.onFocus);
if (this.state.logged_in) {
@ -202,27 +205,7 @@ module.exports = React.createClass({
break;
case 'view_room':
this.focusComposer = true;
var newState = {
currentRoom: payload.room_id,
page_type: this.PageTypes.RoomView,
};
if (this.sdkReady) {
// if the SDK is not ready yet, remember what room
// we're supposed to be on but don't notify about
// the new screen yet (we won't be showing it yet)
// The normal case where this happens is navigating
// to the room in the URL bar on page load.
var presentedId = payload.room_id;
var room = MatrixClientPeg.get().getRoom(payload.room_id);
if (room) {
var theAlias = MatrixTools.getCanonicalAliasForRoom(room);
if (theAlias) presentedId = theAlias;
}
this.notifyNewScreen('room/'+presentedId);
newState.ready = true;
}
this.setState(newState);
this._viewRoom(payload.room_id);
break;
case 'view_prev_room':
roomIndexDelta = -1;
@ -239,11 +222,7 @@ module.exports = React.createClass({
}
roomIndex = (roomIndex + roomIndexDelta) % allRooms.length;
if (roomIndex < 0) roomIndex = allRooms.length - 1;
this.focusComposer = true;
this.setState({
currentRoom: allRooms[roomIndex].roomId
});
this.notifyNewScreen('room/'+allRooms[roomIndex].roomId);
this._viewRoom(allRooms[roomIndex].roomId);
break;
case 'view_indexed_room':
var allRooms = RoomListSorter.mostRecentActivityFirst(
@ -251,11 +230,7 @@ module.exports = React.createClass({
);
var roomIndex = payload.roomIndex;
if (allRooms[roomIndex]) {
this.focusComposer = true;
this.setState({
currentRoom: allRooms[roomIndex].roomId
});
this.notifyNewScreen('room/'+allRooms[roomIndex].roomId);
this._viewRoom(allRooms[roomIndex].roomId);
}
break;
case 'view_room_alias':
@ -322,6 +297,49 @@ module.exports = React.createClass({
}
},
_viewRoom: function(roomId) {
// before we switch room, record the scroll state of the current room
this._updateScrollMap();
this.focusComposer = true;
var newState = {
currentRoom: roomId,
page_type: this.PageTypes.RoomView,
};
if (this.sdkReady) {
// if the SDK is not ready yet, remember what room
// we're supposed to be on but don't notify about
// the new screen yet (we won't be showing it yet)
// The normal case where this happens is navigating
// to the room in the URL bar on page load.
var presentedId = roomId;
var room = MatrixClientPeg.get().getRoom(roomId);
if (room) {
var theAlias = MatrixTools.getCanonicalAliasForRoom(room);
if (theAlias) presentedId = theAlias;
}
this.notifyNewScreen('room/'+presentedId);
newState.ready = true;
}
this.setState(newState);
if (this.scrollStateMap[roomId]) {
var scrollState = this.scrollStateMap[roomId];
this.refs.roomview.restoreScrollState(scrollState);
}
},
// update scrollStateMap according to the current scroll state of the
// room view.
_updateScrollMap: function() {
if (!this.refs.roomview) {
return;
}
var roomview = this.refs.roomview;
var state = roomview.getScrollState();
this.scrollStateMap[roomview.props.roomId] = state;
},
onLoggedIn: function(credentials) {
console.log("onLoggedIn => %s", credentials.userId);
MatrixClientPeg.replaceUsingAccessToken(
@ -590,6 +608,7 @@ module.exports = React.createClass({
case this.PageTypes.RoomView:
page_element = (
<RoomView
ref="roomview"
roomId={this.state.currentRoom}
key={this.state.currentRoom}
ConferenceHandler={this.props.ConferenceHandler} />

90
src/components/structures/RoomView.js
View file

@ -803,6 +803,96 @@ module.exports = React.createClass({
scrollNode.scrollTop = scrollNode.scrollHeight;
},
// scroll the event view to put the given event at the bottom.
//
// pixel_offset gives the number of pixels between the bottom of the event
// and the bottom of the container.
scrollToEvent: function(event_id, pixel_offset) {
var scrollNode = this._getScrollNode();
if (!scrollNode) return;
var messageWrapper = this.refs.messagePanel;
if (messageWrapper === undefined) return;
var idx = this._indexForEventId(event_id);
if (idx === null) {
// we don't seem to have this event in our timeline. Presumably
// it's fallen out of scrollback. We ought to backfill until we
// find it, but we'd have to be careful we didn't backfill forever
// looking for a non-existent event.
//
// for now, just scroll to the top of the buffer.
console.log("Refusing to scroll to unknown event "+event_id);
scrollNode.scrollTop = 0;
return;
}
// we might need to roll back the messagecap (to generate tiles for
// older messages). Don't roll it back past the timeline we have, though.
var minCap = this.state.room.timeline.length - Math.min(idx - INITIAL_SIZE, 0);
if (minCap > this.state.messageCap) {
this.setState({messageCap: minCap});
}
var node = this.eventNodes[event_id];
if (node === null) {
// getEventTiles should have sorted this out when we set the
// messageCap, so this is weird.
console.error("No node for event, even after rolling back messageCap");
return;
}
var wrapperRect = ReactDOM.findDOMNode(messageWrapper).getBoundingClientRect();
var boundingRect = node.getBoundingClientRect();
scrollNode.scrollTop += boundingRect.bottom + pixel_offset - wrapperRect.bottom;
},
// get the current scroll position of the room, so that it can be
// restored when we switch back to it
getScrollState: function() {
// we don't save the absolute scroll offset, because that
// would be affected by window width, zoom level, amount of scrollback,
// etc.
//
// instead we save the id of the last fully-visible event, and the
// number of pixels the window was scrolled below it - which will
// hopefully be near enough.
//
if (this.eventNodes === undefined) return null;
var messageWrapper = this.refs.messagePanel;
if (messageWrapper === undefined) return null;
var wrapperRect = ReactDOM.findDOMNode(messageWrapper).getBoundingClientRect();
for (var i = this.state.room.timeline.length-1; i >= 0; --i) {
var ev = this.state.room.timeline[i];
var node = this.eventNodes[ev.getId()];
if (!node) continue;
var boundingRect = node.getBoundingClientRect();
if (boundingRect.bottom < wrapperRect.bottom) {
return {
atBottom: this.atBottom,
lastDisplayedEvent: ev.getId(),
pixelOffset: wrapperRect.bottom - boundingRect.bottom,
}
}
}
// apparently the entire timeline is below the viewport. Give up.
return null;
},
restoreScrollState: function(scrollState) {
if(scrollState.atBottom) {
// we were at the bottom before. Ideally we'd scroll to the
// 'read-up-to' mark here.
} else if (scrollState.lastDisplayed) {
this.scrollToEvent(scrollState.lastDisplayedEvent,
scrollState.pixelOffset);
}
},
render: function() {
var RoomHeader = sdk.getComponent('rooms.RoomHeader');
var MessageComposer = sdk.getComponent('rooms.MessageComposer');