html5 - Mouse movement, while mouse down not working in Dart? -

html5 - Mouse movement, while mouse down not working in Dart? -

how mouse movements when you're have clicked.

i know how track whether or not mouse clicked:

canvas.onmousedown

and how track mouse motion canvas.onmousemove

so tried doing this:

//when mouse clicked canvas.onmousedown.listen((ondata){ print("mouse down!" + "(" + ondata.client.x.tostring() + ", " + ondata.client.y.tostring() + ")"); //check it's beingness dragged canvas.onmousemove.listen((ondata){ mousemovementsdown(ondata.client.x, ondata.client.y); }); });

but problem doesn't stop 1 time stop clicking. want track motion long mouse downwards , 1 time mouse no longer down, want stop tracking mouse's movement. can help me? reason thing continues reporting canvas.onmousemove after i've set mouse up.

i tried this:

if(canvas.onmousedown.listen(ondata) == true)

but apparently that's not how things work in dart >.>;

i read more streams on dart api docs, can explain me how close used? think said that's how stop getting input mouse event, how done don't understand how code written stop canvas.onmousemove.listen stream when canvas.onmouseup happens.

you can store reference mousemove streamsubscription , cancel on mouseup:

class="lang-dart prettyprint-override">canvas.onmousedown.listen((ondata) { streamsubscription mousemovestream = canvas.onmousemove.listen((ondata) { // things... }); canvas.onmouseup.listen((ondata) => mousemovestream.cancel()); });

html5 canvas html5-canvas dart dart-editor