这是一个 d3 条形图。第 162 行，
.on("mouseover", console.log("I am on it"))
应该只在用户位于条形图上的条形上方时发生，但日志是在页面加载时输出的。
运行代码在这里，https://shanegibney.github.io/d3Mouseover/
完整代码在这里，https://github.com/shanegibney/d3Mouseover
<!DOCTYPE html>
<meta charset="utf-8">
<style type="text/css">
body {
font-family: avenir next, sans-serif;
font-size: 12px;
}
.zoom {
cursor: move;
fill: none;
pointer-events: all;
}
.axis {
stroke-width: 0.5px;
stroke: #888;
font: 10px avenir next, sans-serif;
}
.axis>path {
stroke: #888;
}
</style>
<body>
<div id="totalDistance">
</div>
</body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
/* Adapted from: https://bl.ocks.org/mbostock/34f08d5e11952a80609169b7917d4172 */
var margin = {
top: 20,
right: 20,
bottom: 90,
left: 50
},
margin2 = {
top: 230,
right: 20,
bottom: 30,
left: 50
},
width = 960 - margin.left - margin.right,
height = 300 - margin.top - margin.bottom,
height2 = 300 - margin2.top - margin2.bottom;
var parseTime = d3.timeParse("%Y-%m-%d %H:%M");
var x = d3.scaleTime().range([0, width]),
x2 = d3.scaleTime().range([0, width]),
y = d3.scaleLinear().range([height, 0]),
y2 = d3.scaleLinear().range([height2, 0]),
dur = d3.scaleLinear().range([0, 12]);
var xAxis = d3.axisBottom(x).tickSize(0),
xAxis2 = d3.axisBottom(x2).tickSize(0),
yAxis = d3.axisLeft(y).tickSize(0);
var brush = d3.brushX()
.extent([
[0, 0],
[width, height2]
])
.on("start brush end", brushed);
var zoom = d3.zoom()
.scaleExtent([1, Infinity])
.translateExtent([
[0, 0],
[width, height]
])
.extent([
[0, 0],
[width, height]
])
.on("zoom", zoomed);
var svg = d3.select("body").append("svg")
.attr("width", width + margin.left + margin.right)
.attr("height", height + margin.top + margin.bottom);
svg.append("defs").append("clipPath")
.attr("id", "clip")
.append("rect")
.attr("width", width)
.attr("height", height);
var focus = svg.append("g")
.attr("class", "focus")
.attr("transform", "translate(" + margin.left + "," + margin.top + ")");
var context = svg.append("g")
.attr("class", "context")
.attr("transform", "translate(" + margin2.left + "," + margin2.top + ")");
d3.json("dataDefault.json", function(error, data) {
if (error) throw error;
var parseTime = d3.timeParse("%Y-%m-%d %H:%M");
var mouseoverTime = d3.timeFormat("%a %e %b %Y %H:%M");
var minTime = d3.timeFormat("%b%e, %Y");
var parseDate = d3.timeParse("%b %Y");
data.forEach(function(d) {
d.mouseoverDisplay = parseTime(d.date);
d.date = parseTime(d.date);
d.end = parseTime(d.end);
d.duration = ((d.end - d.date) / (60 * 1000)); // session duration in minutes
d.distance = +d.distance;
d.intensityInverted = (1 / (d.distance / d.duration)); // inverse of intensity so that the light colour is for low intensity and dark colour is for high intensity
d.intensity = Math.round(d.distance / d.duration); // actually intensity, metres per minute.
d.course = d.course.toLowerCase();
return d;
},
function(error, data) {
if (error) throw error;
});
var total = 0;
data.forEach(function(d) {
total = d.distance + total;
});
var minDate = d3.min(data, function(d) {
return d.date;
});
total = String(total).replace(/(.)(?=(\d{3})+$)/g, '$1,') //place thousands comma in total distance string
var xMin = d3.min(data, function(d) {
return d.date;
});
var yMax = Math.max(20, d3.max(data, function(d) {
return d.distance;
}));
dur.domain([0, d3.max(data, function(d) {
return d.duration;
})]);
var colorScale = d3.scaleSequential(d3.interpolateInferno)
.domain([0, d3.max(data, function(d) {
return d.intensityInverted;
})]);
var totalDistance = d3.select("#totalDistance").append("p").text("Total distance: " + total + "m");
x.domain([xMin, new Date()]);
y.domain([0, yMax]);
x2.domain(x.domain());
y2.domain(y.domain());
// append scatter plot to main chart area
var messages = focus.append("g");
messages.attr("clip-path", "url(#clip)");
messages.selectAll("message")
.data(data)
.enter().append("rect")
.style("fill", function(d) {
return colorScale(d.intensityInverted);
})
.attr("class", "message")
.attr("x", function(d) {
return x(d.date);
})
.attr("y", function(d) {
return y(d.distance);
})
.attr("width", function(d) {
return dur(d.duration);
})
.attr("height", function(d) {
return height - y(d.distance);
})
// .on("mouseover", onit);
.on("mouseover", () => console.log("I am now on it for sure!"));
// function onit(d) {
// console.log("I am on it now!")
// }
focus.append("g")
.attr("class", "axis x-axis")
.attr("transform", "translate(0," + height + ")")
.call(xAxis);
focus.append("g")
.attr("class", "axis axis--y")
.call(yAxis);
// Summary Stats
focus.append("text")
.attr("transform", "rotate(-90)")
.attr("y", 0 - margin.left)
.attr("x", 0 - (height / 2))
.attr("dy", "1em")
.style("text-anchor", "middle")
.text("Distance in meters");
// focus.append("text")
// .attr("x", width - margin.right)
// .attr("dy", "1em")
// .attr("text-anchor", "end")
// // .text("Messages: " + num_messages(data, x));
// .text("Total distance: " + total + "m");
svg.append("text")
.attr("transform",
"translate(" + ((width + margin.right + margin.left) / 2) + " ," +
(height + margin.top + margin.bottom) + ")")
.style("text-anchor", "middle")
.text("Date");
svg.append("rect")
.attr("class", "zoom")
.attr("width", width)
.attr("height", height)
.attr("transform", "translate(" + margin.left + "," + margin.top + ")")
.call(zoom);
// append scatter plot to brush chart area
var messages = context.append("g");
messages.attr("clip-path", "url(#clip)");
messages.selectAll("message")
.data(data)
.enter().append("rect")
.style("fill", function(d) {
return colorScale(d.intensityInverted);
})
.attr("class", "message")
.attr("x", function(d) {
return x2(d.date);
})
.attr("y", function(d) {
return y2(d.distance);
})
.attr("width", function(d) {
return dur(d.duration);
})
.attr("height", function(d) {
return height2 - y2(d.distance);
});
context.append("g")
.attr("class", "axis x-axis")
.attr("transform", "translate(0," + height2 + ")")
.call(xAxis2);
context.append("g")
.attr("class", "brush")
.call(brush)
.call(brush.move, x.range());
});
//create brush function redraw scatterplot with selection
function brushed() {
if (d3.event.sourceEvent && d3.event.sourceEvent.type === "zoom") return; // ignore brush-by-zoom
var s = d3.event.selection || x2.range();
x.domain(s.map(x2.invert, x2));
focus.selectAll(".message")
.attr("x", function(d) {
return x(d.date);
})
.attr("y", function(d) {
return y(d.distance);
})
.attr("width", function(d) {
return dur(d.duration);
})
.attr("height", function(d) {
return height - y(d.distance);
});
focus.select(".x-axis").call(xAxis);
svg.select(".zoom").call(zoom.transform, d3.zoomIdentity
.scale(width / (s[1] - s[0]))
.translate(-s[0], 0));
var e = d3.event.selection;
var selectedMessages = focus.selectAll('.message').filter(function() {
var xValue = this.getAttribute('x');
return e[0] <= xValue && xValue <= e[1];
});
// console.log(selectedMessages.nodes().length);
}
function zoomed() {
if (d3.event.sourceEvent && d3.event.sourceEvent.type === "brush") return; // ignore zoom-by-brush
var t = d3.event.transform;
x.domain(t.rescaleX(x2).domain());
focus.selectAll(".message")
// .enter().append("rect")
// .style("fill", function(d) {
// return colorScale(d.intensityInverted);
// })
// .attr("class", "message")
.attr("x", function(d) {
return x(d.date);
})
.attr("y", function(d) {
return y(d.distance);
})
.attr("width", function(d) {
return dur(d.duration);
})
.attr("height", function(d) {
return height - y(d.distance);
});
focus.select(".x-axis").call(xAxis);
context.select(".brush").call(brush.move, x.range().map(t.invertX, t));
}
function handleMouseOver(d) {
d3.select(this)
.style("fill", "lightBlue");
g.select('text')
.attr("x", 15)
.attr("y", 5)
.text("Session no. " + d.number)
.append('tspan')
.text("Date: " + mouseoverTime(d.mouseoverDisplay))
.attr("x", 15)
.attr("y", 30)
.append('tspan')
.text("Distance: " + d.distance + "m")
.attr("x", 15)
.attr("y", 50)
.append('tspan')
.text("Duration: " + d.duration + " mins")
.attr("x", 15)
.attr("y", 70)
.append('tspan')
.text("Intensity: " + d.intensity + " meters/mins")
.attr("x", 15)
.attr("y", 90)
.append('tspan')
.text("Pool: " + d.pool + " (" + d.course + ")")
.attr("x", 15)
.attr("y", 110);
console.log("handleMouseOver function");
}
function handleMouseOut(d) {
d3.select(this)
.style("fill", function(d) {
return colorScale(d.intensityInverted);
});
g.select('text').text("Total distance since " + minTime(minDate) + ": " + total + "m");
}
</script>
示例数据，
[{
"number": "1",
"date": "2016-11-09 11:15",
"end": "2016-11-09 11:45",
"distance": "1100",
"course": "LC",
"pool": "UCD"
},
{
"number": "2",
"date": "2016-11-10 10:40",
"end": "2016-11-10 11:20",
"distance": "1500",
"course": "LC",
"pool": "UCD"
},
{
"number": "3",
"date": "2016-11-11 16:45",
"end": "2016-11-11 17:50",
"distance": "2000",
"course": "LC",
"pool": "UCD"
},
{
"number": "4",
"date": "2016-11-12 12:48",
"end": "2016-11-12 13:53",
"distance": "2500",
"course": "LC",
"pool": "UCD"
}
]
我在这里添加了最后两行，但还是不行，
var messages = focus.append("g");
messages.attr("clip-path", "url(#clip)");
messages.selectAll("message")
.data(data)
.enter().append("rect")
.style("fill", function(d) {
return colorScale(d.intensityInverted);
})
.attr("class", "message")
.attr("x", function(d) {
return x(d.date);
})
.attr("y", function(d) {
return y(d.distance);
})
.attr("width", function(d) {
return dur(d.duration);
})
.attr("height", function(d) {
return height - y(d.distance);
})
// .on("mouseover", onit);
.on("mouseover", () => console.log("I am now on it for sure!"));
// function onit(d) {
// console.log("I am on it now!")
// }
我怀疑问题是因为我正在使用 brushX() 和缩放。
最佳答案
当你这样做时:
.on("mouseover", console.log("I am on it"))
您正在将 console.log 函数的结果 传递给回调。相反，您想传递它的引用:
.on("mouseover", function(){
console.log("I am on it")
})
检查此代码段(不要将鼠标悬停在圆圈上!):
var circle = d3.select("circle");
circle.on("mouseover", console.log("I'm on it!"));<script src="https://d3js.org/d3.v4.min.js"></script>
<svg>
<circle cx="50" cy="50" r="15" fill="teal"></circle>
</svg>现在是相同的代码，引用 console.log:
var circle = d3.select("circle");
circle.on("mouseover", () => console.log("I'm on it!"));<script src="https://d3js.org/d3.v4.min.js"></script>
<svg>
<circle cx="50" cy="50" r="15" fill="teal"></circle>
</svg>关于javascript - d3.on ("mouseover") 在鼠标悬停之前发生，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/42420317/