如何自定义Google Geo Chart中的工具提示文本

Question

I need remove first empty string in tooltip. I'm used formater, for change first string to '', but I'm can't remove it. If I change '' to null then in first string shows first column data.

Code:

var data = new google.visualization.DataTable();
data.addColumn('string', 'State');
data.addColumn('number', 'TempNumber');
data.addColumn({
    type: 'string',
    role: 'tooltip'
});
data.addRows([
    ['Ohio', 0, 'Ohio'],
    ...
]);
var options = {
    width:      580,
    region:     'US',
    resolution: 'provinces',
    colorAxis:  {colors: ['#abb7df']},
    legend:     'none'
};
var chart = new google.visualization.GeoChart(document.getElementById('chart_div'));
var formatter = new google.visualization.PatternFormat('');
    formatter.format(data, [0,1,2]);

chart.draw(data, options);

Answer 1

Unfortunately there is no easy way to currently do this (without drawing your own tooltip function to draw the boxes). In the future, hopefully they will implement isHtml: true to geocharts, but right now it isn't supported.

Tooltip cannot do what you want it to do in its current implementation. You can reduce text size, but that will also reduce the size of the text you want shown. You can change color, but again it affects the entire tooltip. There isn't really much you can do to fix the issue rather than implement your own form of tooltipping (creating a function that will take the column 0 value of whatever your mouse is over, and display it either in a separate in the page, or have it calculate where your mouse is and show it there).