FieldImage opt_onClick initialisation when the block is defined in json

[retd-jerome]

Problem statement

Missing APIs in the JSON definitions.

There is no possibility to define a FieldImage opt_onClick via JSON (cf https://github.com/google/blockly/blob/master/core/field_image.js#L73)

More, as the FieldImage has no name attribute, you can't call "this.getField(name)" in an extension to define it.

Expected Behavior

Possibility to define the opt_onclick via JSON like

Blockly.Blocks['test_json'] = {
   init: function() {
     this.jsonInit({
        "type": "test_json",
        "message0": "json %1",
        "args0": [
           {
              "type": "field_image",
              "src": "https://www.gstatic.com/codesite/ph/images/star_on.gif",
              "width": 15,
              "height": 15,
              "alt": "*",
              **"onclick": "myFunction"**
           }
       ],
       "colour": 230,
       "tooltip": "",
       "helpUrl": ""
     });
   }
};

Actual Behavior

You can only define it via javascript

Blockly.Blocks['test_js'] = {
    init: function () {
        this.appendDummyInput()
            .appendField("js")
            .appendField(new Blockly.FieldImage("https://www.gstatic.com/codesite/ph/images/star_on.gif", 15, 15, "*", myFunction));
        this.setColour(230);
        this.setTooltip("");
        this.setHelpUrl("");
    }
};

function myFunction(e) {
    alert("Clicked");
    return 0;
};

Additional Information

I post this issue because of my initial message on the Blockly Google group (cf https://groups.google.com/forum/#!topic/blockly/rzcpN8iIrRU)

Thanks,
Best regards,
Jerome.

[RoboErikG]

Note that for the click callback since we don't know where the callback is defined when we load the JSON it'll need to be added somehow.

I'm not sure if this should require an extension to add the onclick function or use a registration method like registerButtonCallback() in the toolbox.

Adding the name attribute to the field_image should be a lot more straightforward and can be done separately in a small PR.

[RoboErikG]

Oops, Andrew pointed out to me the 'name' field gets used in block.js, not in the field, so adding a name should already work.

[retd-jerome]

Hi,

It fix my issue. I didn't realize I could give a name to the FieldImage type.
Thank you :)