How to add Undo & Redo on Blockly Workspace

[shinu sam]

Hello,

     This forum helps me to solve problems of my project related to blockly.  I am thankful to all members who are actively participating in this forum. Today I am trying to add Undo, Redo, Repeat properties in Blockly Workspace. But i am not able to create it. If anyone know please reply me.  Also i would like to know that  how to create  repeltion on blockly blocks. Kindly waiting for your valuable replies. 

Thank You.

[Neil Fraser]

Calling this will undo one step:

  Blockly.mainWorkspace.undo(false);

Calling this will redo one step:

  Blockly.mainWorkspace.undo(true);

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Neil Fraser
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[shinu sam]

Thank You Sir,

  

                        Unfortunately this code is not working.

<script>

var workspace = Blockly.inject('blocklyDiv',

{ toolbox: document.getElementById('toolbox')/*,allowUndoRedo: true*/ });

var defaultBlocks = document.getElementById('blocklyDefault');

Blockly.Xml.domToWorkspace(defaultBlocks, workspace);

Blockly.mainWorkspace.undo(true);

Blockly.mainWorkspace.undo(false);

</script>

 Please sugggest a solution for this  Sir. Kindly waiting for reply.

[Anschke]

Hi sinu sam,

I am not one of the Blockly professionals, but I give it a try to answer your question.
To make it work you gotta bind the two functions Neil suggested to e.g. Buttons - just calling them once on an empty workspace will of course have no effect.

Just put them into js functions like

function undoAction(){

Blockly.mainWorkspace.undo(false);

}

function redoAction(){

Blockly.mainWorkspace.undo(true);
}

and then bind these to the onclick-call of e.g. two Buttons defined in your .html file or application. When clicking them the main workspace will now perform the undo/redo actions.

I have to admit that these are somehow misleading as they more look like setters than function calls if one is not that familiar with blockly. 

Hope this answer helps to solve your problem!