ExtJS setting a textareafield setValue()

Question

Im learning Extjs and have a problem , when i try to append new text to an item i get an error same goes for getValue . getValue 相同。 When i try setVisible it works like it should be.

Ext.Loader.setConfig({enabled:true});

Ext.application({
    name: 'app',
    controllers:[
  ],
    appFolder: 'app',
    launch: function() {
        var panel = new Ext.form.FormPanel({
          renderTo:Ext.getBody(),
          title:'Panel',
          width:400,
          bodyPadding: 10,
          autoHeight:true,
          items:[{
            xtype:'textareafield',
            name: 'textInput',
            id:'textId',
            value:'why not'
          },{
            xtype:'button',
            text:'Helllo',
            handler:function(){
              console.log('button click')
              var tf = Ext.get('textId');
                    tf.setValue('This should change!')
            }
          }],
        });
    }
});

Thanks

Answer 1

That's because Ext.get() will return an Ext.Element .

What you want to use is Ext.getCmp('textId') which will return the component.

The Element is basically the Ext wrapper round the Dom element, so it has methods like setVisible, but you want to get the text area component, which has all the methods you're after.