为什么我没有得到带有此代码的ExtJs消息框？

Question

Ext.application({ 
    name: 'HelloExt', 
    launch: function() { 
        Ext.MessageBox.alert('title', 'msg', Ext.emptyFn); 
    } 
});

Answer 1

Is there any error message? My first guess would be that you're using dynamic loading and you haven't loaded the MessageBox before using it:

Ext.application({
    name: 'HelloExt',
    requires: ['Ext.window.MessageBox'],
    launch: function() {
        Ext.MessageBox.alert('title', 'msg', Ext.emptyFn);
    }
});