I hve overided Opportunity New Standedbutton with below VF page to prepopulate some values up on creating new record 
it is working fine for desk top but in salesforce1 not working please help me below is my code

<apex:page action="{!prepopulateValues}" standardController="Opportunity" extensions="MyControlleroppy">
</apex:page>
 
 public class MyControlleroppy
{

public opportunity oppty {get;set;}  

      
    private final Opportunity o; //Opportunity object
    
    //constructor
    public MyControlleroppy(ApexPages.StandardController standardPageController) {
        o = (Opportunity)standardPageController.getRecord(); 
    }
    
    //method called from the Visualforce page action attribute
    public PageReference prepopulateValues() {
        
        Map<String, String> passedParams = System.currentPageReference().getParameters(); 
        PageReference pageWhereWeEndUp = new PageReference('/006/e');
        
        pageWhereWeEndUp.getParameters().putAll(passedParams); 
        
        
            
        pageWhereWeEndUp.getParameters().put('opp3','Prospecting'); 
        pageWhereWeEndUp.getParameters().put('opp9',Date.Today().addDays(30).format()); 
        
        String dropSaveNew = pageWhereWeEndUp.getParameters().remove('save_new'); 
        String dropSave = pageWhereWeEndUp.getParameters().remove('save'); 
        
        pageWhereWeEndUp.getParameters().put('nooverride', '1'); 
        pageWhereWeEndUp.setRedirect(true);
        return pageWhereWeEndUp;
    }

}