java - How to return an alert dialog -

i wanted know how can return alert dialog. have created alert dialog , appear in circumstances. should put in return?

for example

if(condition) return " alert dialog " 

how this?

will code you?

 return new alertdialog.builder(this) .settitle("delete entry") .setmessage("are sure want delete entry?") .setpositivebutton("yes", new dialoginterface.onclicklistener() {     public void onclick(dialoginterface dialog, int which) {          // continue delete     }  }) .setnegativebutton("no", new dialoginterface.onclicklistener() {     public void onclick(dialoginterface dialog, int which) {          // nothing     }  }); 

how display alert dialog on android?