如何自動識別字母

char[] tt=text.toCharArray();
    boolean workable=true;
    for(int i=0;i<tt.length;i++){
     if( Character.isLowerCase(tt[i])){
      Log.v("","____okkkkk_"+tt[i]);
      workable=false;
      break;
     }
    }
       if(workable)
        work();
   }  
 
 public void work(){
  ExecutorService singleThreadExecutor=Executors.newSingleThreadExecutor();
  singleThreadExecutor.execute(new Runnable(){
   @Override
   public void run(){
    try{
     Log.v("","___::::"+(++num));
     Thread.sleep(2000);
     }catch(InterruptedException e){
    }
   }
 });
 }