Android : how to use bluetooth read String [duplicate]

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• How do I compare strings in Java? 24 answers

I modify android bluetooth chat sample source code , then I want to read Sting like "BT1051", so I modify source code :MainActivity.java

private final Handler mHandler = new Handler(){
  public void handleMessage(Message msg){
         switch(msg.what){
           case MESSAGE_READ:
           byte[] readBuf = (byte[]) msg.obj;
           String readMessage = new String(readBuf, 0, msg.arg1);
           if(readMessage=="BT1051"){
               digitalInBtn.setChecked(false);
           }else
               digitalInBtn.setChecked(true);
           }
           break; 
  }

}

and my digitalInBtn is ToggleButton . It's not working?somebody help?