一个关于Android编成问题

代码如下:

public class get extends MainActivity {
Socket socket;
BufferedReader in;
private EditText OP;
EditText dose=(EditText)findViewById(R.id.editText);
public get() {
try {
Socket socket = new Socket("192.168.11.254", 8080);
BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
new gd().start();
} catch (IOException e) {
e.printStackTrace();
}
}
class gd extends Thread {
    public void run() {
        while (this.isAlive()) {
            try {
                String kk = in.readLine();
                int k = (kk.lastIndexOf("dose"));
                String z;
                z = kk.substring(k + 5, k + 10);
                Thread.sleep(50);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }

    }

}
}

提示如下:

Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.view.View android.view.Window.findViewById(int)' on a null object reference

如何解决?