使用新线程并停止之前的线程

checkAndStopWorkingThread();

workingThread = new Thread() {
    public void run() {
      ......
    }

    ;
};
workingThread.start();

private void checkAndStopWorkingThread() {
    if (workingThread != null) {
        workingThread.stop();
        workingThread = null;
    }
}