public class FlashUtils {  private static FlashUtils utils;  private static Camera camera;  public static boolean mIsOpen = true;  //使用單例模式在這里初始化相機  public static FlashUtils getInstance() {    if (utils == null) {      utils = new FlashUtils();    }    try {      if (camera == null) {        camera = Camera.open();      }    } catch (Exception e) {      if (camera != null) {        camera.release();      }      camera = null;    }    return utils;  }  //參考二維碼工具的閃光燈  public void switchFlash() {    try {      Parameters parameters = camera.getParameters();      if (mIsOpen) {        if (parameters.getFlashMode().equals("torch")) {          return;        } else {          parameters.setFlashMode("torch");        }      } else {        if (parameters.getFlashMode().equals("off")) {          return;        } else {          parameters.setFlashMode("off");        }      }      camera.setParameters(parameters);    } catch (Exception e) {      finishFlashUtils();    }    mIsOpen = !mIsOpen;  }  //頁面銷毀的時候調用此方法  public void finishFlashUtils() {    if (camera != null) {      camera.stopPreview();      camera.release();    }    camera = null;  }}