android不重复弹出的Toast

public class ToastUtil {
    private static WeakReference<Toast> sToast;

    public static void show(CharSequence content) {
        if (TextUtils.isEmpty(content)) {
            return;
        }
        if (sToast != null && sToast.get() != null) {
            sToast.get().setText(content);
            sToast.get().show();
        } else {
            Toast toast = Toast.makeText(MyApplication.getApp(), content, Toast.LENGTH_SHORT);
            sToast = new WeakReference<>(toast);
            toast.show();
        }
    }

    public static void cancel() {
        if (sToast != null && sToast.get() != null) {
            sToast.get().cancel();
        }
    }
}