1、优化getControllerString，适配TextEditingController为null

lib/utils/string_util.dart

@@ -49,8 +49,8 @@ String? getNowTime() {
 }
 
 //获取输入框内的信息
-String getControllerString(TextEditingController controller) {
-  return controller.value.text.toString().trim();
+String getControllerString(TextEditingController? controller) {
+  return controller?.value.text.toString().trim() ?? "";
 }
 
 //获取输入框内的文字长度