React Native - 异常“-[NSNull 长度]：发送到实例 0x1e6c059b0”的无法识别的选择器在调用 multiSet 时被抛出

Question

我在应用程序加载后几秒钟收到此错误（但有时在几分钟或几次下载后并不总是如此）。我需要解决这个问题。
如果需要更多细节和/或编辑 - 请告诉我，我会制作它们。

异常“-[NSNull 长度]：发送到实例 0x1e6c059b0”的无法识别的选择器在使用参数调用目标 AsyncLocalStorage 上的 multiSet 时被抛出（（（“@Ye-Music:songs”，“”）），483）

带有 AsyncStorage 的功能：

allSongs = () => {
    console.log('hello function!');
    fetch(URL + "/SongsList", {
      body: null,  //// sending null because its a view from SQL db
      method: "POST",
      headers: {
        Accept: 'application/json',
        "Content-type": "application/json; charset=UTF-8"
      }
    })
      .then(res => { return res.json()})
      .then((songsResult) => {
        AsyncStorage.setItem("@Ye-Music:songs", songsResult.d);
      })
      .catch(err => {
        console.error(err);
      });
  };

包.json

"dependencies": {
    "@expo/samples": "2.1.1",
    "expo": "29.0.0",
    "react": "16.3.1",
    "react-native": "https://github.com/expo/react-native/archive/sdk-29.0.0.tar.gz",
    "react-native-elements": "^0.19.1",
    "react-native-material-cards": "^1.0.9",
    "react-native-music-control": "^0.7.3",
    "react-native-music-player-service": "^0.1.4-beta",
    "react-native-search-header": "^0.3.0",
    "react-native-sound": "^0.10.9",
    "react-native-track-player": "^0.2.5",
    "react-navigation": "^2.9.3"
},

Answer 1

确保songsResult.d不是未定义并且是长度> 0的字符串！