[英]Possible Unhandled Promise Rejection - React-Native with Firebase
我正在嘗試使用 React-Native 應用程序對新的 Firebase 實例進行 fetch API 調用,但我遇到了以下錯誤:
Possible Unhandled Promise Rejection (id: 0):
Network request failed
TypeError: Network request failed
at XMLHttpRequest.xhr.onerror (http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:25119:8)
at XMLHttpRequest.dispatchEvent (http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:10405:15)
at XMLHttpRequest.setReadyState (http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:26688:6)
at XMLHttpRequest.__didCompleteResponse (http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:26536:6)
at http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:26630:52
at RCTDeviceEventEmitter.emit (http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:9638:23)
at MessageQueue.__callFunction (http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:7493:34)
at http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:7375:8
at guard (http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:7306:1)
at MessageQueue.callFunctionReturnFlushedQueue (http://localhost:8081/index.ios.bundle?platform=ios&dev=true&minify=false:7374:1)
函數看起來像這樣:
getNotes(username){
username = username.toLowerCase().trim();
var url = `https://myproject-6342.firebaseio.com/${username}.json`;
return fetch(url).then((res) => res.json());
},
addNote(username, note){
username = username.toLowerCase().trim();
var url = `https://myproject-6342.firebaseio.com/${username}.json`;
return fetch(url, {
method: 'post',
body: JSON.stringify(note)
}).then((res) => res.json());
}
這里出了什么問題?
當發生網絡錯誤時,來自 fetch API 的承諾會以TypeError拒絕,這意味着您必須處理錯誤。 例子:
function _handleError(errorMessage) {
console.log(errorMessage);
}
fetch('https://api.github.com/users/octocat/repos').then(function(response) {
if(response.ok) {
return response.json();
} else {
_handleError(`Oops, something went wrong: ${response.status}, ${response.statusText}`);
}
}).then(function(data) {
if(data) {
console.log('success', data);
}
}).catch(function(error) {
_handleError(`There has been a problem with your fetch operation: ${error.message}`);
});
更多信息: https : //developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch#Checking_that_the_fetch_was_successful
好吧,在我的情況下,模擬器互聯網無法正常工作,我按照以下線程進行操作。 Android模擬器無法訪問互聯網
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