Question

我正在尝试使用Qt框架从URL中提取JSON数据，并且我遇到了从get请求返回的一些问题。我已经看到有关我的问题的多个问题，但是没有一个给定的解决方案解决了我的问题。

所以我有一个按钮，一旦点击，就应该执行get请求。这是我的代码。

//When button is pressed
void Test1::onClickCapture()
{
    qDebug() << "Capture Clicked!!";
    toPopulate();
}

//Code to execute the connection
void Test1::toPopulate() {
    qDebug() << "Populating!";

    QNetworkAccessManager* manager = new QNetworkAccessManager(this);
    QNetworkRequest request;
    QUrl url("https://jsonplaceholder.typicode.com/posts/1");
    request.setUrl(url);
    QNetworkReply *reply = manager->get(request);
    connect(reply, &QNetworkReply::readyRead, this, &Test1::onResult);
}

//And finally, my onResult slot
void Test1::onResult() {
    reply->deleteLater();
    if (reply->error() != QNetworkReply::NoError) {
        return;
    }
    qDebug() << "Response!";
}

每次调试代码时，它都不会进入我的onResult插槽。

我也得到了这个错误，这可能是相关的。

QObject :: connect：无法连接（null）:: aboutToQuit（）到QNativeWifiEngine :: closeHandle（）

Answer 1

我修改了你的代码。它对我来说很好：

//Code to execute the connection
void MainWindow::toPopulate() {
    qDebug() << "Populating!";

    QNetworkAccessManager* manager = new QNetworkAccessManager(this);
    QNetworkRequest request;
    QUrl url("https://jsonplaceholder.typicode.com/posts/1");
    request.setUrl(url);
    QNetworkReply *reply = manager->get(request);
    connect(reply, SIGNAL(downloadProgress(qint64,qint64)), this, SLOT(downloading(qint64,qint64)));
    connect(reply, SIGNAL(finished()), this, SLOT(onResult()));
}

void MainWindow::downloading(qint64 bytesReceived, qint64 bytesTotal) {
    qDebug() << "Downloading " << bytesReceived/bytesTotal*100 << " %.";
}

//And finally, my onResult slot
void MainWindow::onResult() {
    QNetworkReply* reply = qobject_cast<QNetworkReply*> (QObject::sender());
    if (reply->error() != QNetworkReply::NoError) {
        qDebug() << "Error downloading. " << reply->errorString();
        return;
    }
    reply->deleteLater();
    qDebug() << "Response! " << reply->readAll();
}

结果：

Populating!
Downloading  -29200  %.
Downloading  100  %.
Response!  "{\n  \"userId\": 1,\n  \"id\": 1,\n  \"title\": \"sunt aut facere repellat provident occaecati excepturi optio reprehenderit\",\n  \"body\": \"quia et suscipit\\nsuscipit recusandae consequuntur expedita et cum\\nreprehenderit molestiae ut ut quas totam\\nnostrum rerum est autem sunt rem eveniet architecto\"\n}"

Qt网络访问管理器JSON获取响应

1 个答案: