我有一个项目是在 Ubuntu 14.04 LTS 上制作的,但是后来,我想测试 Raspberry Pi 是否能够运行我的这个小程序。 然后我按照这个 link 上的说明进行操作在 Pi 上本地编译和构建 qt5。
我成功地安装了 qt5,我什至可以编译和运行位于 qt 示例中的“cube”程序。
之后,我编译并安装了项目所需的 qtmultimedia 子模块。
好的,一切看起来都不错。然后我在 Pi 上克隆了我的项目,运行 qmake,然后运行 make。直到...我收到此错误消息:
In file included from ../mainWindow.h:14:0,
from ../main.cpp:3:
../core/core.h: In constructor ‘bumbatv::core::Core::Core()’:
../core/core.h:37:36: error: conversion from ‘int’ to ‘QString’ is ambiguous
../core/core.h:37:36: note: candidates are:
/usr/local/qt5/include/QtCore/qstring.h:649:31: note: QString::QString(const char*)
/usr/local/qt5/include/QtCore/qstring.h:214:14: note: QString::QString(const QChar*, int)
Makefile:2564: recipe for target 'main.o' failed
make: *** [main.o] Error 1
事情是......在代码的这个特定区域,我没有从 int 到 QString 的转换!
class Core : public QObject
{
Q_OBJECT
private:
static Core *instance_;
QHash <int, Channel*> channels_;
int currentChannelId_;
QString computerName_;
QString projectDirectory_;
Definitions::kPlayerStatus player_;
QHash<int, Media*> medias_;
QString userEmail_;
QString userPassword_;
QString userPasswordEncrypted_;
bool logged_;
Core(){
Channel *channel = new Channel; // This is the error line.
channels_.insert(channel->getId(),channel);
currentChannelId_ = channel->getId();
player_ = Definitions::kStopped;
logged_ = false;
}
Core(const Core&);
Core& operator=(const Core&);
/* Protect destructor.
* Deletes all elements allocated in the Document.
*/
~Core()
{
// Delete channels
foreach (Channel *c, channels_)
delete c;
}
(...)
}
这是 Channel 构造函数:
class Channel : public QObject
{
Q_OBJECT
private:
static int countChannel_;
int idChannel_;
QString label_;
int currentMediaId_;
int totalTime_;
int order_;
QHash<int, Media*> medias_;
signals:
(...)
public:
Channel(int id = -1, int order = -1, int totalTime = -1, QString label = NULL) {
if(id==-1){
idChannel_ = countChannel_++;
}else{
idChannel_ = id;
countChannel_ = countChannel_ <= id ? id+1 : countChannel_;
}
order_ = order == -1 ? idChannel_ : order;
totalTime_ = totalTime == -1 ? 0 : totalTime;
label_ = label == NULL ? QString("Channel %1").arg(idChannel_+1) : label;
}
/* Protect destructor.
* Deletes all elements allocated in the Channel.
*/
~Channel()
{
// Delete medias
foreach (Media *m, medias_)
delete m;
}
(...)
}
这里是 make 调用的命令:
/usr/bin/g++ -c -pipe -marm -mfpu=vfp -mtune=arm1176jzf-s -march=armv6zk -mabi=aapcs-linux -mfloat-abi=hard -O2 -std=c++0x -Wall -W -D_REENTRANT -fPIE -DQT_NO_SSL -DQT_NO_DEBUG -DQT_MULTIMEDIAWIDGETS_LIB -DQT_MULTIMEDIA_LIB -DQT_WIDGETS_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_XML_LIB -DQT_CORE_LIB -I../../vodas_desktop -I. -I/usr/local/qt5/include -I/usr/local/qt5/include/QtMultimediaWidgets -I/usr/local/qt5/include/QtMultimedia -I/usr/local/qt5/include/QtWidgets -I/usr/local/qt5/include/QtGui -I/usr/local/qt5/include/QtNetwork -I/usr/local/qt5/include/QtXml -I/usr/local/qt5/include/QtCore -I. -I/opt/vc/include -I/opt/vc/include/interface/vcos/pthreads -I/opt/vc/include/interface/vmcs_host/linux -I/usr/local/qt5/mkspecs/devices/linux-rasp-pi-g++ -o main.o ../main.cpp
那么……有什么想法吗?我不知道出了什么问题。我的代码在 ubuntu 和 Windows 上编译时没有出现此错误消息。
最佳答案
QString
的默认参数无效:
QString label = NULL
NULL
只是 0 的宏,因此您实际上是说 QString label = 0
。 QString
没有定义从 int
创建 QString
的方法,这是您出错的原因 - 在大多数平台上我猜测 QString(const char *)
构造函数将通过从 0
到 const char *
的隐式转换被调用。
看起来你的 pi 无法弄清楚如何隐式转换 0
。将其更改为 QString label = ""
、QString label = QString()
或类似内容。
关于c++ - 尝试在树莓派上部署 qt5 应用程序时出现奇怪的错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/29951044/