我需要在模拟屏幕上显示一个字符串.为此,我应该从现有的Filename.txt / Filename.csv文件中读取文本. text参数更新,如下面的代码所示.我需要从文本文件中访问该字符串并在MarqueeText元素中使用它. Accessed字符串应在MarqueeText元素的文本字段中使用.
MarqueeText {
id:scrolltext
width: 255
height: 48
anchors.verticalCenter: parent.horizontalCenter
text: //i need to access the string in text file to be displayed
}
请帮我解决一下这个.谢谢.
解决方法
按照Wiki页面阅读有关使用QML访问文件的信息.诺基亚维基论坛
http://web.archive.org/web/20150227025348/http://developer.nokia.com/community/wiki/Reading_and_writing_files_in_QML
摘要：
创建自定义QML类型FileIO：
fileio.h
#ifndef FILEIO_H
#define FILEIO_H
#include <QObject>
class FileIO : public QObject
{
Q_OBJECT
public:
Q_PROPERTY(QString source
READ source
WRITE setSource
NOTIFY sourceChanged)
explicit FileIO(QObject *parent = 0);
Q_INVOKABLE QString read();
Q_INVOKABLE bool write(const QString& data);
QString source() { return mSource; };
public slots:
void setSource(const QString& source) { mSource = source; };
signals:
void sourceChanged(const QString& source);
void error(const QString& msg);
private:
QString mSource;
};
#endif // FILEIO_H
fileio.cpp
#include "fileio.h"
#include <QFile>
#include <QTextStream>
FileIO::FileIO(QObject *parent) :
QObject(parent)
{
}
QString FileIO::read()
{
if (mSource.isEmpty()){
emit error("source is empty");
return QString();
}
QFile file(mSource);
QString fileContent;
if ( file.open(QIODevice::ReadOnly) ) {
QString line;
QTextStream t( &file );
do {
line = t.readLine();
fileContent += line;
} while (!line.isNull());
file.close();
} else {
emit error("Unable to open the file");
return QString();
}
return fileContent;
}
bool FileIO::write(const QString& data)
{
if (mSource.isEmpty())
return false;
QFile file(mSource);
if (!file.open(QFile::WriteOnly | QFile::Truncate))
return false;
QTextStream out(&file);
out << data;
file.close();
return true;
}
注册新的QML类型：
#include "fileio.h"
Q_DECL_EXPORT int main(int argc,char *argv[])
{
...
qmlRegisterType<FileIO,1>("FileIO",1,"FileIO");
...
}
实际QML用法：
import QtQuick 1.1
import FileIO 1.0
Rectangle {
width: 360
height: 360
Text {
id: myText
text: "Hello World"
anchors.centerIn: parent
}
FileIO {
id: myFile
source: "my_file.txt"
onError: console.log(msg)
}
Component.onCompleted: {
console.log( "WRITE"+ myFile.write("TEST"));
myText.text = myFile.read();
}
}
