com.trolltech.qt.core
Class QTranslator

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QObject
                  extended by com.trolltech.qt.core.QTranslator
All Implemented Interfaces:
QtJambiInterface

public class QTranslator
extends QObject

The QTranslator class provides internationalization support for text output. An object of this class contains a set of translations from a source language to a target language. QTranslator provides functions to look up translations in a translation file. Translation files are created using Qt Linguist.

The most common use of QTranslator is to: load a translation file, install it using QApplication::installTranslator(), and use it via QObject::tr(). Here's the main() function from the Hello tr() example:

The following code example is written in c++.

int main(int argc, char *argv[])

{
    QApplication app(argc, argv);



    QTranslator translator;

    translator.load("hellotr_la");

    app.installTranslator(&translator);



    QPushButton hello(QPushButton::tr("Hello world!"));

    hello.resize(100, 30);

    hello.show();
    return app.exec();
}
Note that the translator must be created before the application's widgets.

Most applications will never need to do anything else with this class. The other functions provided by this class are useful for applications that work on translator files.

Looking up Translations

It is possible to look up a translation using translate() (as tr() and QApplication::translate() do). The translate() function takes up to three parameters: For example, the "Cancel" in a dialog might have "Anuluj" when the program runs in Polish (in this case the source text would be "Cancel"). The context would (normally) be the dialog's class name; there would normally be no comment, and the translated text would be "Anuluj".

But it's not always so simple. The Spanish version of a printer dialog with settings for two-sided printing and binding would probably require both "Activado" and "Activada" as translations for "Enabled". In this case the source text would be "Enabled" in both cases, and the context would be the dialog's class name, but the two items would have disambiguations such as "two-sided printing" for one and "binding" for the other. The disambiguation enables the translator to choose the appropriate gender for the Spanish version, and enables Qt to distinguish between translations.

Using Multiple Translations

Multiple translation files can be installed in an application. Translations are searched for in the reverse order in which they were installed, so the most recently installed translation file is searched for translations first and the earliest translation file is searched last. The search stops as soon as a translation containing a matching string is found.

This mechanism makes it possible for a specific translation to be "selected" or given priority over the others; simply uninstall the translator from the application by passing it to the QApplication::removeTranslator() function and reinstall it with QApplication::installTranslator(). It will then be the first translation to be searched for matching strings.

See also:
QApplication::installTranslator(), QApplication::removeTranslator(), QObject::tr(), QApplication::translate(), I18N Example, Hello tr() Example, Arrow Pad Example, and Troll Print Example.


Nested Class Summary
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QTranslator()
          Constructs an empty message file object with parent parent that is not connected to any file.
QTranslator(QObject parent)
          Constructs an empty message file object with parent parent that is not connected to any file.
 
Method Summary
 boolean isEmpty()
          Returns true if this translator is empty, otherwise returns false.
 boolean load(byte[] data)
          Loads the .qm file data data into the translator.
 boolean load(java.lang.String filename)
          Loads filename + suffix (".
 boolean load(java.lang.String filename, java.lang.String directory)
          Loads filename + suffix (".
 boolean load(java.lang.String filename, java.lang.String directory, java.lang.String search_delimiters)
          Loads filename + suffix (".
 boolean load(java.lang.String filename, java.lang.String directory, java.lang.String search_delimiters, java.lang.String suffix)
          Loads filename + suffix (".
 java.lang.String translate(java.lang.String context, java.lang.String sourceText)
          Returns the translation for the key (context, sourceText).
 java.lang.String translate(java.lang.String context, java.lang.String sourceText, java.lang.String disambiguation)
          Returns the translation for the key (context, sourceText, comment).
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QTranslator

public QTranslator()
Constructs an empty message file object with parent parent that is not connected to any file.


QTranslator

public QTranslator(QObject parent)
Constructs an empty message file object with parent parent that is not connected to any file.

Method Detail

load

public final boolean load(java.lang.String filename,
                          java.lang.String directory,
                          java.lang.String search_delimiters)
Loads filename + suffix (". m" if the suffix is not specified), which may be an absolute file name or relative to directory. Returns true if the translation is successfully loaded; otherwise returns false.

The previous contents of this translator object are discarded.

If the file name does not exist, other file names are tried in the following order:

  1. File name without suffix appended.
  2. File name with text after a character in search_delimiters stripped ("_." is the default for search_delimiters if it is an empty string) and suffix.
  3. File name stripped without suffix appended.
  4. File name stripped further, etc.
For example, an application running in the fr_CA locale (French-speaking Canada) might call load("foo.fr_ca", "/opt/foolib"). load() would then try to open the first existing readable file from this list:
  1. /opt/foolib/foo.fr_ca.qm
  2. /opt/foolib/foo.fr_ca
  3. /opt/foolib/foo.fr.qm
  4. /opt/foolib/foo.fr
  5. /opt/foolib/foo.qm
  6. /opt/foolib/foo


load

public final boolean load(java.lang.String filename,
                          java.lang.String directory)
Loads filename + suffix (". m" if the suffix is not specified), which may be an absolute file name or relative to directory. Returns true if the translation is successfully loaded; otherwise returns false.

The previous contents of this translator object are discarded.

If the file name does not exist, other file names are tried in the following order:

  1. File name without suffix appended.
  2. File name with text after a character in search_delimiters stripped ("_." is the default for search_delimiters if it is an empty string) and suffix.
  3. File name stripped without suffix appended.
  4. File name stripped further, etc.
For example, an application running in the fr_CA locale (French-speaking Canada) might call load("foo.fr_ca", "/opt/foolib"). load() would then try to open the first existing readable file from this list:
  1. /opt/foolib/foo.fr_ca.qm
  2. /opt/foolib/foo.fr_ca
  3. /opt/foolib/foo.fr.qm
  4. /opt/foolib/foo.fr
  5. /opt/foolib/foo.qm
  6. /opt/foolib/foo


load

public final boolean load(java.lang.String filename)
Loads filename + suffix (". m" if the suffix is not specified), which may be an absolute file name or relative to directory. Returns true if the translation is successfully loaded; otherwise returns false.

The previous contents of this translator object are discarded.

If the file name does not exist, other file names are tried in the following order:

  1. File name without suffix appended.
  2. File name with text after a character in search_delimiters stripped ("_." is the default for search_delimiters if it is an empty string) and suffix.
  3. File name stripped without suffix appended.
  4. File name stripped further, etc.
For example, an application running in the fr_CA locale (French-speaking Canada) might call load("foo.fr_ca", "/opt/foolib"). load() would then try to open the first existing readable file from this list:
  1. /opt/foolib/foo.fr_ca.qm
  2. /opt/foolib/foo.fr_ca
  3. /opt/foolib/foo.fr.qm
  4. /opt/foolib/foo.fr
  5. /opt/foolib/foo.qm
  6. /opt/foolib/foo


load

public final boolean load(java.lang.String filename,
                          java.lang.String directory,
                          java.lang.String search_delimiters,
                          java.lang.String suffix)
Loads filename + suffix (". m" if the suffix is not specified), which may be an absolute file name or relative to directory. Returns true if the translation is successfully loaded; otherwise returns false.

The previous contents of this translator object are discarded.

If the file name does not exist, other file names are tried in the following order:

  1. File name without suffix appended.
  2. File name with text after a character in search_delimiters stripped ("_." is the default for search_delimiters if it is an empty string) and suffix.
  3. File name stripped without suffix appended.
  4. File name stripped further, etc.
For example, an application running in the fr_CA locale (French-speaking Canada) might call load("foo.fr_ca", "/opt/foolib"). load() would then try to open the first existing readable file from this list:
  1. /opt/foolib/foo.fr_ca.qm
  2. /opt/foolib/foo.fr_ca
  3. /opt/foolib/foo.fr.qm
  4. /opt/foolib/foo.fr
  5. /opt/foolib/foo.qm
  6. /opt/foolib/foo


isEmpty

public boolean isEmpty()
Returns true if this translator is empty, otherwise returns false. This function works with stripped and unstripped translation files.


translate

public final java.lang.String translate(java.lang.String context,
                                        java.lang.String sourceText)
Returns the translation for the key (context, sourceText). If that fails, returns an empty string.


translate

public java.lang.String translate(java.lang.String context,
                                  java.lang.String sourceText,
                                  java.lang.String disambiguation)
Returns the translation for the key (context, sourceText, comment). If none is found, also tries (context, sourceText, ""). If that still fails, returns an empty string.


load

public final boolean load(byte[] data)
Loads the .qm file data data into the translator.

The data is not copied. The caller must be able to guarantee that data will not be deleted or modified.