Merge pull request #3417 from nyalldawson/expression_line_edit

Expression line edit widget
qgis · Aug 21, 2016 · b101510 · b101510
2 parents 86feb6d + c468a04
commit b101510
Show file tree

Hide file tree

Showing 11 changed files with 556 additions and 21 deletions.
diff --git a/python/gui/gui.sip b/python/gui/gui.sip
@@ -70,6 +70,7 @@
 %Include qgsexpressionbuilderdialog.sip
 %Include qgsexpressionbuilderwidget.sip
 %Include qgsexpressionhighlighter.sip
+%Include qgsexpressionlineedit.sip
 %Include qgsexpressionselectiondialog.sip
 %Include qgsextentgroupbox.sip
 %Include qgsexternalresourcewidget.sip

diff --git a/python/gui/qgsexpressionlineedit.sip b/python/gui/qgsexpressionlineedit.sip
@@ -0,0 +1,90 @@
+/** \ingroup gui
+ * @class QgsExpressionLineEdit
+ * @brief The QgsExpressionLineEdit widget includes a line edit for entering expressions
+ * together with a button to open the expression creation dialog.
+ *
+ * This widget is designed for use in contexts where no layer fields are available for
+ * use in an expression. In contexts where the expression is directly associated with
+ * a layer and fields can be used, then QgsFieldExpressionWidget is a more appropriate
+ * choice as it gives users direct access to select fields from a drop down list.
+ * @note added in QGIS 3.0
+ */
+
+class QgsExpressionLineEdit : QWidget
+{
+%TypeHeaderCode
+#include "qgsexpressionlineedit.h"
+%End
+
+  public:
+
+    /**
+     * Constructor for QgsExpressionLineEdit.
+     * @param parent parent widget
+     */
+    explicit QgsExpressionLineEdit( QWidget *parent /TransferThis/ = nullptr );
+        /** Sets the title used in the expression builder dialog
+     * @param title dialog title
+     * @see expressionDialogTitle()
+     */
+    void setExpressionDialogTitle( const QString& title );
+
+    /** Returns the title used for the expression dialog.
+     * @see setExpressionDialogTitle()
+     */
+    QString expressionDialogTitle() const;
+
+    /** Sets whether the widget should show a multiline text editor.
+     * @param multiLine set to true to show multiline editor, or false
+     * to show single line editor (the default).
+     */
+    void setMultiLine( bool multiLine );
+
+    /** Set the geometry calculator used in the expression dialog.
+     * @param distanceArea calculator
+     */
+    void setGeomCalculator( const QgsDistanceArea &distanceArea );
+
+    /** Sets a layer associated with the widget. Required in order to get the fields and values
+      * from the layer.
+      * @param layer vector layer
+      */
+    void setLayer( QgsVectorLayer* layer );
+
+    /** Returns the current expression shown in the widget.
+     * @see setExpression()
+     */
+    QString expression() const;
+
+    /**
+      * Returns true if the current expression is valid.
+      * @param expressionError will be set to any generated error message if specified
+      */
+    bool isValidExpression( QString *expressionError /Out/ = nullptr ) const;
+
+    /**
+     * Register an expression context generator class that will be used to retrieve
+     * an expression context for the widget.
+     * @param generator A QgsExpressionContextGenerator class that will be used to
+     *                  create an expression context when required.
+     */
+    void registerExpressionContextGenerator( const QgsExpressionContextGenerator* generator );
+
+  signals:
+
+    /** Emitted when the expression is changed.
+     * @param expression new expression
+     */
+    void expressionChanged( const QString& expression );
+
+  public slots:
+
+    /** Sets the current expression to show in the widget.
+     * @param expression expression string
+     * @see expression()
+     */
+    void setExpression( const QString& expression );
+
+  protected:
+    void changeEvent( QEvent* event );
+};
diff --git a/src/gui/CMakeLists.txt b/src/gui/CMakeLists.txt
@@ -208,6 +208,7 @@ SET(QGIS_GUI_SRCS
   qgsexpressionbuilderdialog.cpp
   qgsexpressionbuilderwidget.cpp
   qgsexpressionhighlighter.cpp
+  qgsexpressionlineedit.cpp
   qgsexpressionselectiondialog.cpp
   qgsextentgroupbox.cpp
   qgsexternalresourcewidget.cpp
@@ -365,6 +366,7 @@ SET(QGIS_GUI_MOC_HDRS
   qgsexpressionbuilderdialog.h
   qgsexpressionbuilderwidget.h
   qgsexpressionhighlighter.h
+  qgsexpressionlineedit.h
   qgsexpressionselectiondialog.h
   qgsextentgroupbox.h
   qgsexternalresourcewidget.h

diff --git a/src/gui/qgscodeeditor.cpp b/src/gui/qgscodeeditor.cpp
@@ -31,7 +31,6 @@ QgsCodeEditor::QgsCodeEditor( QWidget *parent, const QString& title, bool foldin
   if ( !parent && mWidgetTitle.isEmpty() )
   {
     setWindowTitle( "Text Editor" );
-    setMinimumSize( 800, 300 );
   }
   else
   {

diff --git a/src/gui/qgsexpressionlineedit.cpp b/src/gui/qgsexpressionlineedit.cpp
@@ -0,0 +1,221 @@
+/***************************************************************************
+   qgsexpressionlineedit.cpp
+    ------------------------
+   Date                 : 18.08.2016
+   Copyright            : (C) 2016 Nyall Dawson
+   Email                : nyall dot dawson at gmail dot com
+***************************************************************************
+*                                                                         *
+*   This program is free software; you can redistribute it and/or modify  *
+*   it under the terms of the GNU General Public License as published by  *
+*   the Free Software Foundation; either version 2 of the License, or     *
+*   (at your option) any later version.                                   *
+*                                                                         *
+***************************************************************************/
+
+#include "qgsexpressionlineedit.h"
+#include "qgsfilterlineedit.h"
+#include "qgsexpressioncontext.h"
+#include "qgsapplication.h"
+#include "qgsexpressionbuilderdialog.h"
+#include "qgsexpressioncontextgenerator.h"
+#include "qgscodeeditorsql.h"
+#include <QHBoxLayout>
+#include <QVBoxLayout>
+#include <QToolButton>
+
+
+QgsExpressionLineEdit::QgsExpressionLineEdit( QWidget *parent )
+    : QWidget( parent )
+    , mLineEdit( nullptr )
+    , mCodeEditor( nullptr )
+    , mExpressionDialogTitle( tr( "Expression dialog" ) )
+    , mDa( nullptr )
+    , mExpressionContextGenerator( nullptr )
+    , mLayer( nullptr )
+{
+  mButton = new QToolButton();
+  mButton->setSizePolicy( QSizePolicy::Minimum, QSizePolicy::Minimum );
+  mButton->setIcon( QgsApplication::getThemeIcon( "/mIconExpression.svg" ) );
+  connect( mButton, SIGNAL( clicked() ), this, SLOT( editExpression() ) );
+
+  //sets up layout
+  setMultiLine( false );
+
+  mExpressionContext = QgsExpressionContext();
+  mExpressionContext << QgsExpressionContextUtils::globalScope()
+  << QgsExpressionContextUtils::projectScope();
+}
+
+void QgsExpressionLineEdit::setExpressionDialogTitle( const QString& title )
+{
+  mExpressionDialogTitle = title;
+}
+
+void QgsExpressionLineEdit::setMultiLine( bool multiLine )
+{
+  QString exp = expression();
+
+  if ( multiLine && !mCodeEditor )
+  {
+    mCodeEditor = new QgsCodeEditorSQL();
+    mCodeEditor->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
+    delete mLineEdit;
+    mLineEdit = nullptr;
+
+    QHBoxLayout* newLayout = new QHBoxLayout();
+    newLayout->setContentsMargins( 0, 0, 0, 0 );
+    newLayout->addWidget( mCodeEditor );
+
+    QVBoxLayout* vLayout = new QVBoxLayout();
+    vLayout->addWidget( mButton );
+    vLayout->addStretch();
+    newLayout->addLayout( vLayout );
+
+    delete layout();
+    setLayout( newLayout );
+
+    setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );
+
+    setFocusProxy( mCodeEditor );
+    connect( mCodeEditor, SIGNAL( textChanged() ), this, SLOT( expressionEdited() ) );
+
+    setExpression( exp );
+  }
+  else if ( !multiLine && !mLineEdit )
+  {
+    delete mCodeEditor;
+    mCodeEditor = nullptr;
+    mLineEdit = new QgsFilterLineEdit();
+    mLineEdit->setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Minimum );
+
+    QHBoxLayout* newLayout = new QHBoxLayout();
+    newLayout->setContentsMargins( 0, 0, 0, 0 );
+    newLayout->addWidget( mLineEdit );
+    newLayout->addWidget( mButton );
+
+    delete layout();
+    setLayout( newLayout );
+
+    setSizePolicy( QSizePolicy::Expanding, QSizePolicy::Minimum );
+
+    setFocusProxy( mLineEdit );
+    connect( mLineEdit, SIGNAL( textChanged( QString ) ), this, SLOT( expressionEdited( QString ) ) );
+
+    setExpression( exp );
+  }
+}
+
+void QgsExpressionLineEdit::setGeomCalculator( const QgsDistanceArea &da )
+{
+  mDa.reset( new QgsDistanceArea( da ) );
+}
+
+void QgsExpressionLineEdit::setLayer( QgsVectorLayer* layer )
+{
+  mLayer = layer;
+}
+
+QString QgsExpressionLineEdit::expression() const
+{
+  if ( mLineEdit )
+    return mLineEdit->text();
+  else if ( mCodeEditor )
+    return mCodeEditor->text();
+
+  return QString();
+}
+
+bool QgsExpressionLineEdit::isValidExpression( QString *expressionError ) const
+{
+  QString temp;
+  return QgsExpression::isValid( expression(), &mExpressionContext, expressionError ? *expressionError : temp );
+}
+
+void QgsExpressionLineEdit::registerExpressionContextGenerator( const QgsExpressionContextGenerator* generator )
+{
+  mExpressionContextGenerator = generator;
+}
+
+void QgsExpressionLineEdit::setExpression( const QString& newExpression )
+{
+  if ( mLineEdit )
+    mLineEdit->setText( newExpression );
+  else if ( mCodeEditor )
+    mCodeEditor->setText( newExpression );
+}
+
+void QgsExpressionLineEdit::editExpression()
+{
+  QString currentExpression = expression();
+
+  QgsExpressionContext context = mExpressionContextGenerator ? mExpressionContextGenerator->createExpressionContext() : mExpressionContext;
+
+  QgsExpressionBuilderDialog dlg( mLayer, currentExpression, this, "generic", context );
+  if ( !mDa.isNull() )
+  {
+    dlg.setGeomCalculator( *mDa );
+  }
+  dlg.setWindowTitle( mExpressionDialogTitle );
+
+  if ( dlg.exec() )
+  {
+    QString newExpression = dlg.expressionText();
+    setExpression( newExpression );
+  }
+}
+
+void QgsExpressionLineEdit::expressionEdited()
+{
+  emit expressionChanged( expression() );
+}
+
+void QgsExpressionLineEdit::expressionEdited( const QString& expression )
+{
+  updateLineEditStyle( expression );
+  emit expressionChanged( expression );
+}
+
+void QgsExpressionLineEdit::changeEvent( QEvent* event )
+{
+  if ( event->type() == QEvent::EnabledChange )
+  {
+    updateLineEditStyle( expression() );
+  }
+}
+
+void QgsExpressionLineEdit::updateLineEditStyle( const QString& expression )
+{
+  if ( !mLineEdit )
+    return;
+
+  QPalette palette;
+  if ( !isEnabled() )
+  {
+    palette.setColor( QPalette::Text, Qt::gray );
+  }
+  else
+  {
+    bool isValid = true;
+    if ( !expression.isEmpty() )
+    {
+      isValid = isExpressionValid( expression );
+    }
+    if ( !isValid )
+    {
+      palette.setColor( QPalette::Text, Qt::red );
+    }
+    else
+    {
+      palette.setColor( QPalette::Text, Qt::black );
+    }
+  }
+  mLineEdit->setPalette( palette );
+}
+
+bool QgsExpressionLineEdit::isExpressionValid( const QString& expressionStr )
+{
+  QgsExpression expression( expressionStr );
+  expression.prepare( &mExpressionContext );
+  return !expression.hasParserError();
+}