Major updates to ComboBox:

- Essentially a graphical interface to dict; all items have text and value
- Assigns previously-selected text after list is cleared and repopulated
- Get, set current value
This commit is contained in:
Luke Campagnola 2013-12-27 21:06:31 -05:00
parent 9de3011556
commit 2c2135a49f
2 changed files with 230 additions and 15 deletions

View File

@ -1,41 +1,212 @@
from ..Qt import QtGui, QtCore
from ..SignalProxy import SignalProxy
from ..ordereddict import OrderedDict
from ..python2_3 import asUnicode
class ComboBox(QtGui.QComboBox):
"""Extends QComboBox to add extra functionality.
- updateList() - updates the items in the comboBox while blocking signals, remembers and resets to the previous values if it's still in the list
* Handles dict mappings -- user selects a text key, and the ComboBox indicates
the selected value.
* Requires item strings to be unique
* Remembers selected value if list is cleared and subsequently repopulated
* setItems() replaces the items in the ComboBox and blocks signals if the
value ultimately does not change.
"""
def __init__(self, parent=None, items=None, default=None):
QtGui.QComboBox.__init__(self, parent)
self.currentIndexChanged.connect(self.indexChanged)
self._ignoreIndexChange = False
#self.value = default
self._chosenText = None
self._items = OrderedDict()
if items is not None:
self.addItems(items)
self.setItems(items)
if default is not None:
self.setValue(default)
def setValue(self, value):
ind = self.findText(value)
"""Set the selected item to the first one having the given value."""
text = None
for k,v in self._items.items():
if v == value:
text = k
break
if text is None:
raise ValueError(value)
self.setText(text)
def setText(self, text):
"""Set the selected item to the first one having the given text."""
ind = self.findText(text)
if ind == -1:
return
raise ValueError(text)
#self.value = value
self.setCurrentIndex(ind)
def updateList(self, items):
prevVal = str(self.currentText())
try:
self.setCurrentIndex(ind)
def value(self):
"""
If items were given as a list of strings, then return the currently
selected text. If items were given as a dict, then return the value
corresponding to the currently selected key. If the combo list is empty,
return None.
"""
if self.count() == 0:
return None
text = asUnicode(self.currentText())
return self._items[text]
def ignoreIndexChange(func):
# Decorator that prevents updates to self._chosenText
def fn(self, *args, **kwds):
prev = self._ignoreIndexChange
self._ignoreIndexChange = True
try:
ret = func(self, *args, **kwds)
finally:
self._ignoreIndexChange = prev
return ret
return fn
def blockIfUnchanged(func):
# decorator that blocks signal emission during complex operations
# and emits currentIndexChanged only if the value has actually
# changed at the end.
def fn(self, *args, **kwds):
prevVal = self.value()
blocked = self.signalsBlocked()
self.blockSignals(True)
try:
ret = func(self, *args, **kwds)
finally:
self.blockSignals(blocked)
# only emit if the value has changed
if self.value() != prevVal:
self.currentIndexChanged.emit(self.currentIndex())
return ret
return fn
@ignoreIndexChange
@blockIfUnchanged
def setItems(self, items):
"""
*items* may be a list or a dict.
If a dict is given, then the keys are used to populate the combo box
and the values will be used for both value() and setValue().
"""
prevVal = self.value()
self.blockSignals(True)
try:
self.clear()
self.addItems(items)
self.setValue(prevVal)
finally:
self.blockSignals(False)
if str(self.currentText()) != prevVal:
# only emit if we were not able to re-set the original value
if self.value() != prevVal:
self.currentIndexChanged.emit(self.currentIndex())
def items(self):
return self.items.copy()
def updateList(self, items):
# for backward compatibility
return self.setItems(items)
def indexChanged(self, index):
# current index has changed; need to remember new 'chosen text'
if self._ignoreIndexChange:
return
self._chosenText = asUnicode(self.currentText())
def setCurrentIndex(self, index):
QtGui.QComboBox.setCurrentIndex(self, index)
def itemsChanged(self):
# try to set the value to the last one selected, if it is available.
if self._chosenText is not None:
try:
self.setText(self._chosenText)
except ValueError:
pass
@ignoreIndexChange
def insertItem(self, *args):
raise NotImplementedError()
#QtGui.QComboBox.insertItem(self, *args)
#self.itemsChanged()
@ignoreIndexChange
def insertItems(self, *args):
raise NotImplementedError()
#QtGui.QComboBox.insertItems(self, *args)
#self.itemsChanged()
@ignoreIndexChange
def addItem(self, *args, **kwds):
# Need to handle two different function signatures for QComboBox.addItem
try:
if isinstance(args[0], basestring):
text = args[0]
if len(args) == 2:
value = args[1]
else:
value = kwds.get('value', text)
else:
text = args[1]
if len(args) == 3:
value = args[2]
else:
value = kwds.get('value', text)
except IndexError:
raise TypeError("First or second argument of addItem must be a string.")
if text in self._items:
raise Exception('ComboBox already has item named "%s".' % text)
self._items[text] = value
QtGui.QComboBox.addItem(self, *args)
self.itemsChanged()
def setItemValue(self, name, value):
if name not in self._items:
self.addItem(name, value)
else:
self._items[name] = value
@ignoreIndexChange
@blockIfUnchanged
def addItems(self, items):
if isinstance(items, list):
texts = items
items = dict([(x, x) for x in items])
elif isinstance(items, dict):
texts = items.keys()
else:
raise TypeError("items argument must be list or dict.")
for t in texts:
if t in self._items:
raise Exception('ComboBox already has item named "%s".' % t)
for k,v in items.items():
self._items[k] = v
QtGui.QComboBox.addItems(self, texts)
self.itemsChanged()
@ignoreIndexChange
def clear(self):
self._items = OrderedDict()
QtGui.QComboBox.clear(self)
self.itemsChanged()

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@ -0,0 +1,44 @@
import pyqtgraph as pg
pg.mkQApp()
def test_combobox():
cb = pg.ComboBox()
items = {'a': 1, 'b': 2, 'c': 3}
cb.setItems(items)
cb.setValue(2)
assert str(cb.currentText()) == 'b'
assert cb.value() == 2
# Clear item list; value should be None
cb.clear()
assert cb.value() == None
# Reset item list; value should be set automatically
cb.setItems(items)
assert cb.value() == 2
# Clear item list; repopulate with same names and new values
items = {'a': 4, 'b': 5, 'c': 6}
cb.clear()
cb.setItems(items)
assert cb.value() == 5
# Set list instead of dict
cb.setItems(items.keys())
assert str(cb.currentText()) == 'b'
cb.setValue('c')
assert cb.value() == str(cb.currentText())
assert cb.value() == 'c'
cb.setItemValue('c', 7)
assert cb.value() == 7
if __name__ == '__main__':
cb = pg.ComboBox()
cb.show()
cb.setItems({'': None, 'a': 1, 'b': 2, 'c': 3})
def fn(ind):
print "New value:", cb.value()
cb.currentIndexChanged.connect(fn)