03 SeekBarPreference

The preference, which is implemented in the class SeekBarPreference, does provides the possibility to select a Float or Integer value from a continous range via a SeekBar. The SeekBar is shown within a dialog and the selected value only becomes persisted when the user closes the dialog affirmatively. The preference allows to specify a minimum and maximum value and the number of decimals of the Float values, which can be selected by the SeekBar. If integer values should be selected by the preference, the number of decimals can be set to 0. Furthermore, the step size, the value is increased or decreased by, when the SeekBar is moved, can be specified. Optionally, the currently selected value, using a customizable unit, can be shown within the dialog.

3.1 Getter and setter methods

When a SeekBarPreference is instantiated programmatically, its properties can be set or retrieved by using the setter and getter methods, which are listed in the table below. As the class is extended from the class DialogPreference, the methods, which have been already discussed in the previous section, are also available.

Getter and setter methods	Description	Default value	Restrictions
getValue():float setValue(float):void	Returns or sets the currently persisted value of the preference. If a value is set, it is instantly persisted. If a step size is set, the value will be eventually rounded.	0.0	none
getMinValue():int setMinValue(int):void	Returns or sets the minimum value of the preference.	0.0	The value must be less than the maximum value.
getMaxValue():int setMaxValue(int):void	Returns or sets the maximum value of the preference.	100.0	The value must be greater than the minimum value.
getRange():int	Returns the range of values, the preference allows to choose from (maximum value - minimum value).	100.0	none
getStepSize():int setStepSize(int):void	Returns or sets the step size, the value is increased or decreased by, when the user moves the preference's seek bar.	-1	The value must be -1, if no step size should be used, or it must be at minimum 1 and at maximum the value of the method getRange().
getDecimals():int setDecimals(int):void	Returns or sets the number of decimals of the floating point numbers, which can be chosen by using the preference.	1	The value must be at least 0.
getUnit():CharSequence setUnit(CharSequence):void setUnit(int):void	Returns or sets the unit, which is appended to the preference's currently chosen value for textual representation. It the unit is set to null, no unit is appended.	null	none
getFloatingPointSeparator():CharSequence setFloatingPointSeparator(CharSequence):void setFloatingPointSeparator(int):void	Returns or sets the symbol, which is used to separate floating point numbers for textual representation. If the separator is set to null, the default symbol, depending on the device's locale, is used.	null	If not null, the string must have a size of 1.
isProgressShown():boolean showProgress(boolean):void	Returns or sets, whether the currently chosen value of the preference's seek bar is shown, or not.	true	none
getSummaries():CharSequence[] setSummaries(CharSequence[]):void	Returns or sets the summaries, which should be shown as the preference's summary, depending on the currently persisted value. For example, if the array's dimension is 2, the first summary will be shown if the value is between 0% and 49% of the whole range and the second summary will be shown if the value is between 50% and 100% of the range. If the array is set to null, no summaries will be shown depending on the currently persisted value.	null	none

3.2. XML attributes

If a SeekBarPreference is created by beeing specified within a XML resource file, XML attributes can be used to customize the preference's behaviour and appearance. Besides the inherited attributes, which are defined by the Android API, the library does provide various custom attributes, which can be used to set the same attributes as the setter methods mentioned in the previous section. The custom attributes, respectively the inherited attributes, whose semantic is modified by the library, are defined within the file /res/values/attrs.xml. In the following two sections all custom attributes and the most important inherited attributes will be introduced. The following table shows the custom attributes of the preference.

XML attribute	Description	Format
android:defaultValue	The preference's default value. If a step size is set, the value will be eventually rounded.	float
android:max	The maximum value of the preference.	integer
custom:min	The minimum value of the preference.	integer
custom:decimals	The number of decimals of the floating point numbers which can be chosen by using the preference. If the value is set to 0, only integer values can be chosen.	integer
custom:stepSize	The step size the preference's current value is increased or decreased by, when the user moves the seek bar. If the value is set to -1 no step size is used.	integer
custom:unit	The unit, which is appended to the preference's current value for textual representation. If the unit is null, no unit is appended.	string
custom:floatingPointSeparator	The symbol, which is used to separate floating point numbers for textual representation. If the string is null, the default separator, depending on the system's locale, is used.	string
custom:showProgress	Defines, whether the current chosen value of the preference's seek bar should be shown, or not.	boolean