HowTo: Using the SD Linear Gauge Control for Smart Devices

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Many times information needs to be shown in a context of range values. To do so in the Smart Devices Generator there is the Linear Gauge Control. 

This article shows an example of how to use the control and explains some facts about it.

Step 1:  Create the Transaction

Create the following Transaction and apply the Work With for Smart Devices object (WWSD) (see about this here: Applying Work With for Smart Devices Pattern).


Step 2: Create the Structured Data Type (SDT) to load the information

This control loads the information it needs to build the ranges from an SDT. This SDT is automatically generated by GeneXus when control is applied.

GaugeSDT Structure


Title Is the text that will be displayed above the control.
Height Is the Height for the range bars.
MaxValue Is the max value the range will have (total). Should be equal to:  MinValue + Sum(Length).
MinValue Is the min value the range will have (total).
Value The current value.
ShowMinMax Is a boolean flag which enables/disables if the minimum and maximum values are show within the control.


Ranges (for each range):

Color A string value which has the hexa code for a color. This color will be associated with the range.
Name The name the range will have.
Length This will define the lenght of the range.


The ranges are defined in order. If you want to define a Low, Medium and High you should defined them on the same order because if not there are not going to be seen as you want.

Step 3: Create the Data Provider to fill the SDT

Create the getRanges Data Provider to fill the SDT, as follow:

        Title = ''
	Height = 10
	MaxValue = 100
	MinValue = 20
	Value = TrnCustomersNumeric
	ShowMinMax = false
			Color = "#0000FF"
			Name = "Low"
			Length = 20
			Color = "#008000"
			Name = "Medium"
			Length = 40
			Color = "#660000"
			Name = "High"
			Length = 20


Step 4: Define variables in the WWSD

In a Work With for Smart Devices we can´t have variables from SDTs. We will load a Character variable with a representation of the SDT in JSon.

a. Lets do the following procedure (getRangesChar). This procedure will call the DataProvider defined in step 3, then will apply the .ToJson() function.

&gaugSDT = getRanges(&CustomerId)
&chargaug = &gaugSDT.ToJson()



parm(in: &CustomerId,out: &chargaug);

b. Define a new variable in the WWSD

    MyChar= VarChar(1000)

As shown in the image below:




c. Add the variable In the layout of the WWSD and set the Control Type property to SDLinearGauge




In the "Events" section, write the following code:

Event Refresh
     &CustomerInfor = getRangesChar(TrnCustomersId)

As said before in a near future when we suppoort variables based on SDT the procedure defined in Step 4 is not going to be needed, because you will be able to call the Data Provider from  the load code of the variable.

Step 5: Done!

Press F5 and test the Linear Gauge Control!


If you want to change the size or forecolor (*) of text displayed in this control, you can do it in the Theme Class associated to the control in the layout.
(*) Available in Android from GeneXus X Evolution 3 Upgrade 4







Start Video Work With for Smart Devices – General Aspects and List layout
Start Video WorkWith for Smart Devices – Detail Layout

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