Filter a collection

Create custom filters to make it easier for the user to access certain data. Filters allow you to display the data in your collection based on a condition. 

Concretely these filters act on the content of the component Collection / List : they allow to display only the elements that meet a condition. This condition is freely determined. Each element is evaluated according to this condition and is displayed only if the condition is met. 

In the Paris City Guide application, the user has the option to filter the list of good deals by category: Food, Drinks, Museum or Outdoor.

Display categories

Create a Text variable (it's called selected_type in the example below) from the PandaSuite database: this variable allows you to save the selected category so you can use it when creating the filter condition.

When the user selects one of the categories, change the value of this variable. 

Add an action:  Interact with a database > PandaSuite database > Modify the data > selected_type

Set its value manually. Below the user has selected the category Food, the value entered is Food.

Now create the condition that displays items based on the selected category. 

In our example for a good plan to be displayed, the filter condition must be met. This one is composed of 2 expressions: 

• If the user has not selected a category (the value of the variable selected_type is unknown or empty) 
• OR if the user-selected category (the value of the variable selected_type) matches the category of the current element 

Go to the properties of your component Collection/List. Click Filter and the +  button;

Multi-selection of filters 

In the previous example, the user can only select one category at a time. Therefore, the variable is of type Text.

If you want the user to be able to select more than one, you need to choose a different type of variable: Array. Indeed the table allows you to add one or more selected categories. 

At the level of your filter condition, you need to adapt your expression: 

• If the user did not select a category (the value of the variable selected_type is unknown or empty) 
• OR if the user selected category table contains the category of the current item

Filter without user selection

In the previous examples, the filter was tied to a user selection. Nevertheless this is not a requirement. 

For example, you can choose to display only restaurants. In which case the filter condition becomes: if the category of the current item is Food.