The Text field is a composable function in Jetpack Compose that allows users to input text. It's very customizable text and is built with many optional parameters to enhance the flexibility of the text input fields.
Where is Text field used?
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Core Parameters:
value: TextFieldValue
Represents the current value of the Text Field. It can be a simple string or a more complex object like Text field value which holds both the text and the cursor position. This allows for more control over the behavior of the text field.
onValueChange: (TextFieldValue) -> Unit
A lambda that is called whenever the content of the Text Field changes. It's important to update the state holding the text inside this function.
Customization Parameters:
modifier: Modifier
You can use Modifier to customize the appearance or behavior of the Text Field. For example, you can add padding, change the size, or define its alignment.
enabled: Boolean
Controls whether the Text Field is enabled or disabled. If you disable it, the user can't interact with it.
read Only: Boolean
When set to true, the text can be selected and copied, but not edited. This is useful for displaying text that shouldn't be modified by the user.
Text style: Text style
Defines how the text inside the Text Field looks, such as the font size, color, and weight.
Visual Customization:
label: (@Composable () -> Unit)?
A composable that defines a label for the Text Field, usually used to show the name of the field (e.g., "Username"). It appears inside the text field and moves above when the user types.
placeholder: (@Composable () -> Unit)?
A placeholder is shown when the Text Field is empty, giving a hint to the user about what kind of input is expected.
Leading icon and Trailing icon: (@Composable () -> Unit)?
Allows you to add icons or any composable before or after the input text, respectively. For example, you could place a search icon in the Leading icon.
prefix and suffix: (@Composable () -> Unit)?
Similar to leading and trailing icons but more focused on text-like components, such as currency symbols (prefix) or units (suffix).
Error and Validation:
isError: Boolean
When set to true, it marks the text field as having an error. You can change the appearance of the field (e.g., showing a red border) when there is an error.
Supporting text: (@Composable () -> Unit)?
Used to display additional supporting text below the Text Field, like error messages or hints.
Text Transformation:
Visual transformation: Visual transformation
This allows for modifying the displayed text without changing the actual value. For example, you can use Password Visual Transformation() to hide the characters of a password.
Keyboard and Input Behavior:
Keyboard options: Keyboard Options
Defines options for the software keyboard. You can specify the type of keyboard (e.g., numeric or text) or actions like "Done", "Next", or "Search".
keyboard Actions: Keyboard actions
This lets you handle events like when the user presses "Enter" or "Done" on the keyboard, allowing for actions like submitting a form.
Line and Text Handling:
Single line: Boolean
When set to true, the Text field only allows one line of input. This is used for fields like usernames or passwords.
Max lines: Int
Defines the maximum number of lines the text field can have. It defaults to Int.MAX_VALUE when Single line is false.
Min lines: Int
Defines the minimum number of lines the text field will display.
Shape and Colors:
shape: Shape
Specifies the shape of the Text Field, like rounded corners. You can use predefined shapes or define your own.
colors: Text Field colors
Allows you to customize the colors of different elements of the Text field, such as the text, cursor, background, and more.
Interaction Source:
Interaction source: Mutable Interaction Source?
Tracks the user's interaction with the Text Field, such as focus or clicks. You can use this to add animations or other effects based on user interaction.