Removing Underline in Jetpack Compose TextField Without Hiding Cursor

Jetpack Compose, Android’s modern UI toolkit, has revolutionized the way developers build user interfaces. One of its most used components is the TextField, which allows users to input text into an application. However, customizing a TextField to meet specific design requirements can sometimes be tricky, especially when it comes to removing the default underline without hiding the cursor.

In this blog post, we’ll explore how to achieve this customization in Jetpack Compose while maintaining a professional and seamless user experience. By the end of this guide, you’ll have a clear understanding of the steps and components involved in implementing a TextField without an underline, but with the cursor still visible.

Understanding the Default Behavior of TextField

By default, the TextField in Jetpack Compose comes with a built-in underline that serves as a visual indicator of the text input area. While this is helpful in many cases, certain design specifications might require a cleaner look without the underline.

Simply hiding the underline using a custom decoration can inadvertently lead to the cursor disappearing. This is because the underline and cursor are part of the same TextField decoration logic.

Key Considerations for Customizing TextField

Before we dive into the implementation, here are some points to consider:

  1. Separation of Style and Functionality: Removing the underline shouldn’t interfere with the cursor visibility or input behavior.

  2. Maintain Accessibility: Ensure that the customized TextField remains accessible for all users.

  3. Consistency: Align the design changes with the overall theme and design language of your application.

Steps to Remove Underline Without Hiding Cursor

Here’s a step-by-step guide to customize your TextField:

Step 1: Use BasicTextField

Instead of using the default TextField, opt for BasicTextField. This provides a more flexible way to design custom text input fields, as it gives you control over the decoration and styling without imposing default behaviors like the underline.

import androidx.compose.foundation.text.BasicTextField
import androidx.compose.runtime.Composable
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.text.TextStyle

@Composable
fun CustomTextField(
    value: String,
    onValueChange: (String) -> Unit
) {
    BasicTextField(
        value = value,
        onValueChange = onValueChange,
        textStyle = TextStyle(color = Color.Black),
        decorationBox = { innerTextField ->
            innerTextField() // Display the core text field
        }
    )
}

The BasicTextField gives you the freedom to define a decorationBox, which is where you can control the overall appearance without the default underline.

Step 2: Add a Custom Background or Border (Optional)

If you want to enhance the appearance of your TextField with a custom border or background, you can wrap the BasicTextField with Box and other layout elements:

import androidx.compose.foundation.background
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.padding
import androidx.compose.ui.Modifier
import androidx.compose.ui.graphics.Brush
import androidx.compose.ui.unit.dp

@Composable
fun CustomTextField(
    value: String,
    onValueChange: (String) -> Unit
) {
    Box(
        modifier = Modifier
            .background(Brush.horizontalGradient(listOf(Color.LightGray, Color.White)))
            .padding(8.dp)
    ) {
        BasicTextField(
            value = value,
            onValueChange = onValueChange,
            textStyle = TextStyle(color = Color.Black),
            decorationBox = { innerTextField ->
                innerTextField()
            }
        )
    }
}

This approach ensures that the cursor remains visible while providing flexibility to implement any custom decoration.

Step 3: Ensure Cursor Visibility

One common mistake when customizing TextField is forgetting to explicitly set the cursor properties. To ensure the cursor remains visible, you can use the cursorBrush parameter:

import androidx.compose.ui.graphics.SolidColor

@Composable
fun CustomTextField(
    value: String,
    onValueChange: (String) -> Unit
) {
    BasicTextField(
        value = value,
        onValueChange = onValueChange,
        textStyle = TextStyle(color = Color.Black),
        cursorBrush = SolidColor(Color.Blue),
        decorationBox = { innerTextField ->
            innerTextField()
        }
    )
}

By using SolidColor for the cursorBrush, you retain full control over the cursor color, ensuring it’s both visible and consistent with your app’s design.

Final Code Example

Combining all the steps above, here’s a complete implementation of a TextField without an underline and with a visible cursor:

@Composable
fun CustomTextField(
    value: String,
    onValueChange: (String) -> Unit
) {
    Box(
        modifier = Modifier
            .background(Color.LightGray)
            .padding(8.dp)
    ) {
        BasicTextField(
            value = value,
            onValueChange = onValueChange,
            textStyle = TextStyle(color = Color.Black),
            cursorBrush = SolidColor(Color.Blue),
            decorationBox = { innerTextField ->
                innerTextField()
            }
        )
    }
}

Testing and Debugging

After implementing the custom TextField, ensure that it functions as expected across different devices and scenarios. Here are some tips:

  • Test with Different Inputs: Verify that the text input and cursor behave correctly with various text lengths and input methods.

  • Accessibility Check: Use tools like TalkBack to ensure your TextField is accessible.

  • Consistency Check: Match the design with other UI elements in your app.

Conclusion

Customizing a TextField in Jetpack Compose can seem challenging at first, but with the right approach, you can create a seamless and visually appealing user experience. By leveraging BasicTextField, controlling the decorationBox, and explicitly setting cursor properties, you can easily remove the underline without compromising functionality.

Jetpack Compose’s flexibility empowers developers to create truly unique and engaging UI components. Start experimenting with these techniques today to elevate your app design to the next level!

If you found this guide helpful, share it with your fellow Android developers and let us know your thoughts in the comments below. For more Jetpack Compose tutorials and tips, stay tuned to our blog!