pxt-calliope/olddocs/lessons/screen-wipe/activity.md

screen wipe blocks activity

Clear the screen by pressing buttons on the micro:bit

~avatar avatar

This activity will teach how to clear the screen by pressing button A on the micro:bit.

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You can use the clear screen` function to turn off all the LED on the screen. Let's illustrate this concept with a small script where the user has to press the button A to turn off the screen. Let's start by adding the code to show an animation.

basic.showLeds(`
    # # # # #
    # # # # #
    . . . . .
    . . . . .
    . . . . .
    `)
basic.showLeds(`
    # # # # #
    # # # # #
    # # # # #
    # # # # #
    . . . . .
    `)
basic.showLeds(`
    . . . . .
    . . . . .
    # # # # #
    # # # # #
    . . . . .
    `)
basic.showLeds(`
    . . . . .
    . . . . .
    . . . . .
    # # # # #
    # # # # #
    `)

We add another line of code that registers an event handler on button pressed A and calls clear screen.

basic.showLeds(`
    # # # # #
    # # # # #
    . . . . .
    . . . . .
    . . . . .
    `)
basic.showLeds(`
    # # # # #
    # # # # #
    # # # # #
    # # # # #
    . . . . .
    `)
basic.showLeds(`
    . . . . .
    . . . . .
    # # # # #
    # # # # #
    . . . . .
    `)
basic.showLeds(`
    . . . . .
    . . . . .
    . . . . .
    # # # # #
    # # # # #
    `)
input.onButtonPressed(Button.A, () => {
    basic.clearScreen()
})

Run the script in the simulator or on the micro:bit to see how this works!

~avatar boothing

Excellent, you're ready to continue with the challenges!

~