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Puedes animar, carácter por carácter, la apariencia del texto, de modo que parezca un efecto de escritura en tiempo real, similar al que produciría una máquina de escribir.
Compatibilidad de versiones
Esta implementación requiere que el minSDK de tu proyecto se establezca en el nivel de API 21 o superior.
Dependencias
Anima el texto carácter por carácter
Este código anima el texto carácter por carácter. Hace un seguimiento de un índice para controlar cuánta parte del texto se revela. El texto que se muestra se actualiza de forma dinámica para mostrar únicamente los caracteres hasta el índice actual. Por último, la variable ejecuta la animación cuando cambia.
@ComposableprivatefunAnimatedText(){valtext="This text animates as though it is being typed \uD83E\uDDDE\u200D♀\uFE0F \uD83D\uDD10 \uD83D\uDC69\u200D❤\uFE0F\u200D\uD83D\uDC68 \uD83D\uDC74\uD83C\uDFFD"// Use BreakIterator as it correctly iterates over characters regardless of how they are// stored, for example, some emojis are made up of multiple characters.// You don't want to break up an emoji as it animates, so using BreakIterator will ensure// this is correctly handled!valbreakIterator=remember(text){BreakIterator.getCharacterInstance()}// Define how many milliseconds between each character should pause for. This will create the// illusion of an animation, as we delay the job after each character is iterated on.valtypingDelayInMs=50LvarsubstringTextbyremember{mutableStateOf("")}LaunchedEffect(text){// Initial start delay of the typing animationdelay(1000)breakIterator.text=StringCharacterIterator(text)varnextIndex=breakIterator.next()// Iterate over the string, by index boundarywhile(nextIndex!=BreakIterator.DONE){substringText=text.subSequence(0,nextIndex).toString()// Go to the next logical character boundarynextIndex=breakIterator.next()delay(typingDelayInMs)}}Text(substringText)
BreakIterator itera correctamente sobre los caracteres, independientemente de cómo se almacenen. Por ejemplo, los emojis animados constan de varios caracteres. BreakIterator se asegura de que se manejen como un solo carácter para que la animación no se interrumpa.
LaunchedEffect inicia una corrutina para introducir la demora entre los caracteres. Puedes reemplazar el bloque de código por un objeto de escucha de clics (o cualquier otro evento) para activar la animación.
El elemento componible Text se vuelve a renderizar cada vez que se actualiza el valor de substringText.
Resultados
Figura 1: Texto y emojis animados carácter por carácter.
Colecciones que contienen esta guía
Esta guía forma parte de estas colecciones de guías rápidas seleccionadas que abarcan objetivos más amplios de desarrollo de Android:
Texto visible
El texto es una pieza central de cualquier IU. Descubre las diferentes formas
en que puedes presentar texto en tu app para proporcionar una experiencia del usuario encantadora.
El contenido y las muestras de código que aparecen en esta página están sujetas a las licencias que se describen en la Licencia de Contenido. Java y OpenJDK son marcas registradas de Oracle o sus afiliados.
Última actualización: 2025-02-06 (UTC)
[[["Fácil de comprender","easyToUnderstand","thumb-up"],["Resolvió mi problema","solvedMyProblem","thumb-up"],["Otro","otherUp","thumb-up"]],[["Falta la información que necesito","missingTheInformationINeed","thumb-down"],["Muy complicado o demasiados pasos","tooComplicatedTooManySteps","thumb-down"],["Desactualizado","outOfDate","thumb-down"],["Problema de traducción","translationIssue","thumb-down"],["Problema con las muestras o los códigos","samplesCodeIssue","thumb-down"],["Otro","otherDown","thumb-down"]],["Última actualización: 2025-02-06 (UTC)"],[],[],null,["\u003cbr /\u003e\n\nYou can animate, character-by-character, the appearance of text, so it looks\nlike a streaming typing effect, similar to what a typewriter would produce.\n\nVersion compatibility\n\nThis implementation requires that your project minSDK be set to API level 21 or\nhigher.\n\nDependencies\n\nAnimate text character-by-character\n\nThis code animates text character-by-character. It tracks an index to control\nhow much of the text is revealed. The displayed text updates dynamically to show\nonly the characters up to the current index. Finally, the variable runs the\nanimation when it changes.\n\n\n```kotlin\n@Composable\nprivate fun AnimatedText() {\n val text = \"This text animates as though it is being typed \\uD83E\\uDDDE\\u200D♀\\uFE0F \\uD83D\\uDD10 \\uD83D\\uDC69\\u200D❤\\uFE0F\\u200D\\uD83D\\uDC68 \\uD83D\\uDC74\\uD83C\\uDFFD\"\n\n // Use BreakIterator as it correctly iterates over characters regardless of how they are\n // stored, for example, some emojis are made up of multiple characters.\n // You don't want to break up an emoji as it animates, so using BreakIterator will ensure\n // this is correctly handled!\n val breakIterator = remember(text) { BreakIterator.getCharacterInstance() }\n\n // Define how many milliseconds between each character should pause for. This will create the\n // illusion of an animation, as we delay the job after each character is iterated on.\n val typingDelayInMs = 50L\n\n var substringText by remember {\n mutableStateOf(\"\")\n }\n LaunchedEffect(text) {\n // Initial start delay of the typing animation\n delay(1000)\n breakIterator.text = StringCharacterIterator(text)\n\n var nextIndex = breakIterator.next()\n // Iterate over the string, by index boundary\n while (nextIndex != BreakIterator.DONE) {\n substringText = text.subSequence(0, nextIndex).toString()\n // Go to the next logical character boundary\n nextIndex = breakIterator.next()\n delay(typingDelayInMs)\n }\n }\n Text(substringText)https://github.com/android/snippets/blob/7a0ebbee11495f628cf9d574f6b6069c2867232a/compose/snippets/src/main/java/com/example/compose/snippets/animations/AnimationSnippets.kt#L939-L970\n```\n\n\u003cbr /\u003e\n\nKey points about the code\n\n- [`BreakIterator`](/reference/android/icu/text/BreakIterator) correctly iterates over characters regardless of how they are stored. For example, animated emojis are made up of multiple characters; `BreakIterator` ensures that they're handled as a single character, so that the animation isn't broken.\n- [`LaunchedEffect`](/reference/kotlin/androidx/compose/runtime/package-summary#LaunchedEffect(kotlin.Any,kotlin.coroutines.SuspendFunction1)) starts a coroutine to introduce the delay between the characters. You can replace the code block with a click listener--or any other event--to trigger animation.\n- The [`Text`](/reference/kotlin/androidx/compose/material/package-summary#Text(kotlin.String,androidx.compose.ui.Modifier,androidx.compose.ui.graphics.Color,androidx.compose.ui.unit.TextUnit,androidx.compose.ui.text.font.FontStyle,androidx.compose.ui.text.font.FontWeight,androidx.compose.ui.text.font.FontFamily,androidx.compose.ui.unit.TextUnit,androidx.compose.ui.text.style.TextDecoration,androidx.compose.ui.text.style.TextAlign,androidx.compose.ui.unit.TextUnit,androidx.compose.ui.text.style.TextOverflow,kotlin.Boolean,kotlin.Int,kotlin.Int,kotlin.Function1,androidx.compose.ui.text.TextStyle)) composable re-renders every time the value of `substringText` is updated.\n\nResults\n\n\u003cbr /\u003e\n\n**Figure 1.** Text and emoji animated character-by-character.\n\n\u003cbr /\u003e\n\nCollections that contain this guide\n\nThis guide is part of these curated Quick Guide collections that cover\nbroader Android development goals: \n\nDisplay text \nText is a central piece of any UI. Find out different ways you can present text in your app to provide a delightful user experience. \n[Quick guide collection](/develop/ui/compose/quick-guides/collections/display-text) \n\nCompose basics (video collection) \nThis series of videos introduces various Compose APIs, quickly showing you what's available and how to use them. \n[Quick guide collection](/develop/ui/compose/quick-guides/collections/compose-basics) \n\nHave questions or feedback \nGo to our frequently asked questions page and learn about quick guides or reach out and let us know your thoughts. \n[Go to FAQ](/quick-guides/faq) [Leave feedback](https://issuetracker.google.com/issues/new?component=1573691&template=1993320)"]]