Jetpack Compose Text的基本使用
作者：toskyline
这篇文章主要介绍了Jetpack Compose Text的基本使用，文章围绕主题展开详细的内容介绍，具有一定的参考价值，需要的小伙伴可以参考一下
Text
文字是任何界面必须的元素，Compose Text 可组合项，通过设置文字、大小、颜色可以实现各种文字效果。
Text的基本用法如下：
@Composable
fun Text(
//要显示的文字
text: String,
//修饰符
modifier: Modifier = Modifier,
//文字颜色
color: Color = Color.Unspecified,
//文字大小
fontSize: TextUnit = TextUnit.Unspecified,
//文字样式,正常或者斜体
fontStyle: FontStyle? = null,
//字重，范围：1~1000之间
fontWeight: FontWeight? = null,
//字体
fontFamily: FontFamily? = null,
//字幕之间间距
letterSpacing: TextUnit = TextUnit.Unspecified,
//文字装饰，下划线、中划线或者None
textDecoration: TextDecoration? = null,
//文字对齐方式
textAlign: TextAlign? = null,
//行高
lineHeight: TextUnit = TextUnit.Unspecified,
//溢出处理方式，裁剪、省略号或者正常显示
overflow: TextOverflow = TextOverflow.Clip,
//是否处理换行符
softWrap: Boolean = true,
//最大行数
maxLines: Int = Int.MAX_VALUE,
//计算文本布局时的回调
onTextLayout: (TextLayoutResult) -> Unit = {},
//文本样式,颜色、字体等
style: TextStyle = LocalTextStyle.current
)基本使用
@Composable
fun TextCommon() {
Text(
"Hello World",
color = Color.Blue,
fontSize = 30.sp,
fontWeight = FontWeight.Bold,
textAlign = TextAlign.Center,
modifier = Modifier
.width(150.dp)
.background(Color(0xff44D1FD)),
fontFamily = FontFamily.SansSerif,
fontStyle = FontStyle.Italic,
textDecoration = TextDecoration.LineThrough,
style = TextStyle.Default
)
}通过简单设置字体、颜色、文字大小 等就能满足我们的基本要求。
效果如下：
富文本显示
如果需要显示不同的文字样式，就必须用到 AnnotatedString，通过 buildAnnotatedString()可以实现各种富文本的显示。
@Composable
fun RichText() {
Text(
buildAnnotatedString {
withStyle(style = SpanStyle(color = Color.Blue)) {
append("H")
}
append("ello ")
withStyle(style = SpanStyle(fontWeight = FontWeight.Bold, color = Color.Red)) {
append("W")
}
append("orld")
withStyle(style = ParagraphStyle(lineHeight = 30.sp)) {
withStyle(style = SpanStyle(color = Color.Blue)) {
append("Hello\n")
}
withStyle(
style = SpanStyle(
fontWeight = FontWeight.Bold,
color = Color.Red
)
) {
append("World\n")
}
append("Compose")
}
}, modifier = Modifier.padding(start = 10.dp).background(Color(0xff44D1FD))
)
}通过buildAnnotatedString() + withStyle() 设置不同位置的，显示不同效果。
效果如下：
文字部分可选
@Composable
fun PartiallySelectableText() {
SelectionContainer {
Column(modifier = Modifier.padding(start = 10.dp).background(Color(0xff44D1FD))) {
Text("This text is selectable")
Text("This one too")
Text("This one as well")
DisableSelection {
Text("But not this one")
Text("Neither this one")
}
Text("But again, you can select this one")
Text("And this one too")
}
}
}默认情况下，Compose可组合项不可以选择，要启用选择，需要使用SelectionContainer包裹文字组合。你也可以选择在部分区域禁止选择，DisableSelection包裹文字部分就可以实现部分不可选。效果如下：
可点击文字
@Composable
fun AnnotatedClickableText() {
val context = LocalContext.current
val annotatedText = buildAnnotatedString {
append("Click ")
pushStringAnnotation(tag = "URL", annotation = "https://developer.android.com")
withStyle(style = SpanStyle(color = Color.Blue, fontWeight = FontWeight.Bold)) {
append("here")
}
pop()
}
ClickableText(
modifier = Modifier.padding(start = 10.dp).background(Color(0xff44D1FD)),
text = annotatedText,
onClick = { offset ->
annotatedText.getStringAnnotations(tag = "URL", start = offset, end = offset)
.firstOrNull()?.let { annotation ->
// If yes, we log its value
Log.d("Clicked URL", annotation.item)
val uri = Uri.parse(annotation.item)
val intent = Intent(Intent.ACTION_VIEW, uri)
context.startActivity(intent)
}
}
)
}通过pushStringAnnotation() 设置tag,然后在ClickableText 的onClick 回调处理点击事件。效果如下：
TextField
TextField 允许用户输入文字，TextField 是 BasicTextField 的简单封装，包含了各种装饰。
@Composable
fun SimpleFilledTextField() {
var text by remember { mutableStateOf("Hello") }
TextField(
value = text,
onValueChange = { text = it },
label = { Text("Label") },
placeholder = { Text("placeholder") },
leadingIcon = { Text("leadingIcon") },
trailingIcon = { Text("trailingIcon") },
isError = true,
modifier = Modifier
.padding(start = 10.dp, end = 10.dp)
.fillMaxWidth(),
maxLines = 10,
singleLine = false,
keyboardActions = KeyboardActions(
onDone = {
},
onNext = {
},
onPrevious = {
},
onSearch = {
},
onSend = {
},
onGo = {
}
),
keyboardOptions = KeyboardOptions(
capitalization = KeyboardCapitalization.Characters,
autoCorrect = true,
keyboardType = KeyboardType.Number,
imeAction = ImeAction.Search
),
readOnly = false
)
}
BasicTextField
@Composable
fun Search() {
var key by remember {
mutableStateOf("")
}
Box(modifier = Modifier.padding(end = 35.dp)) {
Row(
modifier = Modifier
.padding(top = 10.dp, bottom = 10.dp)
.fillMaxSize()
.clip(CircleShape)
.background(Color.White),
verticalAlignment = Alignment.CenterVertically
) {
Icon(
painter = painterResource(id = com.zjp.common.R.drawable.search),
contentDescription = "search", tint = Color.Gray,
modifier = Modifier.padding(start = 10.dp)
)
BasicTextField(
value = key,
onValueChange = {
key = it
},
modifier = Modifier
.fillMaxWidth()
.padding(start = 10.dp, end = 30.dp)
.align(Alignment.CenterVertically),
textStyle = TextStyle(
textAlign = TextAlign.Justify,
fontSize = 20.sp,
color = Color.Black.copy(alpha = 0.8f)
),
singleLine = true,
cursorBrush = SolidColor(Color.Red),
keyboardActions = KeyboardActions(
onSearch = {
}
),
keyboardOptions = KeyboardOptions(
imeAction = ImeAction.Search
),
decorationBox = { innerTextField ->
Box() {
if (key.isEmpty()) {
Text("搜点啥", color = Color.Gray, fontSize = 20.sp)
}
innerTextField() //<-- Add this
}
}
)
}
if (key.isNotEmpty()) {
Icon(
painter = painterResource(id = android.R.drawable.ic_menu_close_clear_cancel),
contentDescription = "close",
modifier = Modifier
.align(Alignment.CenterEnd)
.padding(end = 10.dp)
.clickable { key = "" },
tint = Color.Gray
)
}
}
}与TextField 相比，BasicTextField 没有 leadingIcon、placeholder、trailingIcon 等装饰，你可以通过配合其他科组合项，实现不同的效果。
简单搜索框效果如下：
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