海珠区新闻,网站seo查询站长之家,广告推广策划,东莞市手机网站建设公司【Android Compose】ListView效果 1、Column、Row 和 Box2、LazyColumn和LazyRow3、Compose 中的状态4、ListView效果5、android-compose-codelabs Jetpack Compose 使用入门 Jetpack Compose 教程 Jetpack Compose 1、Column、Row 和 Box Compose 中的三个基本标准布局元素是 … 【Android Compose】ListView效果 1、Column、Row 和 Box2、LazyColumn和LazyRow3、Compose 中的状态4、ListView效果5、android-compose-codelabs Jetpack Compose 使用入门 Jetpack Compose 教程 Jetpack Compose 1、Column、Row 和 Box Compose 中的三个基本标准布局元素是 Column、Row 和 Box 可组合项。 2、LazyColumn和LazyRow androidx.compose.foundation.lazy.LazyColumn androidx.compose.foundation.lazy.LazyRow androidx.compose.foundation.lazy.items 3、Compose 中的状态 7. Compose 中的状态 mutableStateOf 函数该函数可让 Compose 重组读取该 State 的函数如需在重组后保留状态请使用 remember 记住可变状态onClick 它不接受值而接受函数 import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
// ...Composable
fun Greeting(...) {val expanded remember { mutableStateOf(false) }ElevatedButton(onClick { expanded.value !expanded.value },) {Text(if (expanded.value) Show less else Show more)}
}4、ListView效果
https://gitee.com/xhbruce/XhAndroidDemo
package com.xhbruce.xhandroiddemoimport Message
import SampleData
import android.os.Bundle
import androidx.activity.ComponentActivity
import androidx.activity.compose.setContent
import androidx.activity.enableEdgeToEdge
import androidx.compose.animation.animateColorAsState
import androidx.compose.animation.animateContentSize
import androidx.compose.foundation.clickable
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.Spacer
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.foundation.layout.height
import androidx.compose.foundation.layout.padding
import androidx.compose.foundation.lazy.LazyColumn
import androidx.compose.foundation.lazy.items
import androidx.compose.material3.ElevatedButton
import androidx.compose.material3.MaterialTheme
import androidx.compose.material3.Surface
import androidx.compose.material3.Text
import androidx.compose.runtime.Composable
import androidx.compose.runtime.getValue
import androidx.compose.runtime.mutableStateOf
import androidx.compose.runtime.remember
import androidx.compose.runtime.setValue
import androidx.compose.ui.Modifier
import androidx.compose.ui.tooling.preview.Preview
import androidx.compose.ui.unit.dp
import androidx.core.view.WindowCompat
import com.xhbruce.xhandroiddemo.ui.theme.XhAndroidDemoThemeclass MainActivity : ComponentActivity() {override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)enableEdgeToEdge()WindowCompat.setDecorFitsSystemWindows(window, true)setContent {XhAndroidDemoTheme {//PreviewGreeting()Conversation(SampleData.conversationSample)}}}
}Composable
fun MessageCard(msg: Message) {// We keep track if the message is expanded or not in this// variablevar isExpanded by remember { mutableStateOf(false) }// surfaceColor will be updated gradually from one color to the otherval surfaceColor by animateColorAsState(if (isExpanded)MaterialTheme.colorScheme.primaryelseMaterialTheme.colorScheme.surface,)// We toggle the isExpanded variable when we click on this ColumnColumn(modifier Modifier.clickable { isExpanded !isExpanded }.fillMaxSize()) {Text(text msg.author,color MaterialTheme.colorScheme.secondary,style MaterialTheme.typography.titleSmall)Spacer(modifier Modifier.height(4.dp))Surface(shape MaterialTheme.shapes.medium,shadowElevation 1.dp,// surfaceColor color will be changing gradually from primary to surfacecolor surfaceColor,// animateContentSize will change the Surface size graduallymodifier Modifier.animateContentSize().padding(1.dp)) {Text(text msg.body,modifier Modifier.padding(all 4.dp),// If the message is expanded, we display all its content// otherwise we only display the first linemaxLines if (isExpanded) Int.MAX_VALUE else 1,style MaterialTheme.typography.bodyMedium)}}
}Composable
fun Conversation(messages: ListMessage) {LazyColumn {items(messages) { message -MessageCard(message)}}
}Preview
Composable
fun PreviewMessageCard() {XhAndroidDemoTheme {Conversation(SampleData.conversationSample)}
}Preview
Composable
fun PreviewGreeting() {val expanded remember { mutableStateOf(false) }ElevatedButton(onClick { expanded.value !expanded.value },) {Text(if (expanded.value) Show less else Show more)}
}5、android-compose-codelabs
git clone https://github.com/googlecodelabs/android-compose-codelabs.git
