留言板实现跑马灯效果

app/build.gradle.kts

@@ -129,8 +129,6 @@ dependencies {
     kapt("androidx.room:room-compiler:${rootProject.extra["room_version"]}")
     // optional - Kotlin Extensions and Coroutines support for Room
     implementation("androidx.room:room-ktx:${rootProject.extra["room_version"]}")
-    //
-    implementation("androidx.constraintlayout:constraintlayout-compose:1.0.0-alpha03")
     // optional - Test helpers
     testImplementation("androidx.room:room-testing:${rootProject.extra["room_version"]}")
     //测试

app/src/main/java/com/gyf/csams/ui/Base.kt

@@ -17,6 +17,7 @@ import androidx.navigation.NavController
 import androidx.navigation.compose.navigate
 import androidx.navigation.compose.rememberNavController
 import com.gyf.csams.R
+import com.gyf.csams.ui.theme.CSAMSTheme
 
 /**
  * 淡入淡出并且颜色变化文本
@@ -71,7 +72,7 @@ fun MenuIconButton(_menu: MainMenu,menu: MainMenu,modifier: Modifier,onClick: ()
 
 @Composable
 fun MyBottomAppBar(menu:MainMenu,nav: NavController,modifier: Modifier=Modifier){
-    BottomAppBar(backgroundColor = Color.Transparent,modifier=modifier) {
+    BottomAppBar(backgroundColor = Color.White,modifier=modifier) {
         //图标宽度平等分
 
         val weight=1/(MainMenu.values().size*1.0f)
@@ -98,5 +99,9 @@ fun AnimationTextPreview(){
 @Composable
 fun MyBottomAppBarPreview(){
     val nav= rememberNavController()
+    CSAMSTheme {
+        Surface(color = MaterialTheme.colors.background) {
             MyBottomAppBar(menu = MainMenu.Main, nav = nav)
         }
+    }
+}

app/src/main/java/com/gyf/csams/ui/MainActivity.kt

@@ -3,13 +3,16 @@ package com.gyf.csams.ui
 import android.os.Bundle
 import androidx.activity.ComponentActivity
 import androidx.activity.compose.setContent
+import androidx.compose.animation.core.*
 import androidx.compose.foundation.Image
-import androidx.compose.foundation.background
 import androidx.compose.foundation.border
 import androidx.compose.foundation.layout.*
 import androidx.compose.foundation.shape.RoundedCornerShape
 import androidx.compose.material.*
 import androidx.compose.runtime.Composable
+import androidx.compose.runtime.State
+import androidx.compose.runtime.getValue
+import androidx.compose.runtime.livedata.observeAsState
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.rotate
@@ -18,13 +21,15 @@ import androidx.compose.ui.res.painterResource
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.tooling.preview.Preview
 import androidx.compose.ui.unit.dp
-import androidx.constraintlayout.compose.ConstraintLayout
+import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
 import androidx.navigation.compose.rememberNavController
 import com.gyf.csams.R
+import com.gyf.csams.ui.model.MainViewModel
 import com.gyf.csams.ui.theme.CSAMSTheme
 
+
 /**
  * 主界面
  *
@@ -68,11 +73,13 @@ fun Body(){
                     Box(modifier = Modifier.fillMaxSize()) {
                         Column(Modifier.rotate(180F)) {
                             MyBottomAppBar(MainMenu.List, navController, Modifier.rotate(180F))
-                            Row(modifier = Modifier
+                            Row(
+                                modifier = Modifier
                                     .fillMaxSize()
                                     .rotate(180F),
                                 horizontalArrangement = Arrangement.Center,
-                                verticalAlignment = Alignment.CenterVertically) {
+                                verticalAlignment = Alignment.CenterVertically
+                            ) {
                                 AnimationText(text = "社团列表")
                             }
                         }
@@ -82,11 +89,13 @@ fun Body(){
                     Box(modifier = Modifier.fillMaxSize()) {
                         Column(Modifier.rotate(180F)) {
                             MyBottomAppBar(MainMenu.Center, navController, Modifier.rotate(180F))
-                            Row(modifier = Modifier
+                            Row(
+                                modifier = Modifier
                                     .fillMaxSize()
                                     .rotate(180F),
                                 horizontalArrangement = Arrangement.Center,
-                                verticalAlignment = Alignment.CenterVertically) {
+                                verticalAlignment = Alignment.CenterVertically
+                            ) {
                                 AnimationText(text = "个人中心")
                             }
                         }
@@ -104,13 +113,17 @@ fun Body(){
  */
 @Composable
 fun Notification() {
-    Row(horizontalArrangement = Arrangement.End,
+    Row(
+        horizontalArrangement = Arrangement.End,
         modifier = Modifier
             .fillMaxWidth()
-            .padding(10.dp)) {
-        Icon(painter = painterResource(id = R.drawable.ic_notification),
+            .padding(10.dp)
+    ) {
+        Icon(
+            painter = painterResource(id = R.drawable.ic_notification),
             contentDescription = null,
-            modifier = Modifier.size(50.dp))
+            modifier = Modifier.size(50.dp)
+        )
     }
 }
 
@@ -123,7 +136,11 @@ fun MyBorder(content: @Composable BoxScope.() -> Unit){
     Box(modifier = Modifier.padding(horizontal = 15.dp)) {
         Box(
             modifier = Modifier
-                .border(width = 1.dp, color = Color.Black, shape = RoundedCornerShape(size = 20.dp)),
+                .border(
+                    width = 1.dp,
+                    color = Color.Black,
+                    shape = RoundedCornerShape(size = 20.dp)
+                ),
         ) {
             content()
         }
@@ -135,25 +152,27 @@ fun MyBorder(content: @Composable BoxScope.() -> Unit){
  *
  */
 @Composable
-fun MessageBoard() {
+fun MessageBoard(model: MainViewModel= viewModel()) {
     MyBorder {
-        Row(modifier = Modifier.rotate(180F),
-            verticalAlignment = Alignment.CenterVertically) {
+        Row(
+            verticalAlignment = Alignment.CenterVertically
+        ) {
 
             Icon(
                 painter = painterResource(id = R.drawable.ic_comments),
                 contentDescription = null,
                 modifier = Modifier
                     .size(50.dp)
-                    .rotate(180F)
             )
             Row(
                 horizontalArrangement = Arrangement.Center,
                 modifier = Modifier
                     .fillMaxWidth()
-                    .rotate(180F)
             ) {
-                Text(text = "跑马灯留言")
+                Marquee(model = model) {
+                        model, value -> TestA(model = model,
+                    offset = value)
+                }
             }
 
         }
@@ -174,10 +193,12 @@ fun ClubActivitiesTitle(){
             horizontalArrangement = Arrangement.Center,
             verticalAlignment = Alignment.CenterVertically
         ) {
-            Text(text = "超级课程表X滴滴出行-了不起的社团",
+            Text(
+                text = "超级课程表X滴滴出行-了不起的社团",
                 style = MaterialTheme.typography.h6,
                 overflow = TextOverflow.Ellipsis,
-                maxLines = 1)
+                maxLines = 1
+            )
         }
     }
 }
@@ -189,58 +210,120 @@ fun ClubActivitiesTitle(){
 @Composable
 fun ClubActivitiesImage() {
     Column(modifier = Modifier.fillMaxSize()) {
-            Card(modifier = Modifier
-                .weight(0.4f)
-                .fillMaxWidth()) {
-                Image(painter = painterResource(id = R.drawable.hot_activity_desc_background),
-                    contentDescription = null)
-                Box(modifier = Modifier
+        Card(
+            modifier = Modifier
+                .weight(0.4F)
+                .fillMaxWidth()
+        ) {
+            Image(
+                painter = painterResource(id = R.drawable.hot_activity_desc_background),
+                contentDescription = null
+            )
+            Box(
+                modifier = Modifier
                     .padding(horizontal = 85.dp, vertical = 30.dp)
-                    .rotate(180F)){
-                    Text(text = "文字对任何界面都属于核心内容，而利用 Jetpack Compose 可以更轻松地显示或写入文字。Compose 可以充分利用其构建块的组合，这意味着您无需覆盖各种属性和方法，也无需扩展大型类，即可拥有特定的可组合项设计以及按您期望的方式运行的逻辑。"
-                        .repeat(10),overflow = TextOverflow.Ellipsis)
+                    .rotate(180F)
+            ) {
+                Text(
+                    text = "文字对任何界面都属于核心内容，而利用 Jetpack Compose 可以更轻松地显示或写入文字。Compose 可以充分利用其构建块的组合，这意味着您无需覆盖各种属性和方法，也无需扩展大型类，即可拥有特定的可组合项设计以及按您期望的方式运行的逻辑。"
+                        .repeat(10), overflow = TextOverflow.Ellipsis
+                )
             }
 
         }
-        Card(modifier = Modifier
-            .weight(0.6f)
-            .fillMaxWidth()) {
-            Image(painter = painterResource(id = R.drawable.hot_activity_background),
-                contentDescription = null)
-            Image(painter = painterResource(id = R.drawable.ic_launcher_foreground),
-                contentDescription = null)
+        Card(
+            modifier = Modifier
+                .weight(0.6F)
+                .fillMaxWidth()
+        ) {
+            Image(
+                painter = painterResource(id = R.drawable.hot_activity_background),
+                contentDescription = null
+            )
+            Image(
+                painter = painterResource(id = R.drawable.ic_launcher_foreground),
+                contentDescription = null
+            )
 
         }
     }
 }
 
-//@Preview(showBackground = true)
+
+@Preview(showBackground = true)
 @Composable
 fun DefaultPreview() {
+    val model = MainViewModel()
     CSAMSTheme {
         Box(modifier = Modifier.fillMaxSize()) {
             Column {
-                ClubActivitiesImage()
+//                Marquee(model = model) {
+//                        model, value -> TestA(model = model,
+//                                            offset = value)
+//                }
+                MessageBoard(model = model)
             }
         }
     }
 }
 
-@Preview
+
+
+
 @Composable
-fun ConstraintLayoutContent() {
-    Box(modifier = Modifier.background(Color.Cyan)) {
-        ConstraintLayout {
-            // Create references for the composables to constrain
-            val (button, text,text2,box) = createRefs()
+fun TestA(model: MainViewModel= viewModel(),offset:State<Float>){
+    val poetryIndex: Int by model.poetryIndex.observeAsState(0)
 
-            Box(Modifier.fillMaxSize())
+//        Text(text = "$poetryIndex")
+//        Text(text = "offset.value=${offset.value}")
+        Text(
+            text = model.poetry[poetryIndex % model.poetry.size],
+            modifier = Modifier.offset(x = offset.value.dp),
+            maxLines = 1,
+            overflow = TextOverflow.Ellipsis
+        )
 
-            Box(Modifier.size(50.dp).background(Color.Red).constrainAs(box){
-                bottom.linkTo(parent.bottom)
+}
 
-                end.linkTo(parent.end)
-            })
+/**
+ * 轮播
+ *
+ */
+@Composable
+fun Carousel(){
+
+}
+
+/**
+ * 跑马灯
+ *
+ * @param model
+ * @param content
+ */
+@Composable
+fun Marquee(model: MainViewModel= viewModel(),content: @Composable BoxScope.(model:MainViewModel,
+                                                                             value:State<Float>) -> Unit) {
+
+    val delayMillis=2000
+    Column {
+        BoxWithConstraints {
+            val transition = rememberInfiniteTransition()
+            val maxWidth = maxWidth + 30.dp
+            val offset = transition.animateFloat(
+                initialValue = 0F,
+                targetValue = maxWidth.value,
+                animationSpec = infiniteRepeatable(
+                    animation = tween(durationMillis = 3000,delayMillis = delayMillis),
+                    repeatMode = RepeatMode.Restart
+                )
+            )
+                Box(modifier = Modifier.fillMaxWidth()) {
+                    content(model=model,value=offset)
+                }
+
+                if (offset.value.toInt() == maxWidth.value.toInt()) {
+                    model.addAsync(delayMillis = delayMillis)
+                }
         }
     }
 }

app/src/main/java/com/gyf/csams/ui/model/MainViewModel.kt

@@ -0,0 +1,33 @@
+package com.gyf.csams.ui.model
+
+import androidx.lifecycle.LiveData
+import androidx.lifecycle.MutableLiveData
+import androidx.lifecycle.ViewModel
+import androidx.lifecycle.viewModelScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.delay
+import kotlinx.coroutines.launch
+
+
+class MainViewModel:ViewModel() {
+    val poetry= listOf("床前明月光","疑是地上霜","举头望明月","低头思故乡")
+
+    private val _poetryIndex=MutableLiveData(0)
+    var poetryIndex:LiveData<Int> = _poetryIndex
+    var job:Job? = null
+
+
+    fun addAsync(delayMillis:Int){
+        if(job == null || job?.isCompleted==true) {
+            job = viewModelScope.launch {
+                _poetryIndex.postValue(
+                    if (_poetryIndex.value == poetry.size-1) 0 else _poetryIndex.value?.plus(
+                        1
+                    )
+                )
+                delay(timeMillis = delayMillis.toLong())
+            }
+        }
+
+    }
+}