README.md

Crossfade

使用 crossfade 动画来在多个 layout 之间切换, 接收可选的 animationSpec.

CrossfadeExample.kt

import androidx.compose.animation.Crossfade
import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.Column
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.material.Button
import androidx.compose.material.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.Alignment
import androidx.compose.ui.Modifier

@Composable
fun CrossfadeExample() {
  Box(
    modifier = Modifier.fillMaxSize()
  ) {
    Column(
      modifier = Modifier.align(Alignment.Center)
    ) {
      var currentPage by remember { mutableStateOf("A") }

      Button(
        onClick = {
          currentPage = "B"
        }
      ) {
        Text(text = "Change to B")
      }

      Crossfade(
        targetState = currentPage
      ) { screen ->
        when (screen) {
          "A" -> Text("Page A")
          "B" -> Text("Page B")
        }
      }
    }
  }
}