Android 开发中我们普遍使用今日头条的适配框架。
今日头条方案:
基于系统将 dp 转换为 px 的公式
px = dp * density
来实现适配,通过在运行时动态修改 density 值的大小,使得修改后计算出的屏幕宽度就等于设计稿的宽度,从而使得在不同屏幕尺寸下我们都可以直接使用设计稿给出的 dp 值,且无需准备多套 dimens 文件。
所以Jetpack Compose中我们也可以参考这种方式做适配。
假如屏幕 长是817dp,应用只显示为横屏。
val displayMetrics = LocalContext.current.resources.displayMetrics
val fontScale = LocalDensity.current.fontScale
val widthPixels = displayMetrics.widthPixels
val widthDensity = widthPixels / 817.0f
CompositionLocalProvider(
LocalDensity provides Density(
density = widthDensity,
fontScale = fontScale
)
) {
ContentView(appViewModel, coroutineScope, pagerState)
}
只需在我们需要适配的最外层组件设置,所有的内层组件都会生效。
假如屏幕 长是817dp,宽度510dp
val configuration = LocalConfiguration.current
val isLandscape = configuration.orientation == Configuration.ORIENTATION_LANDSCAPE
val widthDp = if (isLandscape) 817.0f else 510.0f
上面的就可以改为
val displayMetrics = LocalContext.current.resources.displayMetrics
val fontScale = LocalDensity.current.fontScale
val widthPixels = displayMetrics.widthPixels
val configuration = LocalConfiguration.current
val isLandscape = configuration.orientation == Configuration.ORIENTATION_LANDSCAPE
val widthDp = if (isLandscape) 817.0f else 510.0f
val widthDensity = widthPixels / widthDp
CompositionLocalProvider(
LocalDensity provides Density(
density = widthDensity,
fontScale = fontScale
)
) {
ContentView(appViewModel, coroutineScope, pagerState)
}
其中:
widthPixels
会自动根据屏幕的横竖方向获取对应的宽度,不用我们判断。
我们也可以抽取到 MaterialTheme 中,使其默认生效,进一步减少代码量。
把原来的
MaterialTheme(
colorScheme = colorScheme,
typography = Typography,
content = content
)
改为
val displayMetrics = LocalContext.current.resources.displayMetrics
val fontScale = LocalDensity.current.fontScale
val widthPixels = displayMetrics.widthPixels
val configuration = LocalConfiguration.current
val isLandscape = configuration.orientation == Configuration.ORIENTATION_LANDSCAPE
val widthDp = if (isLandscape) 817.0f else 510.0f
val widthDensity = widthPixels / widthDp
MaterialTheme(
colorScheme = colorScheme,
typography = Typography,
content = {
CompositionLocalProvider(
LocalDensity provides Density(
density = widthDensity,
fontScale = fontScale
)
) {
content()
}
}
)