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chrisbanes/Sample.kt Secret

Last active Oct 27, 2020
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What would you like to do?
Compose SystemUI helper
/*
* Copyright 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
class SampleActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContent {
val systemUiController = remember { SystemUiController(window) }
Providers(SystemUiControllerAmbient provides systemUiController) {
MyApp()
}
}
}
}
@Composable
fun MyApp() {
val sysUiController = SystemUiControllerAmbient.current
// This will set the system bars background color (status and navigation bars)
// to be the surface color, and update the foreground to match (light/dark icons).
// If running on a API level where dark foreground isn't available, the background
// color will be transformed to maintain contrast.
sysUiController.setSystemBarsColor(
color = MaterialTheme.colors.surface
)
}
/*
* Copyright 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.example.compose.utils
import android.os.Build
import android.view.View
import android.view.Window
import androidx.compose.staticAmbientOf
import androidx.ui.graphics.Color
import androidx.ui.graphics.compositeOver
import androidx.ui.graphics.luminance
import androidx.ui.graphics.toArgb
/**
* A helper class for setting the navigation and status bar colors for a [Window], gracefully
* degrading behavior based upon API level.
*/
class SystemUiController(private val window: Window) {
/**
* Set the status bar color.
*
* @param color The **desired** [Color] to set. This may require modification if running on an
* API level that only supports white status bar icons.
* @param darkIcons Whether dark status bar icons would be preferable. Only available on
* API 23+.
* @param transformColorForLightContent A lambda which will be invoked to transform [color] if
* dark icons were requested but are not available. Defaults to applying a black scrim.
*/
fun setStatusBarColor(
color: Color,
darkIcons: Boolean = color.luminance() > 0.5f,
transformColorForLightContent: (Color) -> Color = BlackScrimmed
) {
val statusBarColor = when {
darkIcons && Build.VERSION.SDK_INT < 23 -> transformColorForLightContent(color)
else -> color
}
window.statusBarColor = statusBarColor.toArgb()
if (Build.VERSION.SDK_INT >= 23) {
@Suppress("DEPRECATION")
if (darkIcons) {
window.decorView.systemUiVisibility = window.decorView.systemUiVisibility or
View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR
} else {
window.decorView.systemUiVisibility = window.decorView.systemUiVisibility and
View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR.inv()
}
}
}
/**
* Set the navigation bar color.
*
* @param color The **desired** [Color] to set. This may require modification if running on an
* API level that only supports white navigation bar icons. Additionally this will be ignored
* and [Color.Transparent] will be used on API 29+ where gesture navigation is preferred or the
* system UI automatically applies background protection in other navigation modes.
* @param darkIcons Whether dark navigation bar icons would be preferable. Only available on
* API 26+.
* @param transformColorForLightContent A lambda which will be invoked to transform [color] if
* dark icons were requested but are not available. Defaults to applying a black scrim.
*/
fun setNavigationBarColor(
color: Color,
darkIcons: Boolean = color.luminance() > 0.5f,
transformColorForLightContent: (Color) -> Color = BlackScrimmed
) {
val navBarColor = when {
Build.VERSION.SDK_INT >= 29 -> Color.Transparent // For gesture nav
darkIcons && Build.VERSION.SDK_INT < 26 -> transformColorForLightContent(color)
else -> color
}
window.navigationBarColor = navBarColor.toArgb()
if (Build.VERSION.SDK_INT >= 26) {
@Suppress("DEPRECATION")
if (darkIcons) {
window.decorView.systemUiVisibility = window.decorView.systemUiVisibility or
View.SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR
} else {
window.decorView.systemUiVisibility = window.decorView.systemUiVisibility and
View.SYSTEM_UI_FLAG_LIGHT_NAVIGATION_BAR.inv()
}
}
}
/**
* Set the status and navigation bars to [color].
*
* @see setStatusBarColor
* @see setNavigationBarColor
*/
fun setSystemBarsColor(
color: Color,
darkIcons: Boolean = color.luminance() > 0.5f,
transformColorForLightContent: (Color) -> Color = BlackScrimmed
) {
setStatusBarColor(color, darkIcons, transformColorForLightContent)
setNavigationBarColor(color, darkIcons, transformColorForLightContent)
}
}
/**
* An [androidx.compose.Ambient] holding the current [SystemUiController] or throws an error if none
* is [provided][androidx.compose.Providers].
*/
val SystemUiControllerAmbient = staticAmbientOf<SystemUiController> {
error("No SystemUiController provided")
}
private val BlackScrim = Color(0f, 0f, 0f, 0.2f) // 20% opaque black
private val BlackScrimmed: (Color) -> Color = { original ->
BlackScrim.compositeOver(original)
}
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