Adds Compose buttons.

Includes logic to add them to the Compose Gallery app.

There's probably a lot of work that still needs to go into Buttons.kt
but this is a start.

Bug: 246002087
Test: Compose gallery app screen for buttons
Change-Id: If284f43c205b04009b63d5eab2cc53f3b334e515

packages/SystemUI/compose/core/src/com/android/systemui/compose/SystemUiButtons.kt

@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2022 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.android.systemui.compose
+
+import androidx.compose.foundation.BorderStroke
+import androidx.compose.foundation.layout.PaddingValues
+import androidx.compose.foundation.layout.RowScope
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.ButtonColors
+import androidx.compose.material3.ButtonDefaults
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.unit.dp
+import com.android.systemui.compose.theme.LocalAndroidColorScheme
+
+@Composable
+fun SysUiButton(
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+    enabled: Boolean = true,
+    content: @Composable RowScope.() -> Unit,
+) {
+    androidx.compose.material3.Button(
+        modifier = modifier.padding(vertical = 6.dp).height(36.dp),
+        colors = filledButtonColors(),
+        contentPadding = ButtonPaddings,
+        onClick = onClick,
+        enabled = enabled,
+    ) {
+        content()
+    }
+}
+
+@Composable
+fun SysUiOutlinedButton(
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+    enabled: Boolean = true,
+    content: @Composable RowScope.() -> Unit,
+) {
+    androidx.compose.material3.OutlinedButton(
+        modifier = modifier.padding(vertical = 6.dp).height(36.dp),
+        enabled = enabled,
+        colors = outlineButtonColors(),
+        border = outlineButtonBorder(),
+        contentPadding = ButtonPaddings,
+        onClick = onClick,
+    ) {
+        content()
+    }
+}
+
+@Composable
+fun SysUiTextButton(
+    onClick: () -> Unit,
+    modifier: Modifier = Modifier,
+    enabled: Boolean = true,
+    content: @Composable RowScope.() -> Unit,
+) {
+    androidx.compose.material3.TextButton(
+        onClick = onClick,
+        modifier = modifier,
+        enabled = enabled,
+        content = content,
+    )
+}
+
+private val ButtonPaddings = PaddingValues(horizontal = 16.dp, vertical = 8.dp)
+
+@Composable
+private fun filledButtonColors(): ButtonColors {
+    val colors = LocalAndroidColorScheme.current
+    return ButtonDefaults.buttonColors(
+        containerColor = colors.colorAccentPrimary,
+        contentColor = colors.textColorOnAccent,
+    )
+}
+
+@Composable
+private fun outlineButtonColors(): ButtonColors {
+    val colors = LocalAndroidColorScheme.current
+    return ButtonDefaults.outlinedButtonColors(
+        contentColor = colors.textColorPrimary,
+    )
+}
+
+@Composable
+private fun outlineButtonBorder(): BorderStroke {
+    val colors = LocalAndroidColorScheme.current
+    return BorderStroke(
+        width = 1.dp,
+        color = colors.colorAccentPrimaryVariant,
+    )
+}

packages/SystemUI/compose/gallery/src/com/android/systemui/compose/gallery/ButtonsScreen.kt

@@ -0,0 +1,77 @@
+/*
+ * Copyright (C) 2022 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.
+ *
+ */
+
+@file:OptIn(ExperimentalMaterial3Api::class)
+
+package com.android.systemui.compose.gallery
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.material3.ExperimentalMaterial3Api
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import com.android.systemui.compose.SysUiButton
+import com.android.systemui.compose.SysUiOutlinedButton
+import com.android.systemui.compose.SysUiTextButton
+
+@Composable
+fun ButtonsScreen(
+    modifier: Modifier = Modifier,
+) {
+    Column(
+        modifier = modifier,
+    ) {
+        SysUiButton(
+            onClick = {},
+        ) {
+            Text("SysUiButton")
+        }
+
+        SysUiButton(
+            onClick = {},
+            enabled = false,
+        ) {
+            Text("SysUiButton - disabled")
+        }
+
+        SysUiOutlinedButton(
+            onClick = {},
+        ) {
+            Text("SysUiOutlinedButton")
+        }
+
+        SysUiOutlinedButton(
+            onClick = {},
+            enabled = false,
+        ) {
+            Text("SysUiOutlinedButton - disabled")
+        }
+
+        SysUiTextButton(
+            onClick = {},
+        ) {
+            Text("SysUiTextButton")
+        }
+
+        SysUiTextButton(
+            onClick = {},
+            enabled = false,
+        ) {
+            Text("SysUiTextButton - disabled")
+        }
+    }
+}

packages/SystemUI/compose/gallery/src/com/android/systemui/compose/gallery/GalleryApp.kt

@@ -31,6 +31,7 @@ object GalleryAppScreens {
     val Typography = ChildScreen("typography") { TypographyScreen() }
     val MaterialColors = ChildScreen("material_colors") { MaterialColorsScreen() }
     val AndroidColors = ChildScreen("android_colors") { AndroidColorsScreen() }
+    val Buttons = ChildScreen("buttons") { ButtonsScreen() }
     val ExampleFeature = ChildScreen("example_feature") { ExampleFeatureScreen() }
 
     val PeopleEmpty =
@@ -63,6 +64,7 @@ object GalleryAppScreens {
                 "Material colors" to MaterialColors,
                 "Android colors" to AndroidColors,
                 "Example feature" to ExampleFeature,
+                "Buttons" to Buttons,
                 "People" to People,
             )
         )