Variable expression concept

demoProjects/Var/.gitignore

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+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties

demoProjects/Var/app/.gitignore

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+/build

demoProjects/Var/app/build.gradle

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+plugins {
+    id 'com.android.application'
+    id 'org.jetbrains.kotlin.android'
+}
+
+android {
+    namespace 'androidx.demo.var'
+    compileSdk 32
+
+    defaultConfig {
+        applicationId "androidx.demo.var"
+        minSdk 21
+        targetSdk 32
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+        vectorDrawables {
+            useSupportLibrary true
+        }
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+    buildFeatures {
+        compose true
+    }
+    composeOptions {
+        kotlinCompilerExtensionVersion '1.1.1'
+    }
+    packagingOptions {
+        resources {
+            excludes += '/META-INF/{AL2.0,LGPL2.1}'
+        }
+    }
+}
+
+dependencies {
+    implementation 'androidx.constraintlayout:constraintlayout-compose:1.1.0-alpha03'
+    implementation 'androidx.core:core-ktx:1.7.0'
+    implementation 'androidx.activity:activity-compose:1.3.1'
+    implementation "androidx.compose.ui:ui:$compose_ui_version"
+    implementation "androidx.compose.ui:ui-tooling-preview:$compose_ui_version"
+    implementation 'androidx.compose.material:material:1.1.1'
+    implementation project(path: ':lua')
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
+    androidTestImplementation "androidx.compose.ui:ui-test-junit4:$compose_ui_version"
+    debugImplementation "androidx.compose.ui:ui-tooling:$compose_ui_version"
+    debugImplementation "androidx.compose.ui:ui-test-manifest:$compose_ui_version"
+}

demoProjects/Var/app/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

demoProjects/Var/app/src/androidTest/java/androidx/demo/var/ExampleInstrumentedTest.kt

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+package androidx.demo.`var`
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("androidx.demo.var", appContext.packageName)
+    }
+}

demoProjects/Var/app/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools">
+
+    <application
+        android:allowBackup="true"
+        android:dataExtractionRules="@xml/data_extraction_rules"
+        android:fullBackupContent="@xml/backup_rules"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.Var"
+        tools:targetApi="31">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:label="@string/app_name"
+            android:theme="@style/Theme.Var">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>

demoProjects/Var/app/src/main/java/androidx/demo/var/MainActivity.kt

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+package androidx.demo.`var`
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.fillMaxSize
+import androidx.compose.material.MaterialTheme
+import androidx.compose.material.Surface
+import androidx.compose.material.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.graphics.Color
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.constraintlayout.compose.ExperimentalMotionApi
+import androidx.constraintlayout.compose.MotionLayout
+import androidx.constraintlayout.compose.MotionLayoutDebugFlags
+import androidx.constraintlayout.compose.MotionScene
+import androidx.constraintlayout.compose.layoutId
+import androidx.demo.`var`.ui.theme.VarTheme
+import androidx.demo.lua.ExpressionEngine
+import java.util.*
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            VarTheme {
+                // A surface container using the 'background' color from the theme
+                Surface(
+                    modifier = Modifier.fillMaxSize(),
+                    color = MaterialTheme.colors.background
+                ) {
+                    DefaultPreview( )
+                }
+            }
+        }
+    }
+}
+
+
+@OptIn(ExperimentalMotionApi::class)
+@Preview(showBackground = true)
+@Composable
+fun DefaultPreview() {
+
+    var scene =
+        """
+       {
+       vars: {
+             mWidth: '50',
+             mHeight: 'mWidth * 9 /16'
+       },
+         ConstraintSets: {
+           start: {
+             box1: {
+               width: '#mWidth', height:  '#mHeight',
+               bottom: ['parent', 'bottom', 10],
+               start: ['parent', 'start', 10],
+             },
+               title: {
+                   top: ['parent', 'top', 10],
+               start: ['parent', 'start', 10],
+                end: ['parent', 'end', 10],
+             },
+               box2: {
+               width: 50, height: 50,
+               bottom: ['parent', 'bottom', 10],
+               start: ['parent', 'start', 10],
+               motion: {
+                  pathArc : 'startHorizontal'
+               }
+             }
+           },
+           end: {
+               box1: {
+                       width: 50, height: 50,
+                       top: ['parent', 'top', 10],
+                       end: ['parent', 'end', 10],
+                    },
+              title: {
+                 top: ['parent', 'top', 10],
+               start: ['parent', 'start', 10],
+                end: ['parent', 'end', 10],
+             },
+             box2: {
+                width: 50, height: 50,
+                top: ['parent', 'top', 40],
+                end: ['parent', 'end', 10],
+             }
+           }
+         },
+         Transitions: {
+           default: {
+              from: 'start',
+              to: 'end',
+               pathMotionArc : 'none',
+              onSwipe: {
+                anchor: 'box1',
+                maxVelocity: 4.2,
+                maxAccel: 3,
+                direction: 'end',
+                side: 'start',
+                mode: 'velocity'
+              }
+           }
+         }
+       }
+        """.trimIndent()
+    var exp = ExpressionEngine()
+    scene = exp.process(scene)
+    Column {
+        MotionLayout(
+            modifier = Modifier
+                .fillMaxSize()
+                .background(Color.LightGray),
+            motionScene = MotionScene(content = scene),
+            debug= EnumSet.of(MotionLayoutDebugFlags.SHOW_ALL),
+        ) {
+            Text(text = "pathArc motion attributes",
+                modifier = Modifier.layoutId("title"))
+            Box(
+                modifier = Modifier
+                    .background(Color.Red)
+                    .layoutId("box1")
+            )
+            Box(
+                modifier = Modifier
+                    .background(Color.Green)
+                    .layoutId("box2")
+            )
+        }
+    }
+}

demoProjects/Var/app/src/main/java/androidx/demo/var/ui/theme/Color.kt

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+package androidx.demo.`var`.ui.theme
+
+import androidx.compose.ui.graphics.Color
+
+val Purple200 = Color(0xFFBB86FC)
+val Purple500 = Color(0xFF6200EE)
+val Purple700 = Color(0xFF3700B3)
+val Teal200 = Color(0xFF03DAC5)

demoProjects/Var/app/src/main/java/androidx/demo/var/ui/theme/Shape.kt

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+package androidx.demo.`var`.ui.theme
+
+import androidx.compose.foundation.shape.RoundedCornerShape
+import androidx.compose.material.Shapes
+import androidx.compose.ui.unit.dp
+
+val Shapes = Shapes(
+    small = RoundedCornerShape(4.dp),
+    medium = RoundedCornerShape(4.dp),
+    large = RoundedCornerShape(0.dp)
+)

demoProjects/Var/app/src/main/java/androidx/demo/var/ui/theme/Theme.kt

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+package androidx.demo.`var`.ui.theme
+
+import androidx.compose.foundation.isSystemInDarkTheme
+import androidx.compose.material.MaterialTheme
+import androidx.compose.material.darkColors
+import androidx.compose.material.lightColors
+import androidx.compose.runtime.Composable
+
+private val DarkColorPalette = darkColors(
+    primary = Purple200,
+    primaryVariant = Purple700,
+    secondary = Teal200
+)
+
+private val LightColorPalette = lightColors(
+    primary = Purple500,
+    primaryVariant = Purple700,
+    secondary = Teal200
+
+    /* Other default colors to override
+    background = Color.White,
+    surface = Color.White,
+    onPrimary = Color.White,
+    onSecondary = Color.Black,
+    onBackground = Color.Black,
+    onSurface = Color.Black,
+    */
+)
+
+@Composable
+fun VarTheme(darkTheme: Boolean = isSystemInDarkTheme(), content: @Composable () -> Unit) {
+    val colors = if (darkTheme) {
+        DarkColorPalette
+    } else {
+        LightColorPalette
+    }
+
+    MaterialTheme(
+        colors = colors,
+        typography = Typography,
+        shapes = Shapes,
+        content = content
+    )
+}