add a standard constraint chain syntax

constraintlayout/constraintlayout/src/main/java/androidx/constraintlayout/motion/widget/MotionScene.java

@@ -1271,7 +1271,7 @@ private void load(Context context, int resourceId) {
  break;
  case ONCLICK_TAG:
  if (transition != null) {
- if (mMotionLayout.isInEditMode()) {
+ if (!mMotionLayout.isInEditMode()) {
  transition.addOnClick(context, parser);
  }
  }

constraintlayout/core/src/main/java/androidx/constraintlayout/core/state/ConstraintSetParser.java

@@ -22,6 +22,7 @@
 
 import androidx.constraintlayout.core.motion.utils.TypedBundle;
 import androidx.constraintlayout.core.motion.utils.TypedValues;
+import androidx.constraintlayout.core.motion.utils.Utils;
 import androidx.constraintlayout.core.parser.CLArray;
 import androidx.constraintlayout.core.parser.CLElement;
 import androidx.constraintlayout.core.parser.CLKey;
@@ -514,6 +515,16 @@ public static void parseJSON(String content, State state,
  case "barrier":
  parseBarrier(state, elementName, (CLObject) element);
  break;
+ case "vChain":
+ case "hChain":
+ parseChainType(
+ type,
+ state,
+ elementName,
+ layoutVariables,
+ (CLObject) element
+ );
+ break;
  }
  } else {
  parseWidget(state, layoutVariables,
@@ -726,6 +737,114 @@ static void parseChain(int orientation, State state,
  }
  }
 
+ private static float toPix(State state, float dp){
+ return state.getDpToPixel().toPixels(dp);
+ }
+ /**
+ * Support parsing Chain in the following manner
+ * chainId : {
+ * type:'hChain' // or vChain
+ * contains: ['id1', 'id2', 'id3' ]
+ * contains: [['id', weight, marginL ,marginR], 'id2', 'id3' ]
+ * start: ['parent', 'start',0],
+ * end: ['parent', 'end',0],
+ * top: ['parent', 'top',0],
+ * bottom: ['parent', 'bottom',0],
+ * style: 'spread'
+ * }
+
+ * @throws CLParsingException
+ */
+ static void parseChainType(String orientation,
+ State state,
+ String chainName,
+ LayoutVariables margins,
+ CLObject object) throws CLParsingException {
+
+ ChainReference chain = (orientation.charAt(0) == 'h')
+ ? state.horizontalChain() : state.verticalChain();
+ chain.setKey(chainName);
+
+ for (String params : object.names()) {
+ switch (params) {
+ case "contains":
+ CLElement refs = object.get(params);
+ if (!(refs instanceof CLArray) || ((CLArray) refs).size() < 1) {
+ System.err.println(
+ chainName + " contains should be an array \"" + refs.content()
+ + "\"");
+ return;
+ }
+ for (int i = 0; i < ((CLArray) refs).size(); i++) {
+ CLElement chainElement = ((CLArray) refs).get(i);
+ Utils.log("================ " + i + " " + chainElement.getClass() + " "
+ + chainElement.content());
+ if (chainElement instanceof CLArray) {
+ CLArray array = (CLArray) chainElement;
+ if (array.size() == 1) {
+ chain.add(array.get(0).content());
+ } else {
+ String id = array.get(0).content();
+ float weight = Float.NaN;
+ float preMargin = Float.NaN;
+ float postMargin = Float.NaN;
+
+ if (array.size() >= 2) {
+ weight = array.getFloat(1);
+ if (array.size() >= 3) {
+ postMargin = preMargin = toPix(state, array.getFloat(2));
+ if (array.size() >= 4) {
+ postMargin = toPix(state, array.getFloat(3));
+ }
+ }
+ }
+
+ chain.addChainElement(id, weight, preMargin, postMargin);
+ }
+
+ } else {
+ chain.add(chainElement.content());
+ }
+ }
+ break;
+ case "start":
+ case "end":
+ case "top":
+ case "bottom":
+ case "left":
+ case "right":
+ parseConstraint(state, margins, object, chain, params);
+ break;
+ case "style":
+
+ CLElement styleObject = object.get(params);
+ String styleValue;
+ if (styleObject instanceof CLArray && ((CLArray) styleObject).size() > 1) {
+ styleValue = ((CLArray) styleObject).getString(0);
+ float biasValue = ((CLArray) styleObject).getFloat(1);
+ chain.bias(biasValue);
+ } else {
+ styleValue = styleObject.content();
+ }
+ switch (styleValue) {
+ case "packed":
+ chain.style(State.Chain.PACKED);
+ break;
+ case "spread_inside":
+ chain.style(State.Chain.SPREAD_INSIDE);
+ break;
+ default:
+ chain.style(State.Chain.SPREAD);
+ break;
+ }
+
+ break;
+ }
+ }
+ Utils.log(" ");
+
+ }
+
 
  static void parseGuideline(int orientation,
  State state, CLArray helper) throws CLParsingException {

constraintlayout/core/src/main/java/androidx/constraintlayout/core/state/helpers/ChainReference.java

@@ -19,9 +19,15 @@
 import androidx.constraintlayout.core.state.HelperReference;
 import androidx.constraintlayout.core.state.State;
 
+import java.util.HashMap;
+
 public class ChainReference extends HelperReference {
 
  protected float mBias = 0.5f;
+ protected HashMap<String ,Float> mMapWeights;
+ protected HashMap<String,Float> mMapPreMargin;
+ protected HashMap<String,Float> mMapPostMargin;
+
  protected State.Chain mStyle = State.Chain.SPREAD;
 
  public ChainReference(State state, State.Helper type) {
@@ -40,6 +46,52 @@ public ChainReference style(State.Chain style) {
  return this;
  }
 
+ public void addChainElement(String id, float weight, float preMargin, float postMargin ) {
+ super.add(id);
+ if (!Float.isNaN(weight)) {
+ if (mMapWeights == null) {
+ mMapWeights = new HashMap<>();
+ }
+ mMapWeights.put(id, weight);
+ }
+ if (!Float.isNaN(preMargin)) {
+ if (mMapPreMargin == null) {
+ mMapPreMargin = new HashMap<>();
+ }
+ mMapPreMargin.put(id, preMargin);
+ }
+ if (!Float.isNaN(postMargin)) {
+ if (mMapPostMargin == null) {
+ mMapPostMargin = new HashMap<>();
+ }
+ mMapPostMargin.put(id, postMargin);
+ }
+ }
+
+ protected float getWeight(String id) {
+ if (mMapWeights == null) {
+ return -1;
+ }
+ if (mMapWeights.containsKey(id)) {
+ return mMapWeights.get(id);
+ }
+ return 1;
+ }
+
+ protected float getPostMargin(String id) {
+ if (mMapPostMargin != null && mMapPostMargin.containsKey(id)) {
+ return mMapPostMargin.get(id);
+ }
+ return 0;
+ }
+
+ protected float getPreMargin(String id) {
+ if (mMapPreMargin != null && mMapPreMargin.containsKey(id)) {
+ return mMapPreMargin.get(id);
+ }
+ return 0;
+ }
+
  public float getBias() {
  return mBias;
  }

constraintlayout/core/src/main/java/androidx/constraintlayout/core/state/helpers/HorizontalChainReference.java

@@ -39,6 +39,7 @@ public void apply() {
 
  for (Object key : mReferences) {
  ConstraintReference reference = mState.constraints(key);
+
  if (first == null) {
  first = reference;
  if (mStartToStart != null) {
@@ -55,13 +56,17 @@ public void apply() {
  first.startToEnd(mLeftToRight).margin(mMarginLeft).marginGone(mMarginLeftGone);
  } else {
  // No constraint declared, default to Parent.
- first.startToStart(State.PARENT);
+ String refKey = reference.getKey().toString();
+ first.startToStart(State.PARENT).margin(getPreMargin(refKey));
  }
  }
  if (previous != null) {
- previous.endToStart(reference.getKey());
- reference.startToEnd(previous.getKey());
+ String preKey = previous.getKey().toString();
+ String refKey = reference.getKey().toString();
+ previous.endToStart(reference.getKey()).margin(getPostMargin(preKey));
+ reference.startToEnd(previous.getKey()).margin(getPreMargin(refKey));;
  }
+ reference.setHorizontalChainWeight(getWeight(key.toString()));
  previous = reference;
  }
 
@@ -78,7 +83,8 @@ public void apply() {
  previous.endToEnd(mRightToRight).margin(mMarginRight).marginGone(mMarginRightGone);
  } else {
  // No constraint declared, default to Parent.
- previous.endToEnd(State.PARENT);
+ String preKey = previous.getKey().toString();
+ previous.endToEnd(State.PARENT).margin(getPostMargin(preKey));
  }
  }
 

constraintlayout/core/src/main/java/androidx/constraintlayout/core/state/helpers/VerticalChainReference.java

@@ -47,13 +47,17 @@ public void apply() {
  first.topToBottom(mTopToBottom).margin(mMarginTop).marginGone(mMarginTopGone);
  } else {
  // No constraint declared, default to Parent.
- first.topToTop(State.PARENT);
+ String refKey = reference.getKey().toString();
+ first.topToTop(State.PARENT).margin(getPreMargin(refKey));
  }
  }
  if (previous != null) {
- previous.bottomToTop(reference.getKey());
- reference.topToBottom(previous.getKey());
+ String preKey = previous.getKey().toString();
+ String refKey = reference.getKey().toString();
+ previous.bottomToTop(reference.getKey()).margin(getPostMargin(preKey));;
+ reference.topToBottom(previous.getKey()).margin(getPreMargin(refKey));;;
  }
+ reference.setHorizontalChainWeight(getWeight(key.toString()));
  previous = reference;
  }
 
@@ -68,7 +72,8 @@ public void apply() {
  .marginGone(mMarginBottomGone);
  } else {
  // No constraint declared, default to Parent.
- previous.bottomToBottom(State.PARENT);
+ String preKey = previous.getKey().toString();
+ previous.bottomToBottom(State.PARENT).margin(getPostMargin(preKey));
  }
  }
 

demoProjects/ComposeConstraintLayoutDemo/.gitignore

@@ -0,0 +1,15 @@
+*.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/ComposeConstraintLayoutDemo/app/.gitignore

@@ -0,0 +1 @@
+/build

demoProjects/ComposeConstraintLayoutDemo/app/build.gradle

@@ -0,0 +1,64 @@
+plugins {
+ id 'com.android.application'
+ id 'org.jetbrains.kotlin.android'
+}
+
+android {
+ namespace 'androidx.demo.motiondemos'
+ compileSdk 32
+
+ defaultConfig {
+ applicationId "androidx.demo.motiondemos"
+ 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.core:core-ktx:1.7.0'
+ implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
+ implementation 'androidx.activity:activity-compose:1.3.1'
+ implementation 'androidx.constraintlayout:constraintlayout-compose:1.1.0-alpha01'
+ 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'
+ 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/ComposeConstraintLayoutDemo/app/proguard-rules.pro

@@ -0,0 +1,21 @@
+# 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