Added virtual guideline barrier

app/src/main/AndroidManifest.xml

@@ -1,5 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     package="com.hossainkhan.android.demo">
 
     <application
@@ -9,7 +10,8 @@
         android:label="@string/app_name"
         android:roundIcon="@mipmap/ic_launcher_round"
         android:supportsRtl="true"
-        android:theme="@style/AppTheme">
+        android:theme="@style/AppTheme"
+        tools:ignore="AllowBackup,GoogleAppIndexingWarning">
         <activity android:name=".browse.LayoutBrowseActivity">
             <intent-filter>
                 <action android:name="android.intent.action.MAIN" />
@@ -26,6 +28,9 @@
         <activity
             android:name=".layoutpreview.LayoutChainStyleActivity"
             android:parentActivityName=".browse.LayoutBrowseActivity" />
+        <activity
+            android:name=".layoutpreview.LayoutGuidelineBarrierActivity"
+            android:parentActivityName=".browse.LayoutBrowseActivity" />
     </application>
 
 </manifest>

app/src/main/java/com/hossainkhan/android/demo/browse/LayoutBrowseActivity.kt

@@ -23,6 +23,7 @@ import androidx.recyclerview.widget.GridLayoutManager
 import androidx.recyclerview.widget.RecyclerView
 import com.hossainkhan.android.demo.R
 import com.hossainkhan.android.demo.layoutpreview.LayoutChainStyleActivity
+import com.hossainkhan.android.demo.layoutpreview.LayoutGuidelineBarrierActivity
 import com.hossainkhan.android.demo.layoutpreview.LayoutPreviewBaseActivity
 import com.hossainkhan.android.demo.layoutpreview.LayoutVisibilityGoneActivity
 import com.hossainkhan.android.demo.viewmodel.LayoutPreviewViewModelFactory
@@ -79,10 +80,16 @@ class LayoutBrowseActivity : AppCompatActivity() {
 
         when (layoutResId) {
             R.layout.preview_visibility_gone -> {
-                startActivity(LayoutVisibilityGoneActivity.createStartIntent(this))
+                startActivity(LayoutPreviewBaseActivity.createStartIntent(this,
+                        LayoutVisibilityGoneActivity::class.java, R.layout.preview_visibility_gone))
             }
             R.layout.preview_chain_style_main -> {
-                startActivity(LayoutChainStyleActivity.createStartIntent(this))
+                startActivity(LayoutPreviewBaseActivity.createStartIntent(this,
+                        LayoutChainStyleActivity::class.java, R.layout.preview_chain_style_main))
+            }
+            R.layout.preview_virtual_helper_barrier -> {
+                startActivity(LayoutPreviewBaseActivity.createStartIntent(this,
+                        LayoutGuidelineBarrierActivity::class.java, R.layout.preview_virtual_helper_barrier))
             }
             else -> {
                 startActivity(LayoutPreviewBaseActivity.createStartIntent(this, layoutResId))

app/src/main/java/com/hossainkhan/android/demo/dagger/ActivityBindingModule.kt

@@ -17,6 +17,7 @@
 package com.hossainkhan.android.demo.dagger
 
 import com.hossainkhan.android.demo.layoutpreview.LayoutChainStyleActivity
+import com.hossainkhan.android.demo.layoutpreview.LayoutGuidelineBarrierActivity
 import com.hossainkhan.android.demo.layoutpreview.LayoutPreviewBaseActivity
 import com.hossainkhan.android.demo.layoutpreview.LayoutVisibilityGoneActivity
 import dagger.Module
@@ -57,4 +58,8 @@ abstract class ActivityBindingModule {
     @ActivityScope
     @ContributesAndroidInjector
     abstract fun layoutChainActivity(): LayoutChainStyleActivity
+
+    @ActivityScope
+    @ContributesAndroidInjector
+    abstract fun layoutGuidelineBarrierActivity(): LayoutGuidelineBarrierActivity
 }

app/src/main/java/com/hossainkhan/android/demo/data/LayoutDataStore.kt

@@ -124,7 +124,18 @@ class LayoutDataStore @Inject constructor(
                     title = "Virtual Helper: Guideline",
                     description = "The Guideline object allows you to create Horizontal and Vertical guidelines which " +
                             "are positioned relative to the ConstraintLayout container." +
-                            "Widgets can then be positioned by constraining them to such guidelines. ")
+                            "Widgets can then be positioned by constraining them to such guidelines. "),
+
+            /*
+             * https://developer.android.com/training/constraint-layout/index.html#constrain-to-a-barrier
+             * https://constraintlayout.com/basics/barriers.html
+             */
+            LayoutInformation(
+                    layoutResourceId = R.layout.preview_virtual_helper_barrier,
+                    thumbnailResourceId = R.drawable.thumb_virtual_helper_barrier,
+                    title = "Virtual Helper: Barrier",
+                    description = "A Barrier references multiple widgets as input, and creates a virtual guideline " +
+                            "based on the most extreme widget on the specified side.")
 
 
             /*

app/src/main/java/com/hossainkhan/android/demo/layoutpreview/LayoutChainStyleActivity.kt

@@ -16,20 +16,16 @@
 
 package com.hossainkhan.android.demo.layoutpreview
 
-import android.content.Context
-import android.content.Intent
 import android.os.Bundle
+import android.view.View
+import android.widget.RadioButton
+import android.widget.TextView
 import androidx.annotation.StringRes
 import androidx.constraintlayout.widget.ConstraintLayout
 import androidx.constraintlayout.widget.ConstraintSet
-import androidx.constraintlayout.widget.ConstraintSet.CHAIN_PACKED
-import androidx.constraintlayout.widget.ConstraintSet.CHAIN_SPREAD
-import androidx.constraintlayout.widget.ConstraintSet.CHAIN_SPREAD_INSIDE
+import androidx.constraintlayout.widget.ConstraintSet.*
 import androidx.transition.TransitionManager
-import android.view.View
 import com.hossainkhan.android.demo.R
-import android.widget.RadioButton
-import android.widget.TextView
 import timber.log.Timber
 
 /**
@@ -39,19 +35,6 @@ import timber.log.Timber
  */
 class LayoutChainStyleActivity : LayoutPreviewBaseActivity() {
 
-    companion object {
-        /**
-         * Creates an intent with required information to start this activity.
-         *
-         * @param context Activity context.
-         */
-        fun createStartIntent(context: Context): Intent {
-            val intent = Intent(context, LayoutChainStyleActivity::class.java)
-            intent.putExtra(BUNDLE_KEY_LAYOUT_RESID, R.layout.preview_chain_style_main)
-            return intent
-        }
-    }
-
     private lateinit var constraintLayout: ConstraintLayout
     private lateinit var guideTextView: TextView
     /**

app/src/main/java/com/hossainkhan/android/demo/layoutpreview/LayoutGuidelineBarrierActivity.kt

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2019 Hossain Khan
+ *
+ * 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.hossainkhan.android.demo.layoutpreview
+
+import android.os.Bundle
+import android.widget.Button
+import android.widget.TextView
+import com.hossainkhan.android.demo.R
+
+/**
+ * Activity showcasing how virtual guideline barrier changes when a view length changes within the barrier.
+ *
+ * See https://developer.android.com/reference/android/support/constraint/Barrier
+ */
+class LayoutGuidelineBarrierActivity : LayoutPreviewBaseActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        // Setup additional view that is only available in this screen.
+        val toggleButton = findViewById<Button>(R.id.toggle_label_text_size)
+        val textLabel = findViewById<TextView>(R.id.text_label)
+
+        toggleButton.setOnClickListener {
+            if (textLabel.text == getString(R.string.barrier_label_text_small)) {
+                textLabel.setText(R.string.barrier_label_text_long)
+            } else {
+                textLabel.setText(R.string.barrier_label_text_small)
+            }
+        }
+    }
+}

app/src/main/java/com/hossainkhan/android/demo/layoutpreview/LayoutPreviewBaseActivity.kt

@@ -61,6 +61,19 @@ open class LayoutPreviewBaseActivity : AppCompatActivity() {
             intent.putExtra(BUNDLE_KEY_LAYOUT_RESID, layoutResourceId)
             return intent
         }
+
+        /**
+         * Creates an intent with required information to start child activity with specific interactive demo.
+         *
+         * @param context Activity context.
+         * @param clazz Activity class that has interactive demo.
+         * @param layoutResourceId The layout resource ID to load into the view.
+         */
+        fun <T> createStartIntent(context: Context, clazz: Class<T>, @LayoutRes layoutResourceId: Int): Intent {
+            val intent = Intent(context, clazz)
+            intent.putExtra(BUNDLE_KEY_LAYOUT_RESID, layoutResourceId)
+            return intent
+        }
     }
 
     @Inject

app/src/main/java/com/hossainkhan/android/demo/layoutpreview/LayoutVisibilityGoneActivity.kt

@@ -16,28 +16,17 @@
 
 package com.hossainkhan.android.demo.layoutpreview
 
-import android.content.Context
-import android.content.Intent
 import android.os.Bundle
 import android.view.View
 import android.widget.Button
 import com.hossainkhan.android.demo.R
 
+/**
+ * Activity showcasing how visibility GONE affects constraints.
+ *
+ * See https://developer.android.com/reference/android/support/constraint/ConstraintLayout#VisibilityBehavior
+ */
 class LayoutVisibilityGoneActivity : LayoutPreviewBaseActivity() {
-
-    companion object {
-        /**
-         * Creates an intent with required information to start this activity.
-         *
-         * @param context Activity context.
-         */
-        fun createStartIntent(context: Context): Intent {
-            val intent = Intent(context, LayoutVisibilityGoneActivity::class.java)
-            intent.putExtra(BUNDLE_KEY_LAYOUT_RESID, R.layout.preview_visibility_gone)
-            return intent
-        }
-    }
-
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)