Added MaterialTextView component, which supports the ability to pass …

…the line height value via text appearance style.

PiperOrigin-RevId: 254790727

docs/components/MaterialTextView.md

@@ -0,0 +1,54 @@
+<!--docs:
+title: "Material Text View"
+layout: detail
+section: components
+excerpt: "MaterialTextView displays text to the user."
+iconId: text_view
+path: /catalog/material-text-view/
+-->
+
+# Material Text View
+
+A MaterialTextView is a derivative of AppCompatTextView that displays text to
+the user. To provide user-editable text, see {@link EditText}.
+
+## Design & API Documentation
+
+-   [Class definition](https://github.com/material-components/material-components-android/tree/master/lib/java/com/google/android/material/textview/MaterialTextView.java)
+    <!--{: .icon-list-item.icon-list-item--link }-->
+
+## Usage
+
+Example code of how to include the component in your layout is listed here for
+reference.
+
+```xml
+<LinearLayout
+  xmlns:android="http://schemas.android.com/apk/res/android"
+  android:layout_width="match_parent"
+  android:layout_height="match_parent">
+    <MaterialTextView
+      android:id="@+id/text_view_id"
+      android:layout_height="wrap_content"
+      android:layout_width="wrap_content"
+      android:text="@string/hello" />
+</LinearLayout>
+```
+
+### Attributes
+
+`MaterialTextView` supports all of the standard attributes that can be changed
+for a
+[`AppCompatTextView`](https://developer.android.com/reference/android/support/v7/widget/AppCompatTextView).
+Unlike the `AppCompatTextView` which supports specifying the line height only in
+a view layout XML, `MaterialTextView` supports the ability to read the line
+height from a `TextAppearance` style, which can be applied to the
+`MaterialTextView` either using the `style` attribute or using the
+`android:textAppearance` attribute.
+
+The following additional attributes can be changed in `TextAppearance` and
+applied to a `MaterialTextView`:
+
+Feature     | Relevant attributes
+:---------- | :-------------------
+Line Height | `android:lineHeight`

lib/build.gradle

@@ -67,6 +67,7 @@ def srcDirs = [
   'com/google/android/material/switchmaterial',
   'com/google/android/material/tabs',
   'com/google/android/material/textfield',
+  'com/google/android/material/textview',
   'com/google/android/material/theme',
   'com/google/android/material/transformation',
   'com/google/android/material/typography',

lib/java/com/google/android/material/textview/AndroidManifest.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright 2019 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
+  ~
+  ~     https://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.
+  -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+  package="com.google.android.material.textview">
+
+  <application/>
+</manifest>

lib/java/com/google/android/material/textview/MaterialTextView.java

@@ -0,0 +1,162 @@
+/*
+ * Copyright (C) 2019 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.google.android.material.textview;
+
+import com.google.android.material.R;
+
+import android.content.Context;
+import android.content.res.Resources;
+import android.content.res.Resources.Theme;
+import android.content.res.TypedArray;
+import androidx.appcompat.widget.AppCompatTextView;
+import android.util.AttributeSet;
+import android.widget.EditText;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+/**
+ * A MaterialTextView is a derivative of {@link AppCompatTextView} that displays text to the user.
+ * To provide user-editable text, see {@link EditText}.
+ *
+ * <p>MaterialTextView supports the ability to read and apply {@code android:lineHeight} value from
+ * a {@code TextAppearance} style.
+ *
+ * <p>The following code sample shows a typical use, with an XML layout and code to modify the
+ * contents of the material text view:
+ *
+ * <pre>
+ * &lt;LinearLayout
+ * xmlns:android="http://schemas.android.com/apk/res/android"
+ * android:layout_width="match_parent"
+ * android:layout_height="match_parent"&gt;
+ *    &lt;MaterialTextView
+ *        android:id="@+id/text_view_id"
+ *        android:layout_height="wrap_content"
+ *        android:layout_width="wrap_content"
+ *        android:text="@string/hello" /&gt;
+ * &lt;/LinearLayout&gt;
+ * </pre>
+ *
+ * <p>This code sample demonstrates how to modify the contents of the material text view defined in
+ * the previous XML layout:
+ *
+ * <pre>
+ * public class MainActivity extends Activity {
+ *
+ *    protected void onCreate(Bundle savedInstanceState) {
+ *         super.onCreate(savedInstanceState);
+ *         setContentView(R.layout.activity_main);
+ *         final MaterialTextView textView = (MaterialTextView) findViewById(R.id.text_view_id);
+ *         textView.setText(R.string.user_greeting);
+ *     }
+ * }
+ * </pre>
+ *
+ * <p>To customize the appearance of MaterialTextView, see <a
+ * href="https://developer.android.com/guide/topics/ui/themes.html">Styles and Themes</a>.
+ */
+public class MaterialTextView extends AppCompatTextView {
+
+  /**
+   * Flag that will be used to avoid applying line height more than once when {@link
+   * #setTextAppearance(int)} method is called, the base implementation of which may call the {@link
+   * #setTextAppearance(Context, int)} internally.
+   */
+  private final AtomicBoolean skipApplyingLineHeight = new AtomicBoolean();
+
+  public MaterialTextView(Context context) {
+    this(context, null /* attrs */);
+  }
+
+  public MaterialTextView(Context context, AttributeSet attrs) {
+    this(context, attrs, android.R.attr.textViewStyle);
+  }
+
+  public MaterialTextView(Context context, AttributeSet attrs, int defStyleAttr) {
+    this(context, attrs, defStyleAttr, 0);
+  }
+
+  public MaterialTextView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
+    super(context, attrs, defStyleAttr);
+
+    final Resources.Theme theme = context.getTheme();
+
+    if (readLineHeightFromLayout(theme, attrs, defStyleAttr, defStyleRes) < 0) {
+      int resId = findViewAppearanceResourceId(theme, attrs, defStyleAttr, defStyleRes);
+      if (resId != -1) {
+        applyLineHeightFromViewAppearance(theme, resId);
+      }
+    }
+  }
+
+  @Override
+  public void setTextAppearance(int resId) {
+    skipApplyingLineHeight.set(true);
+    super.setTextAppearance(resId);
+    skipApplyingLineHeight.set(false);
+    applyLineHeightFromViewAppearance(getContext().getTheme(), resId);
+  }
+
+  @Override
+  public void setTextAppearance(Context context, int resId) {
+    super.setTextAppearance(context, resId);
+    if (!skipApplyingLineHeight.get()) {
+      applyLineHeightFromViewAppearance(context.getTheme(), resId);
+    }
+  }
+
+  private void applyLineHeightFromViewAppearance(Theme theme, int resId) {
+    TypedArray attributes = theme.obtainStyledAttributes(resId, R.styleable.MaterialTextAppearance);
+    int lineHeight = readLineHeighAttribute(attributes);
+    attributes.recycle();
+
+    if (lineHeight >= 0) {
+      setLineHeight(lineHeight);
+    }
+  }
+
+  private static int readLineHeightFromLayout(
+      Theme theme, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
+    TypedArray attributes =
+        theme.obtainStyledAttributes(
+            attrs, R.styleable.MaterialTextView, defStyleAttr, defStyleRes);
+    int lineHeight = readLineHeighAttribute(attributes);
+    attributes.recycle();
+
+    return lineHeight;
+  }
+
+  private static int readLineHeighAttribute(TypedArray attributes) {
+    int lineHeight =
+        attributes.getDimensionPixelSize(R.styleable.MaterialTextView_android_lineHeight, -1);
+    if (lineHeight < 0) {
+      lineHeight = attributes.getDimensionPixelSize(R.styleable.MaterialTextView_lineHeight, -1);
+    }
+
+    return lineHeight;
+  }
+
+  private static int findViewAppearanceResourceId(
+      Theme theme, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
+    TypedArray attributes =
+        theme.obtainStyledAttributes(
+            attrs, R.styleable.MaterialTextView, defStyleAttr, defStyleRes);
+    int appearanceAttrId =
+        attributes.getResourceId(R.styleable.MaterialTextView_android_textAppearance, -1);
+    attributes.recycle();
+    return appearanceAttrId;
+  }
+}

lib/java/com/google/android/material/textview/build.gradle

@@ -0,0 +1,37 @@
+apply plugin: 'com.android.library'
+apply plugin: 'com.github.dcendents.android-maven'
+
+archivesBaseName = getArchivesBaseName(project.name)
+version = rootProject.ext.mdcLibraryVersion
+
+dependencies {
+  implementation compatibility("appcompat")
+
+  implementation project(fromPath("lib/java/com/google/android/material/animation"))
+  implementation project(fromPath("lib/java/com/google/android/material/internal"))
+  implementation project(fromPath("lib/java/com/google/android/material/math"))
+  implementation project(fromPath("lib/java/com/google/android/material/shape"))
+}
+
+android {
+  sourceSets {
+    main.manifest.srcFile 'AndroidManifest.xml'
+    main.java.srcDir '.'
+    main.java.excludes = [
+      '**/build/**',
+    ]
+    main.res.srcDirs = [
+      'res',
+      'res-public'
+    ]
+    main.assets.srcDir 'assets'
+  }
+}
+
+uploadArchives {
+  repositories {
+    mavenDeployer {
+      repository(url: rootProject.ext.mavenRepoUrl)
+    }
+  }
+}

lib/java/com/google/android/material/textview/res-public/values/public.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright 2019 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
+  ~
+  ~     https://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.
+  -->
+
+<!-- Definitions of attributes to be exposed as public -->
+<resources>
+  <public name="Widget.MaterialComponents.TextView" type="style" />
+</resources>

lib/java/com/google/android/material/textview/res/values/attrs.xml

@@ -0,0 +1,33 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright 2019 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
+  ~
+  ~     https://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.
+  -->
+<resources>
+
+  <declare-styleable name="MaterialTextAppearance" parent="TextAppearance">
+    <!--
+        Specifies explicit line height for this TextView. This is equivalent to the vertical
+        distance between subsequent baselines in the TextView.
+    -->
+    <attr name="android:lineHeight"/>
+    <attr name="lineHeight"/>
+  </declare-styleable>
+
+  <declare-styleable name="MaterialTextView" parent="AppCompatTextView">
+    <attr name="android:textAppearance"/>
+    <attr name="android:lineHeight"/>
+    <attr name="lineHeight"/>
+  </declare-styleable>
+</resources>

lib/java/com/google/android/material/textview/res/values/styles.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  ~ Copyright 2019 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
+  ~
+  ~     https://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.
+  -->
+<resources>
+
+  <!-- Base style for TextView. You should use one of the sub-styles instead. -->
+  <style name="Base.Widget.MaterialComponents.TextView" parent="Widget.AppCompat.TextView" />
+  <style name="Widget.MaterialComponents.TextView" parent="Base.Widget.MaterialComponents.TextView" />
+</resources>

lib/javatests/com/google/android/material/textview/AndroidManifest.xml

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright 2019 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.
+  -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:tools="http://schemas.android.com/tools"
+  package="com.google.android.material.textview">
+
+  <uses-sdk
+    tools:overrideLibrary="androidx.test.core"/>
+
+  <application/>
+</manifest>