Added module and BookFlipPageTransformer class

easyflipviewpager/.gitignore

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+/build

easyflipviewpager/build.gradle

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+apply plugin: 'com.android.library'
+
+android {
+    compileSdkVersion 28
+
+
+
+    defaultConfig {
+        minSdkVersion 15
+        targetSdkVersion 28
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+
+    implementation 'com.android.support:appcompat-v7:28.0.0'
+    testImplementation 'junit:junit:4.12'
+    androidTestImplementation 'com.android.support.test:runner:1.0.2'
+    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
+}

easyflipviewpager/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

easyflipviewpager/src/androidTest/java/com/wajahatkarim3/easyflipviewpager/ExampleInstrumentedTest.java

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+package com.wajahatkarim3.easyflipviewpager;
+
+import android.content.Context;
+import android.support.test.InstrumentationRegistry;
+import android.support.test.runner.AndroidJUnit4;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import static org.junit.Assert.*;
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
+ */
+@RunWith(AndroidJUnit4.class)
+public class ExampleInstrumentedTest {
+    @Test
+    public void useAppContext() {
+        // Context of the app under test.
+        Context appContext = InstrumentationRegistry.getTargetContext();
+
+        assertEquals("com.wajahatkarim3.easyflipviewpager.test", appContext.getPackageName());
+    }
+}

easyflipviewpager/src/main/AndroidManifest.xml

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+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+          package="com.wajahatkarim3.easyflipviewpager"/>

easyflipviewpager/src/main/java/com/wajahatkarim3/easyflipviewpager/BookFlipPageTransformer.java

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+package com.wajahatkarim3.easyflipviewpager;
+
+import android.support.annotation.NonNull;
+import android.support.v4.view.ViewPager;
+import android.view.View;
+
+/**
+ * A book based page flip animation PageTransformer implementation for ViewPager
+ *
+ * Set the object of this transformer to any ViewPager object.
+ * For example, myViewPager.setPageTransformer(true, new BookFlipPageTransformer());
+ *
+ * @see <a href="http://github.com/wajahatkarim3/EasyFlipViewPager">EasyFlipViewPager</a>
+ *
+ * @author Wajahat Karim (http://wajahatkarim.com)
+ */
+public class BookFlipPageTransformer implements ViewPager.PageTransformer {
+
+    private final int LEFT = -1;
+    private final int RIGHT = 1;
+    private final int CENTER = 0;
+
+    @Override
+    public void transformPage(@NonNull View page, float position) {
+        float percentage = 1 - Math.abs(position);
+        // Don't move pages once they are on left or right
+        if (position > CENTER && position <= RIGHT)
+        {
+            // This is behind page
+            page.setVisibility(View.VISIBLE);
+            page.setTranslationX(-position * (page.getWidth()));
+            page.setTranslationY(0);
+            page.setRotation(0);
+        }
+        // Otherwise flip the current page
+        else
+        {
+            flipPage(page, position, percentage);
+        }
+    }
+
+    private void flipPage(View page, float position, float percentage)
+    {
+        // Flip this page
+        page.setCameraDistance(-20000);
+        setVisibility(page, position);
+        setTranslation(page);
+        setPivot(page, 0f, page.getHeight() * 0.5f);
+        setRotation(page, position, percentage);
+    }
+
+    private void setPivot(View page, float pivotX, float pivotY)
+    {
+        page.setPivotX(pivotX);
+        page.setPivotY(pivotY);
+    }
+
+    private void setVisibility(View page, float position) {
+        if (position < 0.5 && position > -0.5) {
+            page.setVisibility(View.VISIBLE);
+        } else {
+            page.setVisibility(View.INVISIBLE);
+        }
+    }
+
+    private void setTranslation(View page) {
+        ViewPager viewPager = (ViewPager) page.getParent();
+        int scroll = viewPager.getScrollX() - page.getLeft();
+        page.setTranslationX(scroll);
+    }
+
+    private void setSize(View page, float position, float percentage) {
+        page.setScaleX((position != 0 && position != 1) ? percentage : 1);
+        page.setScaleY((position != 0 && position != 1) ? percentage : 1);
+    }
+
+    private void setRotation(View page, float position, float percentage) {
+        if (position > 0) {
+            page.setRotationY(-180 * (percentage + 1));
+        } else {
+            page.setRotationY(180 * (percentage + 1));
+        }
+    }
+}

easyflipviewpager/src/main/res/values/strings.xml

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+<resources>
+    <string name="app_name">EasyFlipViewPager</string>
+</resources>

easyflipviewpager/src/test/java/com/wajahatkarim3/easyflipviewpager/ExampleUnitTest.java

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+package com.wajahatkarim3.easyflipviewpager;
+
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * @see <a href="http://d.android.com/tools/testing">Testing documentation</a>
+ */
+public class ExampleUnitTest {
+    @Test
+    public void addition_isCorrect() {
+        assertEquals(4, 2 + 2);
+    }
+}

settings.gradle

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-include ':app'
+include ':app', ':easyflipviewpager'