Use Jetifier

build.gradle

@@ -3,9 +3,10 @@
 buildscript {
     repositories {
         mavenCentral()
+        google()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:1.0.0-rc1'
+        classpath 'com.android.tools.build:gradle:4.2.1'
 
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
@@ -22,6 +23,7 @@ allprojects {
 
     repositories {
         mavenCentral()
+        google()
     }
 }
 

gradle.properties

@@ -11,4 +11,6 @@ POM_LICENCE_NAME=The Apache Software License, Version 2.0
 POM_LICENCE_URL=http://www.apache.org/licenses/LICENSE-2.0.txt
 POM_LICENCE_DIST=repo
 POM_DEVELOPER_ID=filippudak
-POM_DEVELOPER_NAME=Filip Pudak
+POM_DEVELOPER_NAME=Filip Pudak
+android.useAndroidX=true
+android.enableJetifier=true

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.2.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7.1-all.zip

library/build.gradle

@@ -1,20 +1,19 @@
 apply plugin: 'com.android.library'
 
 android {
-    compileSdkVersion 21
-    buildToolsVersion "21.1.1"
+    compileSdkVersion 30
 
     defaultConfig {
         minSdkVersion 4
-        targetSdkVersion 21
+        targetSdkVersion 30
         versionCode Integer.parseInt(project.VERSION_CODE)
         versionName project.VERSION_NAME
     }
 
 }
 
 dependencies {
-    compile 'com.android.support:support-v4:21.0.2'
+    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
 }
 
 apply from: '../maven_push.gradle'

library/src/main/java/com/filippudak/ProgressPieView/ProgressPieView.java

@@ -15,9 +15,10 @@
 import android.text.TextUtils;
 import android.util.AttributeSet;
 import android.util.DisplayMetrics;
-import android.support.v4.util.LruCache;
 import android.view.View;
 
+import androidx.collection.LruCache;
+
 public class ProgressPieView extends View {
 
     public interface OnProgressListener {

sample/build.gradle

@@ -1,20 +1,19 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 21
-    buildToolsVersion "21.1.1"
+    compileSdkVersion 30
 
     defaultConfig {
         applicationId "com.filippudak.ProgressPieView.sample"
-        minSdkVersion 8
-        targetSdkVersion 21
+        minSdkVersion 21
+        targetSdkVersion 30
         versionCode Integer.parseInt(project.VERSION_CODE)
         versionName project.VERSION_NAME
     }
 
 }
 
 dependencies {
-    compile 'com.android.support:appcompat-v7:21.0.2'
-    compile project(':library')
+    implementation 'androidx.appcompat:appcompat:1.0.0'
+    implementation project(':library')
 }

sample/src/main/java/com/filippudak/ProgressPieView/sample/MainActivity.java

@@ -1,17 +1,18 @@
 package com.filippudak.ProgressPieView.sample;
 
 import android.os.Bundle;
-import android.support.v7.app.ActionBarActivity;
 import android.view.Gravity;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.ViewGroup;
 import android.widget.LinearLayout;
 import android.widget.SeekBar;
 
+import androidx.appcompat.app.AppCompatActivity;
+
 import com.filippudak.ProgressPieView.ProgressPieView;
 
-public class MainActivity extends ActionBarActivity {
+public class MainActivity extends AppCompatActivity {
 
     private static final int SIZE = 96;
     private static final int MARGIN = 8;