upate demo to andoridX, fix crash error

Author: xiangdong.cheng

LICENSE

@@ -10,22 +10,27 @@ android {
         targetSdkVersion 27
         versionCode 1
         versionName "1.0"
-        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }
     buildTypes {
         release {
             minifyEnabled false
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
     }
+    compileOptions {
+        sourceCompatibility = 1.8
+        targetCompatibility = 1.8
+    }
+    buildToolsVersion = '29.0.3'
 }
 
 dependencies {
     implementation fileTree(include: ['*.jar'], dir: 'libs')
-    androidTestImplementation('com.android.support.test.espresso:espresso-core:2.2.2', {
+    androidTestImplementation('androidx.test.espresso:espresso-core:3.1.0', {
         exclude group: 'com.android.support', module: 'support-annotations'
     })
-    implementation 'com.android.support:appcompat-v7:28.0.0'
+    implementation 'androidx.appcompat:appcompat:1.1.0'
     testImplementation 'junit:junit:4.12'
     implementation project(':library')
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"

README.md

@@ -1,8 +1,8 @@
 package com.dx.dxloadingbutton;
 
 import android.content.Context;
-import android.support.test.InstrumentationRegistry;
-import android.support.test.runner.AndroidJUnit4;
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
 
 import org.junit.Test;
 import org.junit.runner.RunWith;

app/.gitignore

@@ -5,7 +5,7 @@ import android.graphics.LinearGradient
 import android.graphics.Shader
 import android.graphics.Typeface
 import android.os.Bundle
-import android.support.v7.app.AppCompatActivity
+import androidx.appcompat.app.AppCompatActivity
 import android.view.View
 import android.widget.Toast
 import com.dx.dxloadingbutton.demo.LoginDemoActivity

app/build.gradle

@@ -3,7 +3,7 @@ package com.dx.dxloadingbutton.demo
 import android.animation.Animator
 import android.content.Intent
 import android.os.Bundle
-import android.support.v7.app.AppCompatActivity
+import androidx.appcompat.app.AppCompatActivity
 import android.view.View
 import android.view.ViewAnimationUtils
 import android.view.animation.AccelerateDecelerateInterpolator

app/proguard-rules.pro

@@ -1,7 +1,7 @@
 package com.dx.dxloadingbutton.demo
 
 import android.os.Bundle
-import android.support.v7.app.AppCompatActivity
+import androidx.appcompat.app.AppCompatActivity
 
 import com.dx.dxloadingbutton.R