Try to fix travis

.travis.yml

@@ -0,0 +1,61 @@
+language: android
+jdk: oraclejdk8
+
+env:
+  global:
+    - ANDROID_TARGET=android-22
+    - ANDROID_ABI=armeabi-v7a
+
+android:
+  components:
+    # Uncomment the lines below if you want to
+    # use the latest revision of Android SDK Tools
+    - tools
+    - platform-tools
+
+    # The BuildTools version used by your project
+    - build-tools-23.0.3
+
+    # The SDK version used to compile your project
+    # TODO: why is this here explicitly in addition to $ANDROID_TARGET below
+    - android-23
+
+    # Additional components
+    - extra-google-google_play_services
+    - extra-google-m2repository
+    - extra-android-m2repository
+
+    # The SDK version used to compile your project
+    - $ANDROID_TARGET
+
+    # Specify at least one system image,
+    # if you need to run emulator(s) during your tests.
+    # The line should look like this after interpolation:
+    # - sys-img-armeabi-v7a-android-22
+    - sys-img-${ANDROID_ABI}-${ANDROID_TARGET}
+
+licenses:
+    - 'android-sdk-license-.+'
+
+before_install:
+  # Accept sdk licenses
+  - yes | sdkmanager "platforms;android-29"
+
+  # Get gradle
+  - chmod +x gradlew
+  - wget http://services.gradle.org/distributions/gradle-5.3-bin.zip
+  - unzip -qq gradle-5.3-bin.zip
+  - export GRADLE_HOME=$PWD/gradle-5.3
+  - export PATH=$GRADLE_HOME/bin:$PATH
+
+  # Build the project
+  - gradle -v
+
+  # Start the emulator
+  - echo no | android create avd --force -n test -t $ANDROID_TARGET --abi $ANDROID_ABI
+  - emulator -avd test -no-skin -no-audio -no-window &
+  - android-wait-for-emulator
+  - adb shell input keyevent 82 &
+
+  # The app will now automatically be installed and tested via
+  # the command `gradle connectedCheck`

app/build.gradle

@@ -1,29 +1,34 @@
-apply plugin: 'com.android.application'
-
-android {
-    compileSdkVersion 29
-    buildToolsVersion "29.0.2"
-    defaultConfig {
-        applicationId "com.example.simpleparadox.listycity"
-        minSdkVersion 15
-        targetSdkVersion 29
-        versionCode 1
-        versionName "1.0"
-        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
-    }
-    buildTypes {
-        release {
-            minifyEnabled false
-            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
-        }
-    }
-}
-
-dependencies {
-    implementation fileTree(dir: 'libs', include: ['*.jar'])
-    implementation 'androidx.appcompat:appcompat:1.0.2'
-    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
-    testImplementation 'junit:junit:4.12'
-    androidTestImplementation 'androidx.test:runner:1.1.1'
-    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
-}
+apply plugin: 'com.android.application'
+
+android {
+    compileSdkVersion 29
+    buildToolsVersion "29.0.2"
+    defaultConfig {
+        applicationId "com.example.simpleparadox.listycity"
+        minSdkVersion 15
+        targetSdkVersion 29
+        versionCode 1
+        versionName "1.0"
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+    }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+    compileOptions {
+        sourceCompatibility = 1.8
+        targetCompatibility = 1.8
+    }
+}
+
+dependencies {
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    implementation 'androidx.appcompat:appcompat:1.0.2'
+    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
+    androidTestImplementation 'androidx.test:runner:1.1.1'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.0.1'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.3.1'
+}

app/src/androidTest/java/com/example/simpleparadox/listycity/ExampleInstrumentedTest.java

@@ -1,27 +1,28 @@
-package com.example.simpleparadox.listycity;
-
-import android.content.Context;
-
-import androidx.test.platform.app.InstrumentationRegistry;
-import androidx.test.ext.junit.runners.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.getInstrumentation().getTargetContext();
-
-        assertEquals("com.example.simpleparadox.listycity", appContext.getPackageName());
-    }
-}
+package com.example.simpleparadox.listycity;
+
+import android.content.Context;
+
+import androidx.test.platform.app.InstrumentationRegistry;
+import androidx.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.getInstrumentation().getTargetContext();
+
+        assertEquals("com.example.simpleparadox.listycity", appContext.getPackageName());
+    }
+}

app/src/main/java/com/example/simpleparadox/listycity/City.java

@@ -1,19 +1,24 @@
-package com.example.simpleparadox.listycity;
-
-public class City {
-    private String city;
-    private String province;
-
-    City(String city, String province){
-        this.city = city;
-        this.province = province;
-    }
-
-    String getCityName(){
-        return this.city;
-    }
-
-    String getProvinceName(){
-        return this.province;
-    }
-}
+package com.example.simpleparadox.listycity;
+
+public class City implements Comparable<City>{
+    private String city;
+    private String province;
+
+    City(String city, String province){
+        this.city = city;
+        this.province = province;
+    }
+
+    String getCityName(){
+        return this.city;
+    }
+
+    String getProvinceName(){
+        return this.province;
+    }
+
+    @Override
+    public int compareTo(City o) {
+        return city.compareTo(o.getCityName());
+    }
+}