Add listPhotos example

Author: JonasVautherin

examples/java-client/build.gradle

@@ -9,11 +9,6 @@ configurations {
     checkstyleClasspath
 }
 
-mainClassName = "io.mavsdk.example.TakeoffAndLand"
-
-sourceCompatibility = JavaVersion.VERSION_1_8
-targetCompatibility = JavaVersion.VERSION_1_8
-
 task takeoffAndLand(dependsOn: 'classes', type: JavaExec) {
     main = "io.mavsdk.example.TakeoffAndLand"
     classpath = sourceSets.main.runtimeClasspath
@@ -44,6 +39,11 @@ task runDownloadLastLog(dependsOn: 'classes', type: JavaExec) {
     classpath = sourceSets.main.runtimeClasspath
 }
 
+task listPhotos(dependsOn: 'classes', type: JavaExec) {
+    main = "io.mavsdk.example.ListPhotos"
+    classpath = sourceSets.main.runtimeClasspath
+}
+
 task checkstyle(type: Checkstyle) {
     configFile = rootProject.file("config/checkstyle/checkstyle.xml")
     source 'src'

examples/java-client/src/main/java/io/mavsdk/example/ListPhotos.java

@@ -0,0 +1,48 @@
+package io.mavsdk.example;
+
+import io.mavsdk.System;
+import io.mavsdk.camera.Camera;
+import io.reactivex.Completable;
+import io.reactivex.Single;
+
+import java.util.List;
+import java.util.concurrent.CountDownLatch;
+import java.util.concurrent.TimeUnit;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class ListPhotos {
+  private static final Logger logger = LoggerFactory.getLogger(ListPhotos.class);
+
+  public static void main(String[] args) {
+    logger.debug("Starting example: taking and listing photos...");
+
+    System drone = new System();
+    CountDownLatch latch = new CountDownLatch(1);
+
+    // Completable trying to take 50 pictures (stopping in case of error)
+    Completable takePhotoCompletable
+            = drone.getCamera().takePhoto()
+                .doOnComplete(() -> logger.debug("Picture taken"))
+                .doOnError(throwable -> logger.error("Error: " + throwable.getMessage()))
+                .onErrorComplete()
+                .delay(1, TimeUnit.SECONDS)
+                .repeat(50);
+
+    // Single getting a list of all the pictures available on the camera
+    Single<List<Camera.CaptureInfo>> photosList
+            = drone.getCamera().listPhotos(Camera.PhotosRange.ALL)
+            .doOnSuccess(captureInfos -> logger.debug("Got " + captureInfos.size() + " photos"))
+            .doOnError(throwable -> logger.error("Error: " + throwable.getMessage()));
+
+    // Run them one after the other
+    takePhotoCompletable.andThen(photosList)
+            .subscribe((captureInfos, throwable) -> latch.countDown());
+
+    try {
+      latch.await();
+    } catch (InterruptedException ignored) {
+      // This is expected
+    }
+  }
+}