Egor Shakhmin. Homework with cache

app/build.gradle

@@ -1,13 +1,13 @@
 apply plugin: 'com.android.application'
 
 android {
-    compileSdkVersion 23
-    buildToolsVersion "23.0.1"
+    compileSdkVersion 28
+    buildToolsVersion '28.0.3'
 
     defaultConfig {
         applicationId "ru.android_2019.citycam"
         minSdkVersion 14
-        targetSdkVersion 22
+        targetSdkVersion 28
         versionCode 1
         versionName "1.0"
     }
@@ -17,11 +17,18 @@ android {
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
         }
     }
+
+    repositories {
+        jcenter()
+        google()
+    }
 }
 
 dependencies {
-    compile fileTree(dir: 'libs', include: ['*.jar'])
-    testCompile 'junit:junit:4.12'
-    compile 'com.android.support:appcompat-v7:23.0.1'
-    compile 'com.android.support:recyclerview-v7:23.0.1'
+    implementation fileTree(dir: 'libs', include: ['*.jar'])
+    testImplementation 'junit:junit:4.12'
+    implementation 'com.android.support:appcompat-v7:28.0.0'
+    implementation 'com.android.support:recyclerview-v7:28.0.0'
+    implementation "android.arch.persistence.room:runtime:1.1.1"
+    annotationProcessor "android.arch.persistence.room:compiler:1.1.1"
 }

app/src/main/AndroidManifest.xml

@@ -2,6 +2,8 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="ru.android_2019.citycam" >
 
+    <uses-permission android:name="android.permission.INTERNET" />
+
     <application
         android:allowBackup="true"
         android:icon="@mipmap/ic_launcher"

app/src/main/java/ru/android_2019/citycam/CityCamActivity.java

@@ -1,13 +1,18 @@
 package ru.android_2019.citycam;
 
+import android.arch.persistence.room.Room;
 import android.os.Bundle;
 import android.support.v7.app.AppCompatActivity;
 import android.util.Log;
 import android.view.View;
 import android.widget.ImageView;
 import android.widget.ProgressBar;
+import android.widget.TextView;
 
 import ru.android_2019.citycam.model.City;
+import ru.android_2019.citycam.webcams.store.WebcamDao;
+import ru.android_2019.citycam.webcams.store.WebcamDatabase;
+import ru.android_2019.citycam.webcams.tasks.WebcamsTask;
 
 /**
  * Экран, показывающий веб-камеру одного выбранного города.
@@ -21,9 +26,39 @@ public class CityCamActivity extends AppCompatActivity {
     public static final String EXTRA_CITY = "city";
 
     private City city;
-
     private ImageView camImageView;
     private ProgressBar progressView;
+    private TextView titleImageView;
+    private WebcamsTask task;
+    private WebcamDao webcamDao;
+
+    public City getCity() {
+        return city;
+    }
+
+    public ImageView getCamImageView() {
+        return camImageView;
+    }
+
+    public ProgressBar getProgressView() {
+        return progressView;
+    }
+
+    public TextView getTitleImageView() {
+        return titleImageView;
+    }
+
+    public WebcamDao getWebcamDao() {
+        return webcamDao;
+    }
+
+    @Override
+    public Object onRetainCustomNonConfigurationInstance() {
+        if (task != null) {
+            task.attachActivity(null);
+        }
+        return task;
+    }
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -36,15 +71,24 @@ protected void onCreate(Bundle savedInstanceState) {
         }
 
         setContentView(R.layout.activity_city_cam);
-        camImageView = (ImageView) findViewById(R.id.cam_image);
-        progressView = (ProgressBar) findViewById(R.id.progress);
+        camImageView = findViewById(R.id.cam_image);
+        progressView = findViewById(R.id.progress);
+        titleImageView = findViewById(R.id.cam_image_title);
 
-        getSupportActionBar().setTitle(city.name);
+        WebcamDatabase db =  Room.databaseBuilder(getApplicationContext(),
+                WebcamDatabase.class, "webcam-database").build();
+        this.webcamDao = db.webcamDao();
 
-        progressView.setVisibility(View.VISIBLE);
+        getSupportActionBar().setTitle(city.name);
 
-        // Здесь должен быть код, инициирующий асинхронную загрузку изображения с веб-камеры
-        // в выбранном городе.
+        task = (WebcamsTask) getLastCustomNonConfigurationInstance();
+        if (task == null) {
+            progressView.setVisibility(View.VISIBLE);
+            task = new WebcamsTask();
+            task.execute();
+        }
+        task.attachActivity(this);
+        task.updateView();
     }
 
     private static final String TAG = "CityCam";

app/src/main/java/ru/android_2019/citycam/webcams/api/WebcamsAPI.java

@@ -0,0 +1,44 @@
+package ru.android_2019.citycam.webcams.api;
+
+import android.net.Uri;
+
+import java.io.IOException;
+import java.net.HttpURLConnection;
+import java.net.URL;
+
+/**
+ * Константы для работы с WebcamsAPI API
+ */
+public final class WebcamsAPI {
+
+    private static final String KEY_HEADER_NAME = "X-RapidAPI-Key";
+    private static final String RAPID_API_KEY = "9874e23cf2msh03710ad1d33c9bbp15fca7jsnee66756f171d";
+    private static final String BASE_URL = "https://webcamstravel.p.rapidapi.com";
+    private static final String PARAM_LAN = "lan";
+    private static final String PARAM_SHOW = "show";
+    private static final String LAN = "en";
+    private static final String SHOW = "webcams:base,image,location";
+
+    /**
+     * Возвращает HttpURLConnection для выполнения запроса WebcamsAPI API для получения
+     * информации о веб-камерах рядом с указанными координатами в формате JSON.
+     */
+    public static HttpURLConnection createNearbyUrl(double latitude,
+                                                    double longitude,
+                                                    double radius) throws IOException {
+
+        Uri uri = Uri.parse(BASE_URL).buildUpon()
+                .appendPath("webcams")
+                .appendPath("list")
+                .appendEncodedPath("nearby=" + latitude + "," + longitude + "," + radius)
+                .appendQueryParameter(PARAM_LAN, LAN)
+                .appendQueryParameter(PARAM_SHOW, SHOW)
+                .build();
+        HttpURLConnection connection = (HttpURLConnection) new URL(uri.toString()).openConnection();
+        connection.setRequestMethod("GET");
+        connection.setRequestProperty(KEY_HEADER_NAME, RAPID_API_KEY);
+        return connection;
+    }
+
+    private WebcamsAPI() {}
+}

app/src/main/java/ru/android_2019/citycam/webcams/exceptions/BadResponseException.java

@@ -0,0 +1,8 @@
+package ru.android_2019.citycam.webcams.exceptions;
+
+public class BadResponseException extends Exception {
+
+    public BadResponseException(String message) {
+        super(message);
+    }
+}

app/src/main/java/ru/android_2019/citycam/webcams/parser/WebcamsResponseParser.java

@@ -0,0 +1,142 @@
+package ru.android_2019.citycam.webcams.parser;
+
+import android.util.JsonReader;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.util.ArrayList;
+import java.util.List;
+
+import ru.android_2019.citycam.webcams.store.Webcam;
+import ru.android_2019.citycam.webcams.store.Webcam.TypeImage;
+import ru.android_2019.citycam.webcams.exceptions.BadResponseException;
+
+public final class WebcamsResponseParser {
+
+    public static List<Webcam> parseWebcamsResponse(
+            String cityName,
+            InputStream in,
+            String charset) throws IOException, BadResponseException {
+
+        JsonReader reader = new JsonReader(new InputStreamReader(in, charset));
+        List<Webcam> webcams = new ArrayList<>();
+
+        reader.beginObject();
+        while (reader.hasNext()){
+            String name = reader.nextName();
+            if (name.equals("result")) {
+                webcams = readResult(cityName, reader);
+            } else if (name.equals("status")){
+                String status = reader.nextString();
+                if (!status.equals("OK")) {
+                    throw new BadResponseException("Bad response with status: " + status);
+                }
+            } else {
+                reader.skipValue();
+            }
+        }
+        reader.endObject();
+
+        return webcams;
+    }
+
+    private static List<Webcam> readResult(
+            String cityName,
+            JsonReader reader) throws IOException {
+
+        List<Webcam> webcams = new ArrayList<>();
+
+        reader.beginObject();
+        while (reader.hasNext()) {
+            String name = reader.nextName();
+            if (name.equals("webcams")) {
+                webcams = readWebcamsArray(cityName, reader);
+            } else {
+                reader.skipValue();
+            }
+        }
+        reader.endObject();
+
+        return webcams;
+    }
+
+    private static List<Webcam> readWebcamsArray(
+            String cityName,
+            JsonReader reader) throws IOException {
+
+        List<Webcam> webcams = new ArrayList<>();
+
+        reader.beginArray();
+        while (reader.hasNext()) {
+            webcams.add(readWebcam(cityName, reader));
+        }
+        reader.endArray();
+
+        return webcams;
+    }
+
+    private static Webcam readWebcam(
+            String cityName,
+            JsonReader reader) throws IOException {
+
+        String title = null;
+        String imageUrl = null;
+
+        reader.beginObject();
+        while (reader.hasNext()) {
+            String name = reader.nextName();
+            if (name.equals("title")) {
+                title = reader.nextString();
+            } else if (name.equals("image")) {
+                imageUrl = readImages(reader);
+            } else {
+                reader.skipValue();
+            }
+        }
+        reader.endObject();
+        Webcam webcam = new Webcam(cityName);
+        webcam.setTitle(title);
+        webcam.setImageUrl(imageUrl);
+        return webcam;
+    }
+
+    private static String readImages(JsonReader reader)
+            throws IOException {
+
+        String imageUrl = null;
+
+        reader.beginObject();
+        while (reader.hasNext()) {
+            String name = reader.nextName();
+            if (name.equals("current")) {
+                imageUrl = readImageUrl(reader);
+            } else {
+                reader.skipValue();
+            }
+        }
+        reader.endObject();
+
+        return imageUrl;
+    }
+
+    private static String readImageUrl(JsonReader reader)
+            throws IOException {
+
+        String imageUrl = null;
+
+        reader.beginObject();
+        while (reader.hasNext()) {
+            String name = reader.nextName();
+            if (name.equals(TypeImage.PREVIEW.getName())) {
+                imageUrl = reader.nextString();
+            } else {
+                reader.skipValue();
+            }
+
+        }
+        reader.endObject();
+
+        return imageUrl;
+    }
+}