Android os networkonmainthreadexception как исправить

There are many great answers already on this question, but a lot of great libraries have come out since those answers were posted. This is intended as a kind of newbie-guide.

I will cover several use cases for performing network operations and a solution or two for each.

REST over HTTP

Typically JSON, but it can be XML or something else.

Full API Access

Let’s say you are writing an app that lets users track stock prices, interest rates and currency exchange rates. You find an JSON API that looks something like this:

http://api.example.com/stocks                       // ResponseWrapper<String> object containing a
                                                    // list of strings with ticker symbols
http://api.example.com/stocks/$symbol               // Stock object
http://api.example.com/stocks/$symbol/prices        // PriceHistory<Stock> object
http://api.example.com/currencies                   // ResponseWrapper<String> object containing a
                                                    // list of currency abbreviation
http://api.example.com/currencies/$currency         // Currency object
http://api.example.com/currencies/$id1/values/$id2  // PriceHistory<Currency> object comparing the prices
                                                    // of the first currency (id1) to the second (id2)

Retrofit from Square

This is an excellent choice for an API with multiple endpoints and allows you to declare the REST endpoints instead of having to code them individually as with other libraries like Amazon Ion Java or Volley (website: Retrofit).

How do you use it with the finances API?

File build.gradle

Add these lines to your module level build.gradle file:

implementation 'com.squareup.retrofit2:retrofit:2.3.0' // Retrofit library, current as of September 21, 2017
implementation 'com.squareup.retrofit2:converter-gson:2.3.0' // Gson serialization and deserialization support for retrofit, version must match retrofit version

File FinancesApi.java

public interface FinancesApi {
    @GET("stocks")
    Call<ResponseWrapper<String>> listStocks();
    @GET("stocks/{symbol}")
    Call<Stock> getStock(@Path("symbol")String tickerSymbol);
    @GET("stocks/{symbol}/prices")
    Call<PriceHistory<Stock>> getPriceHistory(@Path("symbol")String tickerSymbol);

    @GET("currencies")
    Call<ResponseWrapper<String>> listCurrencies();
    @GET("currencies/{symbol}")
    Call<Currency> getCurrency(@Path("symbol")String currencySymbol);
    @GET("currencies/{symbol}/values/{compare_symbol}")
    Call<PriceHistory<Currency>> getComparativeHistory(@Path("symbol")String currency, @Path("compare_symbol")String currencyToPriceAgainst);
}

Class FinancesApiBuilder

public class FinancesApiBuilder {
    public static FinancesApi build(String baseUrl){
        return new Retrofit.Builder()
                    .baseUrl(baseUrl)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build()
                    .create(FinancesApi.class);
    }
}

Class FinancesFragment snippet

FinancesApi api = FinancesApiBuilder.build("http://api.example.com/"); //trailing '/' required for predictable behavior
api.getStock("INTC").enqueue(new Callback<Stock>(){
    @Override
    public void onResponse(Call<Stock> stockCall, Response<Stock> stockResponse){
        Stock stock = stockCall.body();
        // Do something with the stock
    }
    @Override
    public void onResponse(Call<Stock> stockCall, Throwable t){
        // Something bad happened
    }
}

If your API requires an API key or other header, like a user token, etc. to be sent, Retrofit makes this easy (see this awesome answer to Add Header Parameter in Retrofit for details).

One-off REST API access

Let’s say you’re building a “mood weather” app that looks up the user’s GPS location and checks the current temperature in that area and tells them the mood. This type of app doesn’t need to declare API endpoints; it just needs to be able to access one API endpoint.

Ion

This is a great library for this type of access.

Please read msysmilu’s great answer to How can I fix ‘android.os.NetworkOnMainThreadException’?.

Load images via HTTP

Volley

Volley can also be used for REST APIs, but due to the more complicated setup required, I prefer to use Retrofit from Square as above.

Let’s say you are building a social networking app and want to load profile pictures of friends.

File build.gradle

Add this line to your module level build.gradle file:

implementation 'com.android.volley:volley:1.0.0'

File ImageFetch.java

Volley requires more setup than Retrofit. You will need to create a class like this to setup a RequestQueue, an ImageLoader and an ImageCache, but it’s not too bad:

public class ImageFetch {
    private static ImageLoader imageLoader = null;
    private static RequestQueue imageQueue = null;

    public static ImageLoader getImageLoader(Context ctx){
        if(imageLoader == null){
            if(imageQueue == null){
                imageQueue = Volley.newRequestQueue(ctx.getApplicationContext());
            }
            imageLoader = new ImageLoader(imageQueue, new ImageLoader.ImageCache() {
                Map<String, Bitmap> cache = new HashMap<String, Bitmap>();
                @Override
                public Bitmap getBitmap(String url) {
                    return cache.get(url);
                }
                @Override
                public void putBitmap(String url, Bitmap bitmap) {
                    cache.put(url, bitmap);
                }
            });
        }
        return imageLoader;
    }
}

File user_view_dialog.xml

Add the following to your layout XML file to add an image:

<com.android.volley.toolbox.NetworkImageView
    android:id="@+id/profile_picture"
    android:layout_width="32dp"
    android:layout_height="32dp"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    app:srcCompat="@android:drawable/spinner_background"/>

File UserViewDialog.java

Add the following code to the onCreate method (Fragment, Activity) or the constructor (Dialog):

NetworkImageView profilePicture = view.findViewById(R.id.profile_picture);
profilePicture.setImageUrl("http://example.com/users/images/profile.jpg", ImageFetch.getImageLoader(getContext());

Picasso

Picasso is another excellent library from Square. Please see the website for some great examples.

While working on some serious project in Android Studio you might’ve happened to come across this nasty error in the above line and all the worlds tried to tear apart. Well, this article has the perfect solution on how to get rid of that ‘android.os.NetworkOnMainThreadException’ error! Read to fix it!

Method #1: The Async Task Way

Believe it or not but when a program tries to perform a networking activity on its main thread, this exception is thrown. Use AsyncTask to run your code. After adopting the async task you could call up the below method to run your task.

GeekTip: Don’t forget to add:
<uses-permission android:name=”android.permission.INTERNET”/>
in your projects manifest file!

Method #2: Overriding the Default Methods

Almost all network actions should be performed in a thread or as an asynchronous task. However, if you are willing to face the penalties, you can remove this restriction and override the default behavior.

Consequences:

Your app will become unresponsive and lock up (in locations with patchy internet connection), the user will sense slowness and will have to forcibly quit the program, and you risk the activity management deleting your app and informing the user that it has stopped.

Method #3: Disabling Strict Mode

We all know what Strict Mode in Android is, and if you are unable to achieve your task, then you can try disabling the Strict Mode in your application. To bypass it, simply go ahead and add this to your NetworkActivity.java.

Method #4: Changing the Worker Thread Manually

If the above methods don’t work out for you, you can manually change the network task to a side thread, and then wait for the result then include it in the main thread, so that the user doesn’t feel sluggish. Add the code below to your NetworkActivity.java file to change the thread.

Reference Article: How Does Threading Work in Android?

Method #5: Using Android Annotations

You can also use the Android Annotations to fix this error and get back going, just add the below code to your Java file and see things move!

And just like adding these simple code snippets could help you get rid of that error forever, and you’re back working on that important project once again!

Last Updated :
13 Sep, 2022

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На этот вопрос уже много замечательных ответов, но с тех пор, как эти ответы были опубликованы, появилось много замечательных библиотек. Это предназначено как своего рода новичок-гид.

Я расскажу о нескольких вариантах использования для выполнения сетевых операций и решения или двух для каждого.

ReST по HTTP

Обычно Json, может быть XML или что-то еще

Полный доступ к API

Скажем, вы пишете приложение, которое позволяет пользователям отслеживать цены акций, процентные ставки и курсовые курсы. Вы найдете Json API, который выглядит примерно так:

http://api.example.com/stocks                       //ResponseWrapper<String> object containing a list of Srings with ticker symbols
http://api.example.com/stocks/$symbol               //Stock object
http://api.example.com/stocks/$symbol/prices        //PriceHistory<Stock> object
http://api.example.com/currencies                   //ResponseWrapper<String> object containing a list of currency abbreviation
http://api.example.com/currencies/$currency         //Currency object
http://api.example.com/currencies/$id1/values/$id2  //PriceHistory<Currency> object comparing the prices of the first currency (id1) to the second (id2)

Модернизация с площади

Это отличный выбор для API с несколькими конечными точками и позволяет объявлять конечные точки REST вместо того, чтобы кодировать их отдельно, как с другими библиотеками, такими как ion или Volley. (веб-сайт: http://square.github.io/retrofit/)

Как вы используете его с API финансов?

build.gradle

Добавьте эти строки на уровень модуля buid.gradle:

implementation 'com.squareup.retrofit2:retrofit:2.3.0' //retrofit library, current as of September 21, 2017
implementation 'com.squareup.retrofit2:converter-gson:2.3.0' //gson serialization and deserialization support for retrofit, version must match retrofit version

FinancesApi.java

public interface FinancesApi {
    @GET("stocks")
    Call<ResponseWrapper<String>> listStocks();
    @GET("stocks/{symbol}")
    Call<Stock> getStock(@Path("symbol")String tickerSymbol);
    @GET("stocks/{symbol}/prices")
    Call<PriceHistory<Stock>> getPriceHistory(@Path("symbol")String tickerSymbol);

    @GET("currencies")
    Call<ResponseWrapper<String>> listCurrencies();
    @GET("currencies/{symbol}")
    Call<Currency> getCurrency(@Path("symbol")String currencySymbol);
    @GET("currencies/{symbol}/values/{compare_symbol}")
    Call<PriceHistory<Currency>> getComparativeHistory(@Path("symbol")String currency, @Path("compare_symbol")String currencyToPriceAgainst);
}

FinancesApiBuilder

public class FinancesApiBuilder {
    public static FinancesApi build(String baseUrl){
        return new Retrofit.Builder()
                    .baseUrl(baseUrl)
                    .addConverterFactory(GsonConverterFactory.create())
                    .build()
                    .create(FinancesApi.class);
    }
}

Фундамент Фрагмент

FinancesApi api = FinancesApiBuilder.build("http://api.example.com/"); //trailing '/' required for predictable behavior
api.getStock("INTC").enqueue(new Callback<Stock>(){
    @Override
    public void onResponse(Call<Stock> stockCall, Response<Stock> stockResponse){
        Stock stock = stockCall.body();
        //do something with the stock
    }
    @Override
    public void onResponse(Call<Stock> stockCall, Throwable t){
        //something bad happened
    }
}

Если вашему API требуется ключ API или другой заголовок, такой как токен пользователя и т.д., Retrofit делает это проще (подробнее см. Этот удивительный ответ: https://stackoverflow.com/questions/42898920/add-header-parameter-in-retrofit).

Один доступ к API-интерфейсу ReST

Скажем, вы создаете приложение “погода в настроении”, которое просматривает местоположение GPS-пользователей и проверяет текущую температуру в этой области и сообщает им настроение. Для этого типа приложения не требуется объявлять конечные точки API; ему просто нужно иметь доступ к одной конечной точке API.

ион

Это отличная библиотека для такого типа доступа.

Пожалуйста, прочитайте msysmilu отличный ответ (https://stackoverflow.com/questions/6343166/how-do-i-fix-android-os-networkonmainthreadexception)

Загружать изображения через HTTP

залп

Volley также может использоваться для API-интерфейсов ReST, но из-за более сложной настройки я предпочитаю использовать Retrofit from Square, как указано выше (http://square.github.io/retrofit/)

Скажем, вы строите приложение для социальных сетей и хотите загружать фотографии друзей друзей.

build.gradle

Добавьте эту строку в свой уровень модуля buid.gradle:

implementation 'com.android.volley:volley:1.0.0'

ImageFetch.java

Volley требует больше настроек, чем дооснащение. Вам нужно будет создать такой класс, чтобы настроить RequestQueue, ImageLoader и ImageCache, но это не так уж плохо:

public class ImageFetch {
    private static ImageLoader imageLoader = null;
    private static RequestQueue imageQueue = null;

    public static ImageLoader getImageLoader(Context ctx){
        if(imageLoader == null){
            if(imageQueue == null){
                imageQueue = Volley.newRequestQueue(ctx.getApplicationContext());
            }
            imageLoader = new ImageLoader(imageQueue, new ImageLoader.ImageCache() {
                Map<String, Bitmap> cache = new HashMap<String, Bitmap>();
                @Override
                public Bitmap getBitmap(String url) {
                    return cache.get(url);
                }
                @Override
                public void putBitmap(String url, Bitmap bitmap) {
                    cache.put(url, bitmap);
                }
            });
        }
        return imageLoader;
    }
}

user_view_dialog.xml

Добавьте следующее в свой XML файл макета, чтобы добавить изображение:

<com.android.volley.toolbox.NetworkImageView
    android:id="@+id/profile_picture"
    android:layout_width="32dp"
    android:layout_height="32dp"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    app:srcCompat="@android:drawable/spinner_background"/>

UserViewDialog.java

Добавьте следующий код в метод onCreate (Fragment, Activity) или конструктор (Dialog):

NetworkImageView profilePicture = view.findViewById(R.id.profile_picture);
profilePicture.setImageUrl("http://example.com/users/images/profile.jpg", ImageFetch.getImageLoader(getContext());

Пикассо

Еще одна отличная библиотека с площади. Пожалуйста, посетите сайт для некоторых замечательных примеров: http://square.github.io/picasso/

Code:

URL url = new URL(urlToRssFeed);
SAXParserFactory factory = SAXParserFactory.newInstance();
SAXParser parser = factory.newSAXParser();
XMLReader xmlreader = parser.getXMLReader();
RssHandler theRSSHandler = new RssHandler();
xmlreader.setContentHandler(theRSSHandler);
InputSource is = new InputSource(url.openStream());
xmlreader.parse(is);
return theRSSHandler.getFeed();

android.os.NetworkOnMainThreadException

class RetrieveFeedTask extends AsyncTask<String, Void, RSSFeed> {

    private Exception exception;

    protected RSSFeed doInBackground(String... urls) {
        try {
            URL url = new URL(urls[0]);
            SAXParserFactory factory = SAXParserFactory.newInstance();
            SAXParser parser = factory.newSAXParser();	
            XMLReader xmlreader = parser.getXMLReader();
            RssHandler theRSSHandler = new RssHandler();
            xmlreader.setContentHandler(theRSSHandler);
            InputSource is = new InputSource(url.openStream());
            xmlreader.parse(is);

            return theRSSHandler.getFeed();
        } catch (Exception e) {
            this.exception = e;

            return null;
        }
    }

    protected void onPostExecute(RSSFeed feed) {
        // TODO: check this.exception
        // TODO: do something with the feed
    }
}

How to execute the task:

In MainActivity.java file we can add this line within the oncreate() method

new RetrieveFeedTask().execute(urlToRssFeed);

<uses-permission android:name="android.permission.INTERNET"/>

Add:

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();

StrictMode.setThreadPolicy(policy); 

<uses-permission android:name="android.permission.INTERNET"/>

Consequences:

Thread thread = new Thread(new Runnable() {

    @Override
    public void run() {
        try  {
            //Your code goes here
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
});

thread.start(); 

Use Service or AsyncTask