Re: [androidbrasil-dev] Erro ao exibir imagem da WEB

Brigadão Rodrigo,

O conhecimento q vc passou foi fundamental(aprendi muito com sua explicação), porem tive q dar uma adequadinha basica...

Nessa linha a classe precisa extender da activity

            ImageView imgView =(ImageView)findViewById(R.id.teste);

Então fiz assim:

public class LoadImageTask extends AsyncTask <String, Void, Drawable> {  	ProgressDialog progress;  	private WeakReference<ImageView> imageViewReference;  	  	public LoadImageTask(ImageView imageView) {          imageViewReference = new WeakReference<ImageView>(imageView);      }    	@Override  	 protected Drawable doInBackground(String... url) {             Drawable drawable = null;             try {  			drawable = LoadImageFromWebOperations(url[0]);  		} catch (MalformedURLException e) {  			// TODO Auto-generated catch block  			e.printStackTrace();  		} catch (IOException e) {  			// TODO Auto-generated catch block  			e.printStackTrace();  		}           return drawable;       }  	  	 private Drawable LoadImageFromWebOperations(String url) throws MalformedURLException, IOException {  	    	  	    	InputStream is = (InputStream) new URL(url).getContent();  	        Drawable d = Drawable.createFromStream(is, "src name");  	        return d;    	    }  	   	protected void onPostExecute(Drawable drawable) {  		imageViewReference.get().setImageDrawable(drawable);       }  }

E na chamada passei o objeto ImageView:

LoadImageTask task = new LoadImageTask(imageView);  task.execute(url);

Em sexta-feira, 28 de junho de 2013 19h36min38s UTC-3, Rodrigo Piovezan escreveu:

Olá Vinny,

Essa exception ocorre porque você está tentando realizar uma operação de acesso à rede dentro da thread principal, que é reservada para operações de UI (user interface). Faça essa operação em uma thread separada, por exemplo usando uma AsyncTask (que executa o que estiver dentro do método doInBackground() numa thread à parte):

class LoadImageTask extends AsyncTask<String, Void, Drawable> {

        protected Drawable doInBackground(String... url) {
            Drawable drawable = null;
              try {
                drawable = LoadImageFromWebOperations(url[0]);
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                  e.printStackTrace();
              }
            return drawable;
        }

        protected void onPostExecute(Drawable drawable) {
            ImageView imgView =(ImageView)findViewById(R.id.teste);
            imgView.setImageDrawable(drawable);
            }
}

O que está acontecendo é que a asynctask espera o método doInBackground() executar, e quando ele termina passa a ser executado o método onPostExecute(), que volta a ter acesso à thread de UI e pode executar operações de UI, como por exemplo chamar setImageDrawable() para exibir o drawable.

Para chamar a asynctask no seu código você faz assim:

LoadImageTask task = new LoadImageTask();
task.execute("http://marciocardoso.net/img/Linux_avatar.jpg");
    

[]'s

Rodrigo

On Fri, Jun 28, 2013 at 4:57 PM, Vinny Valente <irmaoca...@gmail.com> wrote:

Boa tarde Galera,

Estou tentando exibir uma imagem da web, mas ta complicado.

Todas as formas que eu li caem na mesmo esquema, justamente onde da o erro...

Nessa linha 

InputStream is = (InputStream) new URL(url).getContent();

O getContent() sempre cai na exeption...

Segue erro

06-28 16:29:00.450: E/AndroidRuntime(14548): FATAL EXCEPTION: main

06-28 16:29:00.450: E/AndroidRuntime(14548): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.slideshow/com.example.slideshow.MainActivity}: android.os.NetworkOnMainThreadException

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2100)

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2125)

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.app.ActivityThread.access$600(ActivityThread.java:140)

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1227)

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.os.Handler.dispatchMessage(Handler.java:99)

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.os.Looper.loop(Looper.java:137)

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.app.ActivityThread.main(ActivityThread.java:4898)

06-28 16:29:00.450: E/AndroidRuntime(14548): at java.lang.reflect.Method.invokeNative(Native Method)

06-28 16:29:00.450: E/AndroidRuntime(14548): at java.lang.reflect.Method.invoke(Method.java:511)

06-28 16:29:00.450: E/AndroidRuntime(14548): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1006)

06-28 16:29:00.450: E/AndroidRuntime(14548): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:773)

06-28 16:29:00.450: E/AndroidRuntime(14548): at dalvik.system.NativeStart.main(Native Method)

06-28 16:29:00.450: E/AndroidRuntime(14548): Caused by: android.os.NetworkOnMainThreadException

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1118)

06-28 16:29:00.450: E/AndroidRuntime(14548): at java.net.InetAddress.lookupHostByName(InetAddress.java:385)

06-28 16:29:00.450: E/AndroidRuntime(14548): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)

06-28 16:29:00.450: E/AndroidRuntime(14548): at java.net.InetAddress.getAllByName(InetAddress.java:214)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:315)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpEngine.connect(HttpEngine.java:310)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:289)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:239)

06-28 16:29:00.450: E/AndroidRuntime(14548): at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:80)

06-28 16:29:00.450: E/AndroidRuntime(14548): at java.net.URLConnection.getContent(URLConnection.java:190)

06-28 16:29:00.450: E/AndroidRuntime(14548): at java.net.URL.getContent(URL.java:447)

06-28 16:29:00.450: E/AndroidRuntime(14548): at com.example.slideshow.MainActivity.LoadImageFromWebOperations(MainActivity.java:114)

06-28 16:29:00.450: E/AndroidRuntime(14548): at com.example.slideshow.MainActivity.onCreate(MainActivity.java:38)

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.app.Activity.performCreate(Activity.java:5206)

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1083)

06-28 16:29:00.450: E/AndroidRuntime(14548): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2064)

06-28 16:29:00.450: E/AndroidRuntime(14548): ... 11 more

Codigo:

ImageView imgView =(ImageView)findViewById(R.id.teste);

        Drawable drawable = null;

try {

drawable = LoadImageFromWebOperations("http://marciocardoso.net/img/Linux_avatar.jpg");

} catch (MalformedURLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

        imgView.setImageDrawable(drawable);

 private Drawable LoadImageFromWebOperations(String url) throws MalformedURLException, IOException {

   

    InputStream is = (InputStream) new URL(url).getContent();

        Drawable d = Drawable.createFromStream(is, "src name");

        return d;

    }

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