java - resource - imageview bitmap android

Carga de Android desde la URL al mapa de bits

Question

Tengo una pregunta sobre cómo cargar una imagen desde un sitio web. El código que uso es:

Display display = getWindowManager().getDefaultDisplay();
int width = display.getWidth();
int height = display.getHeight();
Bitmap bit=null;
try {
bit = BitmapFactory.decodeStream((InputStream)new URL("http://www.mac-wallpapers.com/bulkupload/wallpapers/Apple%20Wallpapers/apple-black-logo-wallpaper.jpg").getContent());
} catch (Exception e) {}
Bitmap sc = Bitmap.createScaledBitmap(bit,width,height,true);
canvas.drawBitmap(sc,0,0,null);

Pero siempre devuelve una excepción de puntero nulo y el programa falla. La URL es válida y parece funcionar para todos los demás. Estoy usando 2.3.1.

Answer 1

De manera muy rápida, este método funciona muy rápido:

private Bitmap getBitmap(String url)
{
File f=fileCache.getFile(url);
//from SD cache
Bitmap b = decodeFile(f);
if(b!=null)
return b;
//from web
try {
Bitmap bitmap=null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection();
conn.setConnectTimeout(30000);
conn.setReadTimeout(30000);
conn.setInstanceFollowRedirects(true);
InputStream is=conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
bitmap = decodeFile(f);
return bitmap;
} catch (Exception ex){
ex.printStackTrace();
return null;
}
}
//decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f){
try {
//decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f),null,o);
//Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE=70;
int width_tmp=o.outWidth, height_tmp=o.outHeight;
int scale=1;
while(true){
if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
break;
width_tmp/=2;
height_tmp/=2;
scale*=2;
}
//decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize=scale;
return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
} catch (FileNotFoundException e) {}
return null;
}

Answer 2

Pase su URL de imagen: intente esto:

private Bitmap getBitmap(String url)
{
File file=fileCache.getFile(url);
Bitmap bm = decodeFile(file);
if(bm!=null)
return bm;
try {
Bitmap bitmap=null;
URL ImageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection)ImageUrl.openConnection();
conn.setConnectTimeout(50000);
conn.setReadTimeout(50000);
conn.setInstanceFollowRedirects(true);
InputStream is = conn.getInputStream();
OutputStream os = new FileOutputStream(file);
Utils.CopyStream(is, os);
os.close();
bitmap = decodeFile(file);
return bitmap;
} catch (Exception ex){
ex.printStackTrace();
return null;
}
}
private Bitmap decodeFile(File file){
try {
BitmapFactory.Options opt = new BitmapFactory.Options();
opt.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(file),null,opt);
final int REQUIRED_SIZE=70;
int width_tmp=opt.outWidth, height_tmp=opt.outHeight;
int scale=1;
while(true){
if(width_tmp/2<REQUIRED_SIZE || height_tmp/2<REQUIRED_SIZE)
break;
width_tmp/=2;
height_tmp/=2;
scale*=2;
}
BitmapFactory.Options opte = new BitmapFactory.Options();
opte.inSampleSize=scale;
return BitmapFactory.decodeStream(new FileInputStream(file), null, opte);
} catch (FileNotFoundException e) {}
return null;
}

Crear Utilidades de Clase:

public class Utils {
public static void CopyStream(InputStream is, OutputStream os)
{
final int buffer_size=1024;
try
{
byte[] bytes=new byte[buffer_size];
for(;;)
{
int count=is.read(bytes, 0, buffer_size);
if(count==-1)
break;
os.write(bytes, 0, count);
}
}
catch(Exception ex){}
}
}

Answer 3

Por favor, intente estos siguientes pasos.

1) Cree AsyncTask en clase o adaptador (si desea cambiar la imagen del elemento de la lista).

public class AsyncTaskLoadImage extends AsyncTask<String, String, Bitmap> {
private final static String TAG = "AsyncTaskLoadImage";
private ImageView imageView;
public AsyncTaskLoadImage(ImageView imageView) {
this.imageView = imageView;
}
@Override
protected Bitmap doInBackground(String... params) {
Bitmap bitmap = null;
try {
URL url = new URL(params[0]);
bitmap = BitmapFactory.decodeStream((InputStream) url.getContent());
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return bitmap;
}
@Override
protected void onPostExecute(Bitmap bitmap) {
try {
int width, height;
height = bitmap.getHeight();
width = bitmap.getWidth();
Bitmap bmpGrayscale = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bmpGrayscale);
Paint paint = new Paint();
ColorMatrix cm = new ColorMatrix();
cm.setSaturation(0);
ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
paint.setColorFilter(f);
c.drawBitmap(bitmap, 0, 0, paint);
imageView.setImageBitmap(bmpGrayscale);
} catch (Exception e) {
e.printStackTrace();
}
}
}

2) Llame a AsyncTask desde su actividad, fragmento o adaptador (dentro deBindViewHolder).

2.a) Para el adaptador:

 String src = current.getProductImage();
new AsyncTaskLoadImage(holder.icon).execute(src);

2.b) Para actividad y fragmento:

**Activity:**
ImageView imagview= (ImageView) findViewById(R.Id.imageview);
String src = (your image string);
new AsyncTaskLoadImage(imagview).execute(src);
**Fragment:**
ImageView imagview= (ImageView)view.findViewById(R.Id.imageview);
String src = (your image string);
new AsyncTaskLoadImage(imagview).execute(src);

3) Por favor, ejecute la aplicación y verifique la imagen.

Feliz codificación ... :)

Answer 4

Prueba esto:

AQuery aq = new AQuery(getActivity());
aq.id(view.findViewById(R.id.image)).image(imageUrl, true, true, 0, 0,
new BitmapAjaxCallback() {
@Override
public void callback(String url, ImageView iv, Bitmap bm, AjaxStatus status){
iv.setImageBitmap(bm);
}
}.header("User-Agent", "android"));

Answer 5

Si carga URL desde mapa de bits sin utilizar AsyncTask, escriba dos líneas después de setContentView (R.layout.abc);

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
try {
URL url = new URL("http://....");
Bitmap image = BitmapFactory.decodeStream(url.openConnection().getInputStream());
} catch(IOException e) {
System.out.println(e);
}

Answer 6

Si está usando Picasso o Universal-Image-Loader para cargar imágenes desde url.
Simplemente puede obtener el mapa de bits cargado por

Para Picasso

Picasso.with(this)
.load(imageUrl)
.into(new Target() {
@Override
public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
// loaded bitmap is here (bitmap)
}
@Override
public void onBitmapFailed(Drawable errorDrawable) {
}
@Override
public void onPrepareLoad(Drawable placeHolderDrawable) {
}
});

Para Universal-Image-Loader

imageLoader.loadImage(imageUrl, new SimpleImageLoadingListener()
{
@Override
public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage)
{
// loaded bitmap is here (loadedImage)
}
});

Answer 7

Si está usando Picasso para imágenes, puede probar el método a continuación.

public static Bitmap getImageBitmapFromURL(Context context, String imageUrl){
Bitmap imageBitmap = null;
try {
imageBitmap = new AsyncTask<Void, Void, Bitmap>() {
@Override
protected Bitmap doInBackground(Void... params) {
try {
int targetHeight = 200;
int targetWidth = 200;
return Picasso.with(context).load(String.valueOf(imageUrl))
//.resize(targetWidth, targetHeight)
.placeholder(R.drawable.raw_image)
.error(R.drawable.raw_error_image)
.get();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
}.execute().get();
} catch (InterruptedException e) {
e.printStackTrace();
}
return imageBitmap;
}

Answer 8

Siga el método para obtener la URL en el mapa de bits en Android, simplemente pase el enlace de esta imagen y obtenga un mapa de bits.

public static Bitmap getBitmapFromURL(String imgUrl) {
try {
URL url = new URL(imgUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
Bitmap myBitmap = BitmapFactory.decodeStream(input);
return myBitmap;
} catch (IOException e) {
// Log exception
return null;
}
}

Answer 9

Yo prefiero estos:

Crea Bitmap de InputStream y lo devuelve:

 public static Bitmap downloadImage(String url) {
Bitmap bitmap = null;
InputStream stream = null;
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inSampleSize = 1;
try {
stream = getHttpConnection(url);
bitmap = BitmapFactory.decodeStream(stream, null, bmOptions);
stream.close();
}
catch (IOException e1) {
e1.printStackTrace();
System.out.println("downloadImage"+ e1.toString());
}
return bitmap;
}
// Makes HttpURLConnection and returns InputStream
public static InputStream getHttpConnection(String urlString) throws IOException {
InputStream stream = null;
URL url = new URL(urlString);
URLConnection connection = url.openConnection();
try {
HttpURLConnection httpConnection = (HttpURLConnection) connection;
httpConnection.setRequestMethod("GET");
httpConnection.connect();
if (httpConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
stream = httpConnection.getInputStream();
}
}
catch (Exception ex) {
ex.printStackTrace();
System.out.println("downloadImage" + ex.toString());
}
return stream;
}

RECUERDA :

Android incluye dos clientes HTTP : HttpURLConnection y Apache HTTP Client. Para Gingerbread y más tarde, HttpURLConnection es la mejor opción.

Desde Android 3.x Honeycomb o posterior, no puede realizar Network IO en el hilo de la interfaz de usuario y hacer esto arroja android.os.NetworkOnMainThreadException . Debe usar Asynctask en su lugar como se muestra a continuación

/** AsyncTAsk for Image Bitmap */
private class AsyncGettingBitmapFromUrl extends AsyncTask<String, Void, Bitmap> {
@Override
protected Bitmap doInBackground(String... params) {
System.out.println("doInBackground");
Bitmap bitmap = null;
bitmap = AppMethods.downloadImage(params[0]);
return bitmap;
}
@Override
protected void onPostExecute(Bitmap bitmap) {
System.out.println("bitmap" + bitmap);
}
}

Answer 10

Glide.with(context)
.load("http://test.com/yourimage.jpg")
.asBitmap() // переводим его в нужный формат
.fitCenter()
.into(new SimpleTarget<Bitmap>(100,100) {
@Override
public void onResourceReady(Bitmap bitmap, GlideAnimation<? super Bitmap> glideAnimation) {
// do something with you bitmap
bitmap
}
});

Answer 11

public Drawable loadImageFromURL(String url, String name) {
try {
InputStream is = (InputStream) new URL(url).getContent();
Drawable d = Drawable.createFromStream(is, name);
return d;
} catch (Exception e) {
return null;
}
}

Answer 12

public static Bitmap getBitmapFromURL(String src) {
try {
URL url = new URL(src);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.connect();
InputStream input = connection.getInputStream();
Bitmap myBitmap = BitmapFactory.decodeStream(input);
return myBitmap;
} catch (IOException e) {
// Log exception
return null;
}
}

Answer 13

public static Bitmap getImgBitmapFromUri(final String url, final Activity context, final CropImageView imageView, final File file) {
final Bitmap bitmap = null;
AsyncTask.execute(new Runnable() {
@Override
public void run() {
try {
Utils.image = Glide.with(context)
.load(url).asBitmap()
.into(100, 100).get();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
context.runOnUiThread(new Runnable() {
@Override
public void run() {
if (imageView != null)
imageView.setImageBitmap(Utils.image);
}
});
}
});
return Utils.image;
}

Use la biblioteca Glide y ejecute el siguiente código en el hilo de trabajo como se publicó