I have this little piece of code and I want to achieve this: program should set a wallpaper from linked image.
ImgDownload:
public class ImgDownload extends AsyncTask {
private String requestUrl;
private ImageView view;
private Bitmap pic;
private ImgDownload(String requestUrl, ImageView view) {
this.requestUrl = requestUrl;
this.view = view;
}
#Override
protected Object doInBackground(Object... objects) {
try {
URL url = new URL(requestUrl);
URLConnection conn = url.openConnection();
pic = BitmapFactory.decodeStream(conn.getInputStream());
} catch (Exception ex) {
}
return null;
}
#Override
protected void onPostExecute(Object o) {
view.setImageBitmap(pic);
}
}
main
public class MainActivity extends Activity {
private ImageView img;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
img= (ImageView)findViewById(R.id.img);
//!!!! This is where I am stuck :)
Object s = new ImgDownload("http://images1.wikia.nocookie.net/__cb20120402213849/masseffect/images/4/42/Uncharted_Worlds_Codex_Image.jpg",img );
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
How to instantiate/create this class in my mainActivity, so it could download img from link? Any help suggestions, thoughts, will be appreciated :)
You execute this AsyncTask like this:
ImgDownload downloader = new ImgDownload("http://images1.wikia.nocookie.net/__cb20120402213849/masseffect/images/4/42/Uncharted_Worlds_Codex_Image.jpg",img);
downloader.execute();
But I would not recommend using your code as it will produce memory leaks. For example try to rotate your device while it is downloading an image. I guarantee you your application will crash. Plus AsyncTask is a generic class. You could use that to make your code a little simpler. Here is my improved image download task:
public class ImgDownload extends AsyncTask<Void, Void, Bitmap> { // Use Generics
private final String requestUrl;
private final WeakReference<ImageView> imageViewReference; // Use WeakReference to prevent memory leaks
public ImgDownload(String requestUrl, ImageView view) {
this.requestUrl = requestUrl;
this.imageViewReference = new WeakReference<ImageView>(view);
}
#Override
protected Bitmap doInBackground(Void... objects) {
try {
URL url = new URL(requestUrl);
URLConnection conn = url.openConnection();
return BitmapFactory.decodeStream(conn.getInputStream()); // Return bitmap instead of using global variable
} catch (Exception ex) {
}
return null;
}
#Override
protected void onPostExecute(Bitmap bitmap) {
ImageView imageView = imageViewReference.get();
if(imageView != null && bitmap != null) { // Check if image or ImageView are null
imageView.setImageBitmap(bitmap);
}
}
}
new ImgDownload("http://images1.wikia.nocookie.net/__cb20120402213849/masseffect/images/4/42/Uncharted_Worlds_Codex_Image.jpg", MainActivity.img).execute();
Related
I'm trying receive the image over TCP (in Asynctask) and display it in ImageView but I have an error in onPostExecute. Anyone know why?
And also whether idea of receiving is correct, if the next step will be recurring receiving image over TCP and displaying it?
Code:
public class TcpClient extends Activity {
ImageView imageView;
public static String aHost;
public String aSocketIn;
public static int aSocketInInt;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.bundle_result);
imageView = (ImageView) findViewById(R.id.imageView);
Intent intent = getIntent();
aHost = intent.getStringExtra("addressIp");
aSocketIn = intent.getStringExtra("socketIn");
aSocketInInt = Integer.parseInt(aSocketIn);
new DownloadImageTask(aHost,aSocketInInt).execute();
} }
public class DownloadImageTask extends AsyncTask <Void,Void,Bitmap > {
public Bitmap bitmap = null;
String Host;
int SocketIn;
public DownloadImageTask(String Host,int SocketIn) {
this.Host = Host;
this.SocketIn = SocketIn;
}
#Override
protected Bitmap doInBackground(Void... params) {
ClientIn clientIn;
try {
InetAddress serwerAddress = InetAddress.getByName(Host);
Socket socket = new Socket(serwerAddress, SocketIn);
clientIn = new ClientIn(socket);
bitmap = clientIn.Receive();
return bitmap;
}
catch (Exception e) {
e.printStackTrace();
return null;
}
}
#Override
protected void onPostExecute(Bitmap result) {
imageView.setImageBitmap(result); // ERROR: Cannot resolve symbol 'imageView'
} }
Looks like DownloadImageTask class is not inner-class of TcpClient class which is extending Activity,so to access imageView object of ImageView in other class, need to send it on DownloadImageTask using class constructor in same way as doing currently for getting Host and SocketIn in DownloadImageTask class.
Change DownloadImageTask as for to using imageView "
public DownloadImageTask(String Host,int SocketIn,ImageView imageView) {
this.Host = Host;
this.SocketIn = SocketIn;
this.imageView=imageView;
}
My code is :
public class MainActivity extends ActionBarActivity {
String URL1 = "http://cs619925.vk.me/v619925510/1b82b/0nTm-Pj0ABM.jpg";
String URL2 = "http://8tracks.imgix.net/i/000/955/740/87318.original-8382.jpg?rect=128,0,768,768&q=65&sharp=15&vib=10&fm=jpg&fit=max&w=200&h=200";
String URL3 = "http://a400.idata.over-blog.com/300x225/1/89/70/64/Autres-images/smiley-face-on-beach.jpg";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView myFirstImage = (ImageView) findViewById(R.id.iv1);
ImageView mySecondImage = (ImageView) findViewById(R.id.iv2);
ImageView myThirdImage = (ImageView) findViewById(R.id.iv3);
myFirstImage.setTag(URL1);
mySecondImage.setTag(URL2);
myThirdImage.setTag(URL3);
new DownloadImagesTask().execute(myFirstImage);
new DownloadImagesTask().execute(mySecondImage);
new DownloadImagesTask().execute(myThirdImage);
}
public class DownloadImagesTask extends AsyncTask<ImageView, Void, Bitmap> {
ImageView imageView = null;
protected Bitmap doInBackground(ImageView... imageViews) {
this.imageView = imageViews[0];
return download_Image((String)imageView.getTag());
}
protected void onPostExecute(Bitmap result) {
imageView.setImageBitmap(result);
}
private Bitmap download_Image(String url) {
Bitmap bmp =null;
try{
URL ulrn = new URL(url);
HttpURLConnection con = (HttpURLConnection)ulrn.openConnection();
InputStream is = con.getInputStream();
bmp = BitmapFactory.decodeStream(is);
if (null != bmp)
return bmp;
}catch(Exception e){}
return bmp;
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
On running it on the emulator, I don't get images displayed. Help me with this one.And I don't even know what the eroor is? if there is any.
if you want download file or if you want load image into imageview, then
use picasso:
Picasso.with(context).load(URL1).into(myFirstImage);
public class MainActivity extends ActionBarActivity {
String URL1 = "http://cs619925.vk.me/v619925510/1b82b/0nTm-Pj0ABM.jpg";
String URL2 = "http://8tracks.imgix.net/i/000/955/740/87318.original-8382.jpg?rect=128,0,768,768&q=65&sharp=15&vib=10&fm=jpg&fit=max&w=200&h=200";
String URL3 = "http://a400.idata.over-blog.com/300x225/1/89/70/64/Autres-images/smiley-face-on-beach.jpg";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageView myFirstImage = (ImageView) findViewById(R.id.iv1);
ImageView mySecondImage = (ImageView) findViewById(R.id.iv2);
ImageView myThirdImage = (ImageView) findViewById(R.id.iv3);
Picasso.with(this).load(URL1).into(myFirstImage);
Picasso.with(this).load(URL2).into(mySecondImage);
Picasso.with(this).load(URL3).into(myThirdImage);
}
}
You can easily download image using Picasso and Glide library.
I'm trying to load images with an async taks from internet. The problem is that the image will not update. Code:
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i ;
i = new ImageView(this.mContext);
AsycTask task = new AsycTask();
task.url = new URL(mImageIds.get(position));
task.iv = i;
task.execute(i);
return i;
}
public class AsycTask extends AsyncTask<ImageView, Void, Bitmap>{
public Bitmap bm2;
public ImageView iv;
public URL url;
#Override
protected Bitmap doInBackground(ImageView... arg0) {
iv = arg0[0];
try {
bm2 = BitmapFactory.decodeStream((InputStream)url.getContent());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return bm2;
}
#Override
protected void onPostExecute(Bitmap result) {
// iv.setImageResource(R.drawable.sw10)
iv.setVisibility(View.VISIBLE);
iv.setBackgroundResource(R.drawable.search);
iv.setScaleType(ImageView.ScaleType.FIT_XY);
iv.setImageBitmap(result);
}
#Override
protected void onPreExecute() {
}
#Override
protected void onProgressUpdate(Void... values) {
}
}
Why isn't the Image updating after I set the Bitmap?
I'm using an async task to update my Image, is this possible?
Try to use UnivsersalImageLoader lib which will simplify your development.
Your code for image loading will be next:
ImageLoader.getInstance().displayImage(imageUrl, imageView); // Default options will be used
UniversalImageLoader
I've been having problems with this for quite some time now. I'm getting there little by little but I don't have much time to spend programming :(
So I'm having to load image from URLs for showing on a list view, and i'm almost there. They are lazy loading and the cache system i'm using works good.
The problem is that the downloaded images are in the wrong place when I start scrolling and I can't figure out where i'm going wrong.
The code is inspired from these two links:
This one for the layout idea.
http://blog.blundell-apps.com/imageview-with-loading-spinner/
and this one for the cache system.
http://android-developers.blogspot.fr/2010/07/multithreading-for-performance.html
So here's my code:
public class LoaderImageView extends LinearLayout
{
private static final String TAG = "LoderImageView";
private Context mContext;
private ImageView mImage;
private ProgressBar mSpinner;
/* The HashMap that contains the references to the different
* downloads currently running.
*/
public static HashMap<LoaderImageView, BitmapDownloaderTask> tasks =
new LinkedHashMap<LoaderImageView, BitmapDownloaderTask>();
public LoaderImageView(Context context, AttributeSet attrs)
{
super(context, attrs);
mContext = context;
mImage = new ImageView(mContext);
mImage.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
mSpinner = new ProgressBar(mContext);
mSpinner.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
mSpinner.setIndeterminate(true);
addView(mSpinner);
addView(mImage);
Log.w(TAG, "Loading an imageView");
}
public void downloadImage(String url)
{
resetPurgeTimer();
//Log.w(TAG, "Loading: " + url);
if(url.equals(""))
{
mImage.setImageDrawable(mContext.getResources().getDrawable(R.drawable.male));
}
else
{
Bitmap bitmap = getBitmapFromCache(url);
if(bitmap == null)
{
/* The bitmap is not in the cache. */
cancelPotentialDownload(this);
/* Start the new download. */
BitmapDownloaderTask bdt = new BitmapDownloaderTask(this, url);
bdt.execute();
}
else
{
/*The bitmap is in the cache. */
mImage.setImageBitmap(bitmap);
mSpinner.setVisibility(View.GONE);
}
}
}
class BitmapDownloaderTask extends AsyncTask<Void, Void, Bitmap>
{
private String mUrl;
private LoaderImageView mLiv;
public BitmapDownloaderTask(LoaderImageView liv, String url)
{
mLiv = liv;
mUrl = url;
}
#Override
protected void onPreExecute()
{
LoaderImageView.tasks.put(mLiv, this);
mSpinner.setVisibility(View.VISIBLE);
mImage.setVisibility(View.GONE);
Log.w(TAG, "Starting an AsyncTask");
}
#Override
protected Bitmap doInBackground(Void... voids)
{
URL url = null;
try
{
url = new URL(mUrl);
}
catch (MalformedURLException e)
{
e.printStackTrace();
}
return BitmapTools.fetchBitmap(url);
}
#Override
protected void onPostExecute(Bitmap bitmap)
{
BitmapDownloaderTask b = tasks.get(mLiv);
if(b == this)
{
LoaderImageView.tasks.remove(this);
mImage.setImageBitmap(bitmap);
}
if (isCancelled())
{
bitmap = null;
}
addBitmapToCache(mUrl, bitmap);
tasks.remove(mLiv);
mSpinner.setVisibility(View.GONE);
mImage.setVisibility(View.VISIBLE);
}
}
/* More methods related too the cache... */
Here the xml layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="60dp"
android:background="#drawable/list_item_selector" >
<com.myproject.liste.LoaderImageView
android:id="#+id/visites_image"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true" />
</RelativeLayout>
I'm creating the list with a BaseAdapter and ListActivity.
Also i'm loading the list by pages of data: I load 10 items, when the user scrolls down I load 10 more, and call notifyDataSetChange();
i have this class:
public class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
ImageFromWeb ifw;
private String url;
private final WeakReference<ImageView> imageViewReference;
public DownloadImageTask(ImageView imageView) {
imageViewReference = new WeakReference<ImageView>(imageView);
}
#Override
protected Bitmap doInBackground(String... params) {
url = params[0];
try {
return BitmapFactory.decodeStream(new URL(url).openConnection().getInputStream());
} catch (MalformedURLException e) {
e.printStackTrace();
return null;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
#Override
protected void onPostExecute(Bitmap result) {
if (isCancelled()) {
result = null;
}
if (imageViewReference != null) {
ImageView imageView = imageViewReference.get();
if (imageView != null) {
imageView.setImageBitmap(result);
}
}
}
#Override
protected void onPreExecute() {
if (imageViewReference != null) {
ImageView imageView = imageViewReference.get();
if (imageView != null) {
---------> imageView.setImageResource(R.drawable.pw);
}
}
}
}
and the main activity:
public class ImageFromWeb extends Activity {
private String path = "http://....";
private ImageView imageView;
public void onCreate(Bundle bundle) {
super.onCreate(bundle);
setContentView(R.layout.main);
ImageView mChart = (ImageView) findViewById(R.id.imview);
mChart.setTag(path);
new DownloadImageTask(mChart).execute(path);
}
}
I want to put in the point of arrow(in DownloadImageTask class) an alert dialog! How can i do this? Because this class isn't an activity.
thanks :)
change the constructor and pass a Context object
Context mContext;
public DownloadImageTask(ImageView imageView,Context mContext) {
imageViewReference = new WeakReference<ImageView>(imageView);
this.mContext = mContext;
}
Now you can use this Context to create dialogs
You can even cast mContext to your Activity class and call functions within your Activity
Move the Async Task to your activity and use that to call your DownloadImageTask class & methods. This will make your life a lot easier.
pass a Activity instance to the class where you want to display dialog, and check
if(!actvity.isFinishing){
//show dialog
}
You can have a static Context in your Application like this:
public static Context CurrentContext;
and a custom abstract Activity that sets currentContext upon creation like this:
public abstract class CustomActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
MyApplication.CurrentContext = this;
}
}
Then you would get context like this:
AlertDialog.Builder dlgBuilder = new AlertDialog.Builder(MyApplication.CurrentContext);
dlgBuilder.setTitle("Context Example");
dlgBuilder.setMessage("I am being shown from the application Static context!");
dlgBuilder.setNeutralButton("Ok", null);
dlgBuilder.show();
This way you never have to worry about context wether you are in a background task or directly in an Activity it will work for most cases.
hope this helps!