I want to set a TextView with SpannableString which is from the method below:
Html.fromHtml(String source, Html.ImageGetter imageGetter,
Html.TagHandler tagHandler)
But the ImageGetter here need to override the method below:
public abstract Drawable getDrawable(String source)
Because I need to get the drawable from the internet, I have to do it asynchronously and seems it is not.
How to make it work?
Thanks.
These guys did a great job, this is my solution using Square's Picasso library:
//...
final TextView textView = (TextView) findViewById(R.id.description);
Spanned spanned = Html.fromHtml(getIntent().getStringExtra(EXTRA_DESCRIPTION),
new Html.ImageGetter() {
#Override
public Drawable getDrawable(String source) {
LevelListDrawable d = new LevelListDrawable();
Drawable empty = getResources().getDrawable(R.drawable.abc_btn_check_material);;
d.addLevel(0, 0, empty);
d.setBounds(0, 0, empty.getIntrinsicWidth(), empty.getIntrinsicHeight());
new ImageGetterAsyncTask(DetailActivity.this, source, d).execute(textView);
return d;
}
}, null);
textView.setText(spanned);
//...
class ImageGetterAsyncTask extends AsyncTask<TextView, Void, Bitmap> {
private LevelListDrawable levelListDrawable;
private Context context;
private String source;
private TextView t;
public ImageGetterAsyncTask(Context context, String source, LevelListDrawable levelListDrawable) {
this.context = context;
this.source = source;
this.levelListDrawable = levelListDrawable;
}
#Override
protected Bitmap doInBackground(TextView... params) {
t = params[0];
try {
Log.d(LOG_CAT, "Downloading the image from: " + source);
return Picasso.with(context).load(source).get();
} catch (Exception e) {
return null;
}
}
#Override
protected void onPostExecute(final Bitmap bitmap) {
try {
Drawable d = new BitmapDrawable(context.getResources(), bitmap);
Point size = new Point();
((Activity) context).getWindowManager().getDefaultDisplay().getSize(size);
// Lets calculate the ratio according to the screen width in px
int multiplier = size.x / bitmap.getWidth();
Log.d(LOG_CAT, "multiplier: " + multiplier);
levelListDrawable.addLevel(1, 1, d);
// Set bounds width and height according to the bitmap resized size
levelListDrawable.setBounds(0, 0, bitmap.getWidth() * multiplier, bitmap.getHeight() * multiplier);
levelListDrawable.setLevel(1);
t.setText(t.getText()); // invalidate() doesn't work correctly...
} catch (Exception e) { /* Like a null bitmap, etc. */ }
}
}
My 2 cents... Peace!
Now I'm using an AsyncTask to download the images in the ImageGetter:
Spanned spannedContent = Html.fromHtml(htmlString, new ImageGetter() {
#Override
public Drawable getDrawable(String source) {
new ImageDownloadAsyncTask().execute(textView, htmlString, source);
return null;
}
}, null);
And set the text again into the TextView when the image has been downloaded.
Now it works. But It failed when I tried to do the TextView.postInvalidate() to redraw the downloaded images. I have to do setText() again in the AsyncTask.
Does anyone know why?
Here's my code that grabs all images in the html string (it's simplified from the original, so I hope it works):
private HashMap<String, Drawable> mImageCache = new HashMap<String, Drawable>();
private String mDescription = "...your html here...";
private void updateImages(final boolean downloadImages) {
if (mDescription == null) return;
Spanned spanned = Html.fromHtml(mDescription,
new Html.ImageGetter() {
#Override
public Drawable getDrawable(final String source) {
Drawable drawable = mImageCache.get(source);
if (drawable != null) {
return drawable;
} else if (downloadImages) {
new ImageDownloader(new ImageDownloader.ImageDownloadListener() {
#Override
public void onImageDownloadComplete(byte[] bitmapData) {
Drawable drawable = new BitmapDrawable(getResources(),
BitmapFactory.decodeByteArray(bitmapData, 0, bitmapData.length));
try {
drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
} catch (Exception ex) {}
mImageCache.put(source, drawable);
updateImages(false);
}
#Override
public void onImageDownloadFailed(Exception ex) {}
}).execute(source);
}
return null;
}
}, null);
tvDescription.setText(spanned);
}
So basically what happens here is the ImageGetter will make a request for every image in the html description. If that image isn't in the mImageCache array and downloadImages is true, we run an async task to download that image. Once it has completed, we add the drawable into the hashmap, and then make a call to this method again (but with downloadImages as false so we don't risk an infinite loop), where the image will be able to be grabbed with the second attempt.
And with that, you'll need the ImageDownloader class that I used:
public class ImageDownloader extends AsyncTask {
public interface ImageDownloadListener {
public void onImageDownloadComplete(byte[] bitmapData);
public void onImageDownloadFailed(Exception ex);
}
private ImageDownloadListener mListener = null;
public ImageDownloader(ImageDownloadListener listener) {
mListener = listener;
}
protected Object doInBackground(Object... urls) {
String url = (String)urls[0];
ByteArrayOutputStream baos = null;
InputStream mIn = null;
try {
mIn = new java.net.URL(url).openStream();
int bytesRead;
byte[] buffer = new byte[64];
baos = new ByteArrayOutputStream();
while ((bytesRead = mIn.read(buffer)) > 0) {
if (isCancelled()) return null;
baos.write(buffer, 0, bytesRead);
}
return new AsyncTaskResult<byte[]>(baos.toByteArray());
} catch (Exception ex) {
return new AsyncTaskResult<byte[]>(ex);
}
finally {
Quick.close(mIn);
Quick.close(baos);
}
}
protected void onPostExecute(Object objResult) {
AsyncTaskResult<byte[]> result = (AsyncTaskResult<byte[]>)objResult;
if (isCancelled() || result == null) return;
if (result.getError() != null) {
mListener.onImageDownloadFailed(result.getError());
}
else if (mListener != null)
mListener.onImageDownloadComplete(result.getResult());
}
}
Related
My app consist of a textview and a string, that string contain a img tag html code, i'm assign that string to the textview using ImageGetter to display the image, and image is retrieving and displaying in the app. But that string also contain style tag, which contains both height and width attributes, now i need to get those attributes values and assign to the mDrawable in onPostExecute().
Here is my MainActivity look like:
public class MainActivity extends Activity implements ImageGetter {
private final static String TAG = "MainActivity";
private TextView mTv;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String imgs = "<p><img alt=\"\" src=\"https://rukminim1.flixcart.com/image/832/832/screwdriver-set/6/3/f/41pcs-aecone-original-imaedhrtthffafup.jpeg?q=70\" style=\"height:100px; width:100px\" />";
Spanned spanned = Html.fromHtml(imgs, this, null);
mTv = (TextView) findViewById(R.id.text);
mTv.setText(spanned);
}
#Override
public Drawable getDrawable(String source) {
LevelListDrawable d = new LevelListDrawable();
Drawable empty = getResources().getDrawable(R.mipmap.ic_launcher);
d.addLevel(0, 0, empty);
d.setBounds(0, 0, empty.getIntrinsicWidth(), empty.getIntrinsicHeight());
new LoadImage().execute(source, d);
return d;
}
class LoadImage extends AsyncTask<Object, Void, Bitmap> {
private LevelListDrawable mDrawable;
#Override
protected Bitmap doInBackground(Object... params) {
String source = (String) params[0];
mDrawable = (LevelListDrawable) params[1];
Log.d(TAG, "doInBackground " + params[0]);
try {
InputStream is = new URL(source).openStream();
return BitmapFactory.decodeStream(is);
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Bitmap bitmap) {
Log.d(TAG, "onPostExecute drawable " + mDrawable);
Log.d(TAG, "onPostExecute bitmap " + bitmap);
if (bitmap != null) {
BitmapDrawable d = new BitmapDrawable(bitmap);
mDrawable.addLevel(1, 1, d);
mDrawable.setBounds(0, 0, bitmap.getWidth(), bitmap.getHeight());
mDrawable.setLevel(1);
// i don't know yet a better way to refresh TextView
// mTv.invalidate() doesn't work as expected
CharSequence t = mTv.getText();
mTv.setText(t);
}
}
}
}
When using Custom Class show a pic on TextView,
I use spanned to show A NetImage on TextView, \
code like Below
Spanned spanned = Html.fromHtml(string, new NetImageGetter(mContext, holderNormal.tv_content),
new NetTagHandler(mContext));
holderNormal.tv_content.setText(spanned);
NetImageGetter like below:
public class NetImageGetter implements ImageGetter {
private Context context;
private TextView tv;
private int height;
public NetImageGetter(Context context, TextView tv) {
this.context = context;
this.tv = tv;
height = CommonUtil.dip2px(context, 18);
if (height == 0) {
height = 36;
}
}
#Override
public Drawable getDrawable(String source) {
// 将source进行MD5加密并保存至本地
String imageName = Common.md5(source);
String rootPath = QikeApplication.mCacheNeedClearDir; // 获取SDCARD的路径
// 获取图片后缀名
String[] ss = source.split("\\.");
String ext = ss[ss.length - 1];
// 最终图片保持的地址
String savePath = rootPath + "/" + imageName + "." + ext;
File file = new File(savePath);
if (file.exists()) {
// 如果文件已经存在，直接返回
Drawable drawable = Drawable.createFromPath(savePath);
if (drawable != null) {
int picHeight = drawable.getIntrinsicHeight();
int picWidth = drawable.getIntrinsicWidth();
drawable.setBounds(0, 0, ((int) (height / picHeight * picWidth)), height);
return drawable;
}
}
// 不存在文件时返回默认图片，并异步加载网络图片
Resources res = context.getResources();
URLDrawable drawable = new URLDrawable(res.getDrawable(R.drawable.icon));
new ImageAsync(drawable).execute(savePath, source);
return drawable;
}
private class ImageAsync extends AsyncTask<String, Integer, Drawable> {
private URLDrawable drawable;
public ImageAsync(URLDrawable drawable) {
this.drawable = drawable;
}
#Override
protected Drawable doInBackground(String... params) {
String savePath = params[0];
String url = params[1];
InputStream in = null;
try {
// 获取网络图片
HttpGet http = new HttpGet(url);
HttpClient client = new DefaultHttpClient();
HttpResponse response = (HttpResponse) client.execute(http);
BufferedHttpEntity bufferedHttpEntity = new BufferedHttpEntity(response.getEntity());
in = bufferedHttpEntity.getContent();
} catch (Exception e) {
e.printStackTrace();
try {
if (in != null)
in.close();
} catch (Exception e2) {
}
}
if (in == null)
return drawable;
try {
File file = new File(savePath);
String basePath = file.getParent();
File basePathFile = new File(basePath);
if (!basePathFile.exists()) {
basePathFile.mkdirs();
}
file.createNewFile();
FileOutputStream fileout = new FileOutputStream(file);
byte[] buffer = new byte[1024];
int len = 0;
while ((len = in.read(buffer)) != -1) {
fileout.write(buffer, 0, len);
}
fileout.flush();
Drawable mDrawable = Drawable.createFromPath(savePath);
return mDrawable;
} catch (Exception e) {
e.printStackTrace();
}
return drawable;
}
#Override
protected void onPostExecute(Drawable result) {
super.onPostExecute(result);
if (result != null) {
drawable.setDrawable(result);
tv.setText(tv.getText()); // 通过这里的重新设置 TextView 的文字来更新UI
}
}
}
public class URLDrawable extends BitmapDrawable {
private Drawable drawable;
public URLDrawable(Drawable defaultDraw) {
setDrawable(defaultDraw);
}
private void setDrawable(Drawable nDrawable) {
drawable = nDrawable;
int picHeight = drawable.getIntrinsicHeight();
int picWidth = drawable.getIntrinsicWidth();
if (picWidth != 0) {
drawable.setBounds(0, 0, ((int) (height / picHeight * picWidth)), height);
setBounds(0, 0, ((int) (height / picHeight * picWidth)), height);
}
}
#Override
public void draw(Canvas canvas) {
try {
drawable.draw(canvas);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
And use it on a adapter
run normal,but on some phone type, throw a StackOverflowError on
java.lang.StackOverflowError
at com.telecast.library.util.NetPicTextView.NetImageGetter$URLDrawable.draw(NetImageGetter.java:166)
I write a try catch,but useless.
Someone can help me?
I have used the async task to download the data and then showing those images in the list view I used the cache to store the images as they are repeating but not in an order. But the images gets jumbled up and sometimes they don't download. I tried searching this, but couldn't find that.
This was one of mine dream company question and i didn't clear because of this.
Please help me around.
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
private static final String BASE_URL = "https://ajax.googleapis.com/ajax/services/search/images?v=1.0&q=android&start=";
private static final String IMAGE_JSON_KEY = "unescapedUrl";
private static final String RESULTS_JSON_KEY = "results";
private static final String RESPONSE_DATA_JSON_KEY = "responseData";
private int mCurrentPage;
private ListView mListView;
private Context mContext;
ArrayList<String> mImageUrls;
private LruCache<String, Bitmap> mCache;
private CustomListAdapter mAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Get memory class of this device, exceeding this amount will throw an
// OutOfMemory exception.
final int memClass = ((ActivityManager) getSystemService(Context.ACTIVITY_SERVICE)).getMemoryClass();
// Use 1/8th of the available memory for this memory cache.
final int cacheSize = 1024 * 1024 * memClass / 8;
// Initialize variables
mContext = this;
mCache = new LruCache<String, Bitmap>(cacheSize) {
#Override
protected int sizeOf(String key, Bitmap value) {
// The cache size will be measured in bytes rather than number of items.
return value.getByteCount();
}
};
mListView = (ListView) findViewById(R.id.list_view);
mAdapter = new CustomListAdapter();
mImageUrls = new ArrayList<>();
// If the urls are wrong then
if (mImageUrls.isEmpty() || checkDiff()) {
fetchNewImageUrls();
}
// Set the adapter to the list view
mListView.setAdapter(mAdapter);
}
class BitmapWorkerTask extends AsyncTask<String, Void, Bitmap> {
private final WeakReference<ImageView> imageViewReference;
private String mUrl;
public BitmapWorkerTask(ImageView imageView) {
// Use a WeakReference to ensure the ImageView can be garbage collected
imageViewReference = new WeakReference<ImageView>(imageView);
}
#Override
protected Bitmap doInBackground(String... params) {
String imageUrl = params[0];
mUrl = imageUrl;
Bitmap bitmap = getBitmapFromMemCache(imageUrl);
if (bitmap == null) {
try {
URL url = new URL(imageUrl);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);
connection.connect();
// Closing the stream after getting the sample size
InputStream inputStream = connection.getInputStream();
byte[] imageByteArray = convertToByteArray(inputStream);
bitmap = decodeSampledBitmap(imageByteArray, 200, 200);
inputStream.close();
if (bitmap != null) {
Log.d(TAG, "Image downloaded: " + imageUrl);
addBitmapToMemoryCache(imageUrl, bitmap);
} else {
Log.d(TAG, "Null Bitmap downloaded for: " + imageUrl);
}
connection.disconnect();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
} else {
Log.d(TAG, "Already present in the Cache");
}
return bitmap;
}
#Override
protected void onPostExecute(Bitmap bitmap) {
if (imageViewReference != null && bitmap != null) {
final ImageView imageView = (ImageView) imageViewReference.get();
if (imageView != null && imageView.getTag().equals(mUrl)) {
imageView.setImageBitmap(bitmap);
}
}
}
}
public class CustomListAdapter extends BaseAdapter {
#Override
public int getCount() {
return mImageUrls.size();
}
#Override
public Object getItem(int position) {
return mImageUrls.get(position);
}
#Override
public long getItemId(int position) {
return position;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
Log.d(TAG, "Get View is called for position: " + position);
View view = convertView;
Holder holder = null;
// Holder represents the elements of the view to use
// Here are initialized
if (view == null) {
view = LayoutInflater.from(mContext).inflate(R.layout.row_item, parent, false);
holder = new Holder();
holder.mRowImage = (ImageView) view.findViewById(R.id.image_view);
holder.mRowText = (TextView) view.findViewById(R.id.row_text);
view.setTag(holder);
} else {
holder = (Holder) view.getTag();
}
// Set default image background
holder.mRowImage.setImageResource(R.drawable.ic_launcher);
// here do operations in holder variable example
holder.mRowText.setText("Image Number: " + position);
// Set the tag for the imageview
holder.mRowImage.setTag(mImageUrls.get(position));
new BitmapWorkerTask(holder.mRowImage).execute(mImageUrls.get(position));
return view;
}
}
public static class Holder {
TextView mRowText;
ImageView mRowImage;
}
public void addBitmapToMemoryCache(String key, Bitmap bitmap) {
if (getBitmapFromMemCache(key) == null) {
mCache.put(key, bitmap);
}
}
public Bitmap getBitmapFromMemCache(String key) {
return (Bitmap) mCache.get(key);
}
public Bitmap decodeSampledBitmap(byte[] imageByteArray, int reqWidth, int reqHeight) {
Bitmap bm = null;
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeByteArray(imageByteArray, 0, imageByteArray.length, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
options.inJustDecodeBounds = false;
bm = BitmapFactory.decodeByteArray(imageByteArray, 0, imageByteArray.length, options);
return bm;
}
public int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
if (width > height) {
inSampleSize = Math.round((float) height / (float) reqHeight);
} else {
inSampleSize = Math.round((float) width / (float) reqWidth);
}
}
Log.d(TAG, "Sample size is: " + inSampleSize);
return inSampleSize;
}
private void fetchNewImageUrls() {
new AsyncTask<String, Void, Boolean>() {
#Override
protected Boolean doInBackground(String... params) {
try {
StringBuilder response = new StringBuilder();
URL url = new URL(params[0]);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.connect();
BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String inputLine;
while ((inputLine = in.readLine()) != null)
response.append(inputLine);
in.close();
connection.disconnect();
String resp = response.toString();
Log.d(TAG, "Response is: " + response);
// Parsing the response
JSONObject jsonObject = new JSONObject(resp);
JSONObject jsonObject1 = jsonObject.getJSONObject(RESPONSE_DATA_JSON_KEY);
JSONArray jsonArray = jsonObject1.getJSONArray(RESULTS_JSON_KEY);
for (int i = 0; i < 4; i++) {
JSONObject dataObject = jsonArray.getJSONObject(i);
mImageUrls.add(dataObject.getString(IMAGE_JSON_KEY));
}
mCurrentPage++;
Log.d(TAG, "Number of image urls are: " + mImageUrls.size());
return true;
} catch (JSONException e) {
e.printStackTrace();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return false;
}
#Override
protected void onPostExecute(Boolean value) {
super.onPostExecute(value);
if (checkDiff() && value) {
Log.d(TAG, "Again fetching the Images");
fetchNewImageUrls();
}
if (!value) {
Log.d(TAG, "Error while getting the response");
}
mAdapter.notifyDataSetChanged();
}
}.execute(BASE_URL + mCurrentPage);
}
private boolean checkDiff() {
int diff = mImageUrls.size() - mCurrentPage * 4;
Log.d(TAG, "Diff is: " + diff);
return diff < 8;
}
public static byte[] convertToByteArray(InputStream input) {
byte[] buffer = new byte[8192];
int bytesRead;
ByteArrayOutputStream output = new ByteArrayOutputStream();
try {
while ((bytesRead = input.read(buffer)) != -1) {
output.write(buffer, 0, bytesRead);
}
} catch (IOException e) {
e.printStackTrace();
}
return output.toByteArray();
}
}
Since you do not cancel the unfinished "out of view" downloads these may interfere with your gui.
Example
listview line1 shows item#1 with has an async task to download image "a" not completed yet
scroll down, line1 is now invisible;
listview line8 becomes visible recycling item#1 new async task to download image "x"
async task to download image "a" finishes displaying wrong image. Line8 shows image "a" instead of "x"
to solve this you have to cancel the pending unnecessary unfinished async task-s
public static class Holder {
ImageView mRowImage;
String mImageUrl;
// neccessary to cancel unfinished download
BitmapWorkerTask mDownloader;
}
static class BitmapWorkerTask extends AsyncTask<Holder, Void, Bitmap> {
Holder mHolder;
protected Bitmap doInBackground(Holder... holders) {
mHolder = holders[0];
...
}
protected void onPostExecute(...) {
mHolder.mDownloader = null;
if (!isCancelled()) {
this.mHolder.mRowImage.setImageBitmap(image);
}
this.mHolder = null;
}
}
public class CustomListAdapter extends BaseAdapter {
#Override
public View getView(int position, ...) {
...
if (view == null) {
holder = ...
...
} else {
holder = (Holder) view.getTag();
}
...
// cancel unfinished mDownloader
if (holder.mDownloader != null) {
holder.mDownloader.cancel(false);
holder.mDownloader = null;
}
holder.mImageUrl = mImageUrls.get(position);
holder.mDownloader = new BitmapWorkerTask()
holder.mDownloader.execute(holder);
}
}
Here is a working example for this combination of Adapter + Holder + AsyncTask
[Update]
Potential problems with this solution.
Most modern android versions execute only one async task at a time. If you are fetching the images via the web you cannot download multible images at the same time. See running-parallel-asynctask#stackoverflow for details.
There may be promlems with configuration change(like orientation). See #Selvin-s comment below. I have posted this question "what-happens-with-view-references-in-unfinished-asynctask-after-orientation-chan#stackoverflow" to find out more about it.
I am struggling to update a list view with data from a database, this works nicely by using a SimpleCursorAdapter. But the image view on the rows is not updated on the activity start, I have to scroll through the list a few times and only then the images are loaded in the image view.
This is the binder i am using for the SimpleCursorAdapter:
private class PromotionViewBinder implements SimpleCursorAdapter.ViewBinder {
private int done;
public boolean setViewValue(View view, Cursor cursor, int index) {
Log.e(""+cursor.getCount(),"");
View tmpview = view;
if (index == cursor.getColumnIndex(PromotionsTable.SEEN_COL)) {
boolean read = cursor.getInt(index) > 0 ? true : false;
TextView title = (TextView) tmpview;
if (!read) {
title.setTypeface(Typeface.DEFAULT_BOLD, 0);
} else {
title.setTypeface(Typeface.DEFAULT);
}
return true;
} else if (tmpview.getId() == R.id.promotions_list_row_image){
String imageURL = cursor.getString(index);
Log.e("",imageURL);
imageRetriever.displayImage(imageURL, (ImageView)tmpview);
return true;
} else {
return false;
}
}
}
The image retriever class is the LazyList example from here. As you will see this is using a runnable to retrieve the images and once the task is done is automatically updating the given imageView...Do you think that the reference to the imageView is lost somewhere on the way?
Thanx in advance,
Nick
package com.tipgain.promotions;
The image retriever class:
/**
* This class is used for retrieving images from a given web link. it uses local
* storage and memory to store the images. Once a image is downloaded
* successfully the UI gets updated automatically.
*
*
*/
public class ImageRetriever {
private final String TAG = ImageRetriever.class.getName();
private MemoryImageCache memoryImgCache = new MemoryImageCache();
private LocalStorageImageCache localFileCache;
private Map<ImageView, String> imageViewHolders = Collections
.synchronizedMap(new WeakHashMap<ImageView, String>());
private ExecutorService execService;
final int defaultImageID = R.drawable.photo_not_available;
public ImageRetriever(Context context) {
localFileCache = new LocalStorageImageCache(context);
execService = Executors.newFixedThreadPool(5);
}
public void displayImage(String url, ImageView imageView) {
imageViewHolders.put(imageView, url);
Bitmap bmp = memoryImgCache.retrieve(url);
if (bmp != null) {
Log.e("case 1", " " + (bmp != null));
imageView.setImageBitmap(bmp);
} else {
Log.e("case 2", " " + (bmp == null));
addImageToQueue(url, imageView);
imageView.setImageResource(defaultImageID);
}
}
private void addImageToQueue(String url, ImageView imageView) {
NextImageToLoad img = new NextImageToLoad(url, imageView);
execService.submit(new ImagesRetriever(img));
}
/**
* This method is used for retrieving the Bitmap Image.
*
* #param url
* String representing the url pointing to the image.
* #return Bitmap representing the image
*/
private Bitmap getBitmap(String url) {
File imageFile = localFileCache.getFile(url);
// trying to get the bitmap from the local storage first
Bitmap bmp = decodeImageFile(imageFile);
if (bmp != null)
return bmp;
// if the file was not found locally we retrieve it from the web
try {
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(imageFile);
Utils.CopyStream(is, os);
os.close();
bmp = decodeImageFile(imageFile);
return bmp;
} catch (MalformedURLException e) {
Log.e(TAG, e.getMessage());
} catch (FileNotFoundException e) {
Log.e(TAG, e.getMessage());
} catch (IOException e) {
Log.e(TAG, e.getMessage());
}
return null;
}
/**
* This method is used for decoding a given image file. Also, to reduce
* memory, the image is also scaled.
*
* #param imageFile
* #return
*/
private Bitmap decodeImageFile(File imageFile) {
try {
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(imageFile), null,
options);
// Find the correct scale value. It should be the power of 2.
// Deciding the perfect scaling value. (^2).
final int REQUIRED_SIZE = 100;
int tmpWidth = options.outWidth, tmpHeight = options.outHeight;
int scale = 1;
while (true) {
if (tmpWidth / 2 < REQUIRED_SIZE
|| tmpHeight / 2 < REQUIRED_SIZE)
break;
tmpWidth /= 2;
tmpHeight /= 2;
scale *= 2;
}
// decoding using inSampleSize
BitmapFactory.Options option2 = new BitmapFactory.Options();
option2.inSampleSize = scale;
return BitmapFactory.decodeStream(new FileInputStream(imageFile),
null, option2);
} catch (FileNotFoundException e) {
Log.e(TAG, e.getLocalizedMessage());
}
return null;
}
private boolean reusedImage(NextImageToLoad image) {
Context c = image.imageView.getContext();
c.getContentResolver().notifyChange(PromotionsProvider.CONTENT_URI, null);
String tag = imageViewHolders.get(image.imageView);
if ((tag == null) || (!tag.equals(image.url)))
return true;
return false;
}
/**
* Clears the Memory and Local cache
*/
public void clearCache() {
memoryImgCache.clear();
localFileCache.clear();
}
/**
* This class implements a runnable that is used for updating the promotions
* images on the UI
*
*
*/
class UIupdater implements Runnable {
Bitmap bmp;
NextImageToLoad image;
public UIupdater(Bitmap bmp, NextImageToLoad image) {
this.bmp = bmp;
this.image = image;
Log.e("", "ui updater");
}
public void run() {
Log.e("ui updater", "ui updater");
if (reusedImage(image))
return;
Log.e("nick", "" + (bmp == null) + " chberugv");
if (bmp != null){
image.imageView.setImageBitmap(bmp);
Context c = image.imageView.getContext();
c.getContentResolver().notifyChange(PromotionsProvider.CONTENT_URI, null);
}else
image.imageView.setImageResource(defaultImageID);
}
}
private class ImagesRetriever implements Runnable {
NextImageToLoad image;
ImagesRetriever(NextImageToLoad image) {
this.image = image;
}
public void run() {
Log.e("images retirever", " images retriever");
if (reusedImage(image))
return;
Bitmap bmp = getBitmap(image.url);
memoryImgCache.insert(image.url, bmp);
if (reusedImage(image))
return;
UIupdater uiUpdater = new UIupdater(bmp, image);
Activity activity = (Activity) image.imageView.getContext();
activity.runOnUiThread(uiUpdater);
//Context c = image.imageView.getContext();
//c.getContentResolver().notifyChange(PromotionsProvider.CONTENT_URI, null);
}
}
/**
* This class encapsulates the image being downloaded.
*
* #author Nicolae Anca
*
*/
private class NextImageToLoad {
public String url;
public ImageView imageView;
public NextImageToLoad(String u, ImageView i) {
url = u;
imageView = i;
}
}
}
Modified Runnable:
class UIupdater implements Runnable {
Bitmap bmp;
NextImageToLoad image;
public UIupdater(Bitmap bmp, NextImageToLoad image) {
this.bmp = bmp;
this.image = image;
}
public void run() {
if (reusedImage(image))
return;
if (bmp != null){
image.imageView.setImageBitmap(bmp);
Context c = image.imageView.getContext();
c.getContentResolver().notifyChange(PromotionsProvider.CONTENT_URI, null);
}else
image.imageView.setImageResource(defaultImageID);
}
}
Thats an interesting way to do what you are doing. Have you tried extending the Simple Cursor Adapter?
What you do is implement a ViewHolder and put your imageview in it.
Then in your ImageRetriever, write a Listener which will be called once the image is ready and retrieved.
Implement this listener in the Viewholder.
You create the view in getView() and request for the image in BindView().
Once the image gets loaded, the list will be refreshed automatically.
one way to do it is by calling notifyDataSetChenged on listview, and another was is to have adapter as member variable and when something changes on listview you call a function that assigns new listadapter to member adapter. That way your list will be redraw on change.
I guess, you have to use some handler, calling after image load, which will call notifyDataSetChanged for list adapter
I have a custom view with a lot of png images on it(For every three characters an image). but it is too slow on drawing and scrolling.
It is my code for custom view:
public class Textview extends View
{
private String m_szText;
Context ctx;
Paint mTextPaint;
private Canvas canva;
Bitmap b ;
public Textview(Context context)
{
super(context);
ctx = context;
mTextPaint= new Paint();
mTextPaint.setTypeface(m_tTypeface);
mTextPaint.setStyle(Paint.Style.FILL);
}
public void SetText(String newtext) {
m_szText = newtext;
text(newtext);
this.invalidate();
}
#Override
protected void onDraw(Canvas canvas)
{
super.onDraw(text(canvas,m_szText));
}
Canvas text(Canvas canvas,String txt)
{
int left = 400;
int top = 0;
try {
for(int i=0;i<txt.length();i=i+3)
{
String adres = "glyph/" + txt.substring(i, i+3) + ".png";
Bitmap btm = getBitmapFromAsset(adres);
if(left <= 5)
{left = 400;top += btm.getHeight();}
else
left = left - btm.getWidth();
canvas.drawBitmap(btm, left ,top,mTextPaint);
}
} catch (IOException e) {
canvas.drawText(e.toString(), 50, 50, mTextPaint);
}
return canvas;
}
private Bitmap getBitmapFromAsset(String strName) throws IOException
{
AssetManager assetManager = ctx.getAssets();
InputStream istr = assetManager.open(strName);
Bitmap bitmap = BitmapFactory.decodeStream(istr);
return bitmap;
}
}
How can I speed up my custom view? I think I must to create bitmap of all images once. but how to?
thanks in advance!
You are loading and decoding several bitmaps on every draw. You need to load the bitmaps ahead of time, once and then draw them.
You can use Thread to speed up process, and there are two way to use thread
1)Implementing Runnable that override void run(){}
2)or use Thread th=new Thread(new Runnable(){void run(){}
})
The following should help. just outline of what can be done.
static HashMap<String, Bitmap> mBitmaps = new HashMap<String, Bitmap>();
public void SetText(String newtext) {
m_szText = newtext;
makeBitmap();
this.invalidate();
}
void makeBitmap()
{
for(int i=0; i<m_szText.length(); i=i+3)
{
String adres = "glyph/" + m_szText.substring(i, i+3) + ".png";
Bitmap btm = null;
if (!mBitmaps.containsKey(adres)) {
btm = getBitmapFromAsset(adres);
mBitmaps.add(adres , btm);
} else {
btm = (Bitmap)mBitmaps.get(adres);
}
length += btm.getWidth(); // considering only single line.
}
// create a new blank Bitmap of height and 'length' and assign to member.
mTextBitmap = Bitmap.createBitmap(length, height, Bitmap.Config.ARGB_8888);
// in for loop draw all the bitmaps on mTextBitmap just like you did on canvas in ur code.
}