I am retrieving images from a url. Instead of caching the images, would it by any chance be possible to store it in a SQLite database?
/** Simple Constructor saving the 'parent' context. */
public ImageAdapter(Context c) { this.myContext = c; }
/** Returns the amount of images we have defined. */
public int getCount() { return this.myRemoteImages.length; }
/* Use the array-Positions as unique IDs */
public Object getItem(int position) { return position; }
public long getItemId(int position) { return position; }
/** Returns a new ImageView to
* be displayed, depending on
* the position passed. */
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(this.myContext);
try {
URL aURL = new URL(myRemoteImages[position]);
URLConnection conn = aURL.openConnection();
conn.connect();
InputStream is = conn.getInputStream();
/* Buffered is always good for a performance plus. */
BufferedInputStream bis = new BufferedInputStream(is);
/* Decode url-data to a bitmap. */
Bitmap bm = BitmapFactory.decodeStream(bis);
bis.close();
is.close();
Log.v(imageUrl, "Retrieving image");
/* Apply the Bitmap to the ImageView that will be returned. */
i.setImageBitmap(bm);
} catch (IOException e) {
开发者_运维问答 Log.e("DEBUGTAG", "Remtoe Image Exception", e);
}
/* Image should be scaled as width/height are set. */
i.setScaleType(ImageView.ScaleType.FIT_CENTER);
/* Set the Width/Height of the ImageView. */
if(Build.VERSION.SDK_INT >= 11){
i.setLayoutParams(new Gallery.LayoutParams(450, 300));
return i;
}
else{
i.setLayoutParams(new Gallery.LayoutParams(125, 125));
return i;
}
}
/** Returns the size (0.0f to 1.0f) of the views
* depending on the 'offset' to the center. */
public float getScale(boolean focused, int offset) {
/* Formula: 1 / (2 ^ offset) */
return Math.max(0, 1.0f / (float)Math.pow(2, Math.abs(offset)));
}
}
EDIT: Set the imageAdapter to load images in Gallery
((Gallery) findViewById(R.id.gallery))
.setAdapter(new ImageAdapter(MainMenu.this));
protected Drawable Imagehandler(String url) {
try {
url=url.replaceAll(" ", "%20");
InputStream is = (InputStream)this.fetch(url);
Drawable d = Drawable.createFromStream(is, "src");
return d;
} catch (MalformedURLException e)
{
System.out.println(url);
System.out.println("error at URI"+e);
return null;
}
catch (IOException e)
{
System.out.println("io exception: "+e);
System.out.println("Image NOT FOUND");
return null;
}
}
protected Object fetch(String address) throws MalformedURLException,IOException {
URL url = new URL(address);
Object content = url.getContent();
return content;
}
this will convert your imageUrl to Drawble at runtime, then set the Drawble to Imageview of Gallery
ya you can store image as BLOB in your database,
public static byte[] urlToImageBLOB(String url) throws IOException {
httpclient = new DefaultHttpClient();
entity = null;
httpGet = new HttpGet(url);
response = httpclient.execute(httpGet);
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
entity = response.getEntity();
}
return EntityUtils.toByteArray(entity);
}
To fetch
public static Bitmap getImageFromBLOB(byte[] mBlob) {
byte[] bb = mBlob;
return BitmapFactory.decodeByteArray(bb, 0, bb.length);
}
// to set imageView.setImageBitmap(getImageFromBLOB(cursor.getBlob(object.getColumnIndex("book_thumb"))));
Here's a link to how you store data in external storage: External storage
The link explains where to place files (if you want to use external storage), and how to check if external storage is available.
Edit: How you access files, is explained under the topic "Accessing files on external storage".
You should in API 8, or above invoke getExternalFilesDir()
to get a File
that represents your applications root directory. You can then read and write the files as you normally do (using e.g. FileWriter and FileReader for text data)
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