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Powerful and flexible instrument for asynchronous image loading, caching and displaying on Android
/*******************************************************************************
* Copyright 2011-2013 Sergey Tarasevich
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*******************************************************************************/
package com.nostra13.universalimageloader.core.download;
import android.content.ContentResolver;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.drawable.BitmapDrawable;
import android.net.Uri;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
/**
* Provides retrieving of {@link InputStream} of image by URI from network or file system or app resources.
* {@link URLConnection} is used to retrieve image stream from network.
*
* @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
* @see HttpClientImageDownloader
* @since 1.8.0
*/
public class BaseImageDownloader implements ImageDownloader {
/** {@value} */
public static final int DEFAULT_HTTP_CONNECT_TIMEOUT = 5 * 1000; // milliseconds
/** {@value} */
public static final int DEFAULT_HTTP_READ_TIMEOUT = 20 * 1000; // milliseconds
/** {@value} */
protected static final int BUFFER_SIZE = 32 * 1024; // 32 Kb
/** {@value} */
protected static final String ALLOWED_URI_CHARS = "@#&=*+-_.,:!?()/~'%";
protected static final int MAX_REDIRECT_COUNT = 5;
private static final String ERROR_UNSUPPORTED_SCHEME = "UIL doesn't support scheme(protocol) by default [%s]. "
+ "You should implement this support yourself (BaseImageDownloader.getStreamFromOtherSource(...))";
protected final Context context;
protected final int connectTimeout;
protected final int readTimeout;
public BaseImageDownloader(Context context) {
this.context = context.getApplicationContext();
this.connectTimeout = DEFAULT_HTTP_CONNECT_TIMEOUT;
this.readTimeout = DEFAULT_HTTP_READ_TIMEOUT;
}
public BaseImageDownloader(Context context, int connectTimeout, int readTimeout) {
this.context = context.getApplicationContext();
this.connectTimeout = connectTimeout;
this.readTimeout = readTimeout;
}
@Override
public InputStream getStream(String imageUri, Object extra) throws IOException {
switch (Scheme.ofUri(imageUri)) {
case HTTP:
case HTTPS:
return getStreamFromNetwork(imageUri, extra);
case FILE:
return getStreamFromFile(imageUri, extra);
case CONTENT:
return getStreamFromContent(imageUri, extra);
case ASSETS:
return getStreamFromAssets(imageUri, extra);
case DRAWABLE:
return getStreamFromDrawable(imageUri, extra);
case UNKNOWN:
default:
return getStreamFromOtherSource(imageUri, extra);
}
}
/**
* Retrieves {@link InputStream} of image by URI (image is located in the network).
*
* @param imageUri Image URI
* @param extra Auxiliary object which was passed to {@link DisplayImageOptions.Builder#extraForDownloader(Object)
* DisplayImageOptions.extraForDownloader(Object)}; can be null
* @return {@link InputStream} of image
* @throws IOException if some I/O error occurs during network request or if no InputStream could be created for
* URL.
*/
protected InputStream getStreamFromNetwork(String imageUri, Object extra) throws IOException {
HttpURLConnection conn = createConnection(imageUri, extra);
int redirectCount = 0;
while (conn.getResponseCode() / 100 == 3 && redirectCount < MAX_REDIRECT_COUNT) {
conn = createConnection(conn.getHeaderField("Location"), extra);
redirectCount++;
}
return new BufferedInputStream(conn.getInputStream(), BUFFER_SIZE);
}
/**
* Create {@linkplain HttpURLConnection HTTP connection} for incoming URL
*
* @param url URL to connect to
* @param extra Auxiliary object which was passed to {@link DisplayImageOptions.Builder#extraForDownloader(Object)
* DisplayImageOptions.extraForDownloader(Object)}; can be null
* @return {@linkplain HttpURLConnection Connection} for incoming URL. Connection isn't established so it still configurable.
* @throws IOException if some I/O error occurs during network request or if no InputStream could be created for
* URL.
*/
protected HttpURLConnection createConnection(String url, Object extra) throws IOException {
String encodedUrl = Uri.encode(url, ALLOWED_URI_CHARS);
HttpURLConnection conn = (HttpURLConnection) new URL(encodedUrl).openConnection();
conn.setConnectTimeout(connectTimeout);
conn.setReadTimeout(readTimeout);
return conn;
}
/**
* Retrieves {@link InputStream} of image by URI (image is located on the local file system or SD card).
*
* @param imageUri Image URI
* @param extra Auxiliary object which was passed to {@link DisplayImageOptions.Builder#extraForDownloader(Object)
* DisplayImageOptions.extraForDownloader(Object)}; can be null
* @return {@link InputStream} of image
* @throws IOException if some I/O error occurs reading from file system
*/
protected InputStream getStreamFromFile(String imageUri, Object extra) throws IOException {
String filePath = Scheme.FILE.crop(imageUri);
return new BufferedInputStream(new FileInputStream(filePath), BUFFER_SIZE);
}
/**
* Retrieves {@link InputStream} of image by URI (image is accessed using {@link ContentResolver}).
*
* @param imageUri Image URI
* @param extra Auxiliary object which was passed to {@link DisplayImageOptions.Builder#extraForDownloader(Object)
* DisplayImageOptions.extraForDownloader(Object)}; can be null
* @return {@link InputStream} of image
* @throws FileNotFoundException if the provided URI could not be opened
*/
protected InputStream getStreamFromContent(String imageUri, Object extra) throws FileNotFoundException {
ContentResolver res = context.getContentResolver();
Uri uri = Uri.parse(imageUri);
return res.openInputStream(uri);
}
/**
* Retrieves {@link InputStream} of image by URI (image is located in assets of application).
*
* @param imageUri Image URI
* @param extra Auxiliary object which was passed to {@link DisplayImageOptions.Builder#extraForDownloader(Object)
* DisplayImageOptions.extraForDownloader(Object)}; can be null
* @return {@link InputStream} of image
* @throws IOException if some I/O error occurs file reading
*/
protected InputStream getStreamFromAssets(String imageUri, Object extra) throws IOException {
String filePath = Scheme.ASSETS.crop(imageUri);
return context.getAssets().open(filePath);
}
/**
* Retrieves {@link InputStream} of image by URI (image is located in drawable resources of application).
*
* @param imageUri Image URI
* @param extra Auxiliary object which was passed to {@link DisplayImageOptions.Builder#extraForDownloader(Object)
* DisplayImageOptions.extraForDownloader(Object)}; can be null
* @return {@link InputStream} of image
*/
protected InputStream getStreamFromDrawable(String imageUri, Object extra) {
String drawableIdString = Scheme.DRAWABLE.crop(imageUri);
int drawableId = Integer.parseInt(drawableIdString);
BitmapDrawable drawable = (BitmapDrawable) context.getResources().getDrawable(drawableId);
Bitmap bitmap = drawable.getBitmap();
ByteArrayOutputStream os = new ByteArrayOutputStream();
bitmap.compress(CompressFormat.PNG, 0, os);
return new ByteArrayInputStream(os.toByteArray());
}
/**
* Retrieves {@link InputStream} of image by URI from other source with unsupported scheme. Should be overriden by
* successors to implement image downloading from special sources.
* This method is called only if image URI has unsupported scheme. Throws {@link UnsupportedOperationException} by
* default.
*
* @param imageUri Image URI
* @param extra Auxiliary object which was passed to {@link DisplayImageOptions.Builder#extraForDownloader(Object)
* DisplayImageOptions.extraForDownloader(Object)}; can be null
* @return {@link InputStream} of image
* @throws IOException if some I/O error occurs
* @throws UnsupportedOperationException if image URI has unsupported scheme(protocol)
*/
protected InputStream getStreamFromOtherSource(String imageUri, Object extra) throws IOException {
throw new UnsupportedOperationException(String.format(ERROR_UNSUPPORTED_SCHEME, imageUri));
}
}