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Android开发之一种简单的异步加载图片方法
首先说明的是，该方法已经被我抛弃了。之前用它，发现加载速度不好。具体没怎么细心的看。
现在我用volley了。拿出来只是给大家批判的。
package com.souya.seller.util.ex;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.lang.ref.SoftReference;
import java.util.HashMap;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import AXLib.Utility.Console;
import AXLib.Utility.HttpClient;
import AXLib.Utility.Queue;
import AXLib.Utility.RuntimeExceptionEx;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.media.ThumbnailUtils;
import android.net.Uri;
import android.os.Handler;
import android.os.Message;
import android.provider.MediaStore.Video.Thumbnails;
import android.util.Log;
import android.widget.ImageView;
import com.souya.seller.app.SellerApplication;
public class AsyncImageLoader {
private static boolean _D = false;//AppConfig._D &&
private static final String TAG = "AsyncImageLoader";
public static String CachePath = null;
private static String ThumbnailPath = null;
private static boolean _isInit = false;
private static Context _ctx;
private static Bitmap _empty = Bitmap.createBitmap(1, 1, Bitmap.Config.RGB_565);
private static HashMap<String, SoftReference<Bitmap>> imageCache = new HashMap<String, SoftReference<Bitmap>>();
private static Queue<Runnable> queue = new Queue<Runnable>();
// 线程池：最大50条，每次执行：1条，空闲线程结束的超时时间：180秒
private static ThreadPoolExecutor executor = new ThreadPoolExecutor(1, 20, 300, TimeUnit.SECONDS, queue);
public final static AsyncImageLoader Instance = new AsyncImageLoader();
public static void Init(final Context context) {
CachePath = SellerApplication.getInstance().mAppCacheDir + "";
ThumbnailPath = CachePath + "/thumbnails";
if (!new File(ThumbnailPath).exists())
new File(ThumbnailPath).mkdirs();
_ctx = context;
_isInit = true;
}
public static Drawable loadDrawable(final Context context, final String url, final ImageCallback imageCallback) {
if (!_isInit)
Init(context);
final String key = url;
synchronized (imageCache) {
if (imageCache.containsKey(key)) {
SoftReference<Bitmap> softReference = imageCache.get(key);
Bitmap bmp = softReference.get();
if (bmp != null && !bmp.isRecycled()) {
if (bmp == _empty) {
bmp = bmp;
} else
return new BitmapDrawable(bmp);
}
} else {
imageCache.put(key, new SoftReference<Bitmap>(_empty));
}
}
final Handler handler = new Handler() {
public void handleMessage(Message message) {
imageCallback.imageLoaded((Drawable) message.obj, url);
}
};
// 用线程池来做下载图片的任务
executor.execute(new Runnable() {
@Override
public void run() {
Bitmap bmp = loadImage(url);
if (bmp != null) {
synchronized (imageCache) {
if (imageCache.containsKey(key)) {
imageCache.put(key, new SoftReference<Bitmap>(bmp));
Message message = handler.obtainMessage(0, new BitmapDrawable(bmp));
handler.sendMessage(message);
} else {
if (!bmp.isRecycled())
bmp.recycle();
bmp = null;
System.gc();
}
}
}
}
});
return null;
}
public static Drawable loadDrawable(final Context context, final String url, final int width, final int height, final ImageCallback imageCallback) {
if (!_isInit)
Init(context);
final String key = String.format("%s_%d_%d", url, width, height);
if (imageCache.containsKey(key)) {
SoftReference<Bitmap> softReference = imageCache.get(key);
Bitmap bmp = softReference.get();
if (bmp != null && !bmp.isRecycled()) {
if (bmp == _empty) {
bmp = bmp;
} else
return new BitmapDrawable(bmp);
}
} else {
imageCache.put(key, new SoftReference<Bitmap>(_empty));
}
final Handler handler = new Handler() {
public void handleMessage(Message message) {
imageCallback.imageLoaded((Drawable) message.obj, url);
}
};
// 用线程池来做下载图片的任务
executor.execute(new Runnable() {
@Override
public void run() {
Bitmap bmp = loadImageAndScale(url, width, height);
if (imageCache.containsKey(key)) {
imageCache.put(key, new SoftReference<Bitmap>(bmp));
Message message = handler.obtainMessage(0, new BitmapDrawable(bmp));
handler.sendMessage(message);
} else {
if (!bmp.isRecycled())
bmp.recycle();
bmp = null;
System.gc();
}
}
});
return null;
}
public static void releaseDrawable(String url, int width, int height) {
log("releaseDrawable" + url);
String key = String.format("%s_%d_%d", url, width, height);
releaseDrawable(key);
}
public static void releaseDrawable(String url) {
try {
log("releaseDrawable" + url);
String key = url;
synchronized (imageCache) {
if (imageCache.containsKey(key)) {
SoftReference<Bitmap> softReference = imageCache.get(key);
imageCache.remove(key);
Bitmap bmp = softReference.get();
if (bmp != null && bmp != _empty && !bmp.isRecycled()) {
bmp.recycle();
bmp = null;
}
System.gc();
}
}
} catch (Exception e) {
String stack = RuntimeExceptionEx.GetStackTraceString(e);
}
}
private static HashMap<String, Object> _loadImageLocks = new HashMap<String, Object>();
public static Bitmap loadImage(String url) {
log("londImage:" + url);
Object lockObj = null;
synchronized (_loadImageLocks) {
if (_loadImageLocks.containsKey(url))
lockObj = _loadImageLocks.get(url);
else {
lockObj = new Object();
_loadImageLocks.put(url, lockObj);
}
}
synchronized (lockObj) {
if (isLocalImage(url))
return loadLocalImage(url);
else {
String localUrl = getCacheFileName(url);
Bitmap bmp = null;
if (new File(localUrl).exists())
bmp = loadLocalImage(localUrl);
try {
if (bmp == null)
bmp = loadHttpImage(url, 0, 0);
} catch (Throwable e) {
if (_D)
throw RuntimeExceptionEx.Create(e);
}
return bmp;
}
}
}
public static Bitmap loadImage(String url, int width, int height) {
log("londImage:" + url);
Object lockObj = null;
synchronized (_loadImageLocks) {
if (_loadImageLocks.containsKey(url))
lockObj = _loadImageLocks.get(url);
else {
lockObj = new Object();
_loadImageLocks.put(url, lockObj);
}
}
synchronized (lockObj) {
if (isLocalImage(url))
return loadLocalImage(url, width, height);
else {
String localUrl = getCacheFileName(url);
Bitmap bmp = null;
if (new File(localUrl).exists())
bmp = loadLocalImage(localUrl, width, height);
try {
if (bmp == null)
bmp = loadHttpImage(url, width, height);
} catch (Throwable e) {
if (_D)
throw RuntimeExceptionEx.Create(e);
}
return bmp;
}
}
}
private static Bitmap loadLocalImageByVideo(String url) {
log("loadLocalImageByVideo:" + url);
if (!new File(url).exists())
return null;
Bitmap bmp = ThumbnailUtils.createVideoThumbnail(url, Thumbnails.MINI_KIND);
return bmp;
}
private static Bitmap loadLocalImage(String url) {
return loadLocalImage(url, 0);
}
private static Bitmap loadLocalImage(String url, int width, int height) {
if (width == 0 && height == 0)
return loadLocalImage(url);
else
return _loadLocalImage(url, width, height);
}
private static Bitmap _loadLocalImage(String url, int width, int height) {
try {
if (!new File(url).exists())
return null;
// 获取屏幕的宽和高
/**
* 为了计算缩放的比例，我们需要获取整个图片的尺寸，而不是图片
* BitmapFactory.Options类中有一个布尔型变量inJustDecodeBounds，将其设置为true
* 这样，我们获取到的就是图片的尺寸，而不用加载图片了。 当我们设置这个值的时候，我们接着就可以从BitmapFactory.
* Options的outWidth和outHeight中获取到值
*/
BitmapFactory.Options op = new BitmapFactory.Options();
op.inJustDecodeBounds = true;
Uri uri = Uri.fromFile(new File(url));
// 由于使用了MediaStore存储，这里根据URI获取输入流的形式
Bitmap pic = BitmapFactory.decodeStream(_ctx.getContentResolver().openInputStream(uri), null, op);
int wRatio = (int) Math.ceil(op.outWidth / (float) width); // 计算宽度比例
int hRatio = (int) Math.ceil(op.outHeight / (float) height); // 计算高度比例
if (pic != null && !pic.isRecycled())
pic.recycle();
/**
* 接下来，我们就需要判断是否需要缩放以及到底对宽还是高进行缩放。 如果高和宽不是全都超出了屏幕，那么无需缩放。
* 如果高和宽都超出了屏幕大小，则如何选择缩放呢》 这需要判断wRatio和hRatio的大小
* 大的一个将被缩放，因为缩放大的时，小的应该自动进行同比率缩放。 缩放使用的还是inSampleSize变量
*/
if (wRatio > 1 && hRatio > 1) {
if (wRatio > hRatio) {
op.inSampleSize = wRatio;
} else {
op.inSampleSize = hRatio;
}
}
op.inJustDecodeBounds = false; // 注意这里，一定要设置为false，因为上面我们将其设置为true来获取图片尺寸了
try {
pic = BitmapFactory.decodeStream(_ctx.getContentResolver().openInputStream(uri), null, op);
} catch (OutOfMemoryError e) {
loadLocalImage(url, 1);
}
return pic;
} catch (Throwable e) {
throw RuntimeExceptionEx.Create(e);
}
}
private static Bitmap loadLocalImage(String url, int inSampleSize) {
log("loadLocalImage:" + url);
if (!new File(url).exists())
return null;
if (url.endsWith(".mp4") || url.endsWith(".3gp")) {
return loadLocalImageByVideo(url);
}
BitmapFactory.Options opt = new BitmapFactory.Options();
// opt.inPreferredConfig = Bitmap.Config.RGB_565;
// opt.inPurgeable = true;
// opt.inInputShareable = true;
opt.inSampleSize = inSampleSize;
// 获取资源图片
InputStream is = null;
try {
is = new FileInputStream(url);
if (is != null) {
Bitmap map = BitmapFactory.decodeStream(is, null, opt);
if (map == null)
return null;
int height = map.getHeight();
int width = map.getWidth();
if (width > 1920 || height > 1080) {
if (inSampleSize == 0)
inSampleSize = 2;
else
inSampleSize++;
if (is != null) {
try {
is.close();
} catch (Exception ex) {
}
}
map.recycle();
map = null;
return loadLocalImage(url, inSampleSize);
} else {
return map;
}
}
} catch (OutOfMemoryError e) {
if (is != null) {
try {
is.close();
} catch (Exception ex) {
}
}
System.gc();
if (inSampleSize < 50) {
if (inSampleSize == 0)
inSampleSize = 2;
else
inSampleSize++;
return loadLocalImage(url, inSampleSize);
} else
return null;
} catch (Throwable e) {
String stack = RuntimeExceptionEx.GetStackTraceString(e);
//CLLog.Error(e);
//if (_D)
// throw RuntimeExceptionEx.Create(e);
} finally {
if (is != null) {
try {
is.close();
} catch (Exception e) {
}
}
System.gc();
}
return null;
}
private static Bitmap loadHttpImage(String url, int width, int height) {
log("loadHttpImage:" + url);
String localUrl = getCacheFileName(url);
try {
HttpClient hc = new HttpClient();
if (hc.downFile(url, localUrl))
return loadLocalImage(localUrl, width, height);
else
return null;
} catch (Exception e) {
String stack = RuntimeExceptionEx.GetStackTraceString(e);
//CLLog.Error(e);
//if (_D)
// throw RuntimeExceptionEx.Create(e);
}
return null;
}
public static Bitmap loadImageAndScale(String url, int width, int height) {
log("loadImageAndScale:" + url);
String thumbnailUrl = getThumbnailFileName(url, width, height);
Bitmap bmp = loadLocalImage(url, width, height);
if (bmp == null) {
try {
bmp = loadImage(url, width, height);
} catch (Exception e) {
String stack = RuntimeExceptionEx.GetStackTraceString(e);
}
if (bmp != null) {
Bitmap bmpThumbnail = ImageHelper.ScaleAndSave(bmp, thumbnailUrl, width, height, true, true);
if (bmpThumbnail != bmp && !bmp.isRecycled())
bmp.recycle();
bmp = null;
System.gc();
bmp = bmpThumbnail;
}
}
return bmp;
}
private static boolean isLocalImage(String url) {
return new File(url).exists();
}
private static String getCacheFileName(String url) {
if (isLocalImage(url))
return url;
String localUrl = null;
if (url != null && url.length() != 0) {
localUrl = CachePath + "/" + url.substring(url.lastIndexOf("/") + 1);
}
return localUrl;
}
private static String getThumbnailFileName(String url, int width, int height) {
String thumbnailUrl = null;
if (url != null && url.length() != 0) {
thumbnailUrl = String.format("%s/%d_%d_%s", ThumbnailPath, width, height, url.substring(url.lastIndexOf("/") + 1));
}
return thumbnailUrl;
}
private static void log(String msg) {
// Console.d("AsyncImageLoader", msg);
}
public interface ImageCallback {
public void imageLoaded(Drawable imageDrawable, String imageUrl);
}
}
Android开发之一种简单的异步加载图片方法
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