我在网址imageView中加载图片时出现问题。图像尺寸较大或尺寸较大。
为此，我使用了ImageLoader函数。我也试过 Lazyloading 和 Picasso 。
请帮忙或建议我是什么问题，
提前谢谢。
这是我的适配器类，
public class CustomLocalAlertAdapter extends ArrayAdapter<LocalListItem>
implements AppConstants {
Activity a;
ViewHolder holder;
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
LocalListItem LocalList = getItem(position);
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(
R.layout.activity_add_local_all_alert_details, parent,
false);
holder = new ViewHolder();
holder.missingTitle = (TextView) convertView
.findViewById(R.id.missingTitle);
holder.missingDetails = (TextView) convertView
.findViewById(R.id.missingDetails);
holder.missingImage = (ImageView) convertView
.findViewById(R.id.missingImage);
holder.suspectImage = (ImageView) convertView
.findViewById(R.id.suspectImage);
// Year, Make, Model, Color, LisencePlateNo, Vin, Place
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
String allAlertSuspectDetails = "";
String allAlertVehicleDetails = "";
String allAlertPersonDetails = "";
if (LocalList.title.equalsIgnoreCase("missing_vehicle_report")) {
allAlertPersonDetails = "";
allAlertSuspectDetails = "";
holder.missingTitle.setText("Missing Vehicle");
allAlertVehicleDetails = "\n" + "Year: " + LocalList.Year + "\n"
+ "Make: " + LocalList.Make + "\n" + "Model: "
+ LocalList.Model + "\n" + "Color: " + LocalList.Color
+ "\n" + "LisencePlateNo: " + LocalList.LisencePlateNo
+ "\n" + "Vin: " + LocalList.Vin + "\n" + "Place: "
+ LocalList.Place;
holder.suspectImage.setVisibility(View.GONE);
} else {
holder.suspectImage.setVisibility(View.VISIBLE);
allAlertVehicleDetails = "";
holder.missingTitle.setText("Missing Person");
allAlertPersonDetails = "\n" + "Name: " + LocalList.personName
+ "\n" + "Height: " + LocalList.height + "\n"
+ "Unique Mark: " + LocalList.uniqueMark + "\n"
+ "Last seen: " + LocalList.lastSeen + "\n"
+ "Date Missing: " + LocalList.dateMissing + "\n"
+ "Police department: " + LocalList.policeDept + "\n"
+ "Police dept.phone: " + LocalList.policePhn + "\n" + "\n";
if (LocalList.suspectName.equalsIgnoreCase("")
|| LocalList.suspectName.equalsIgnoreCase("null")
|| LocalList.suspectName.equalsIgnoreCase(" ")) {
allAlertSuspectDetails = "";
holder.suspectImage.setVisibility(View.GONE);
} else {
allAlertSuspectDetails = "Suspect name: "
+ LocalList.suspectName + "\n" + "Vehicle Color: "
+ LocalList.vehicleColor + "\n" + "Vehicle Year: "
+ LocalList.vehicleYear + "\n" + "Vehicle Make: "
+ LocalList.vehicleMake + "\n" + "Vehicle Model: "
+ LocalList.vehicleModel;
}
}
holder.missingDetails.setText(allAlertVehicleDetails
+ allAlertPersonDetails + allAlertSuspectDetails);
ImageLoader imgloader = new ImageLoader(a.getApplicationContext());
try {
int loader = R.drawable.loader;
int imgURL = R.drawable.no_image_found;
if (LocalList.title.equalsIgnoreCase("missing_vehicle_report")) {
imgloader.DisplayImage(LocalList.vehicleImg, loader,
holder.missingImage);
} else {
imgloader.DisplayImage(LocalList.personImage, loader,
holder.missingImage);
imgloader.DisplayImage(LocalList.suspectImage, loader,
holder.suspectImage);
}
} catch (Exception e) {
e.printStackTrace();
}
return convertView;
}
public static class ViewHolder {
TextView missingTitle;
TextView missingDetails;
ImageView missingImage;
ImageView suspectImage;
}
public CustomLocalAlertAdapter(Context context,
ArrayList<LocalListItem> ListItem, Activity a) {
super(context, 0, ListItem);
// TODO Auto-generated constructor stub
this.a = a;
}
}
这是ImageLoader函数，
public class ImageLoader {
MemoryCache memoryCache = new MemoryCache();
FileCache fileCache;
private Map<ImageView, String> imageViews = Collections
.synchronizedMap(new WeakHashMap<ImageView, String>());
ExecutorService executorService;
public ImageLoader(Context context) {
fileCache = new FileCache(context);
executorService = Executors.newFixedThreadPool(5);
}
int stub_id = R.drawable.ic_launcher;
public void DisplayImage(String url, int loader, ImageView imageView) {
stub_id = loader;
imageViews.put(imageView, url);
Bitmap bitmap = memoryCache.get(url);
if (bitmap != null)
imageView.setImageBitmap(bitmap);
else {
queuePhoto(url, imageView);
imageView.setImageResource(loader);
}
}
private void queuePhoto(String url, ImageView imageView) {
PhotoToLoad p = new PhotoToLoad(url, imageView);
executorService.submit(new PhotosLoader(p));
}
private Bitmap getBitmap(String url) {
File f = fileCache.getFile(url);
// from SD cache
Bitmap b = decodeFile(f);
if (b != null)
return b;
// from web
try {
Bitmap bitmap = null;
URL imageUrl = new URL(url);
HttpURLConnection conn = (HttpURLConnection) imageUrl
.openConnection();
conn.setConnectTimeout(70000);
conn.setReadTimeout(100000);
conn.setInstanceFollowRedirects(true);
InputStream is = conn.getInputStream();
OutputStream os = new FileOutputStream(f);
Utils.CopyStream(is, os);
os.close();
bitmap = decodeFile(f);
return bitmap;
} catch (Exception ex) {
ex.printStackTrace();
return null;
}
}
// decodes image and scales it to reduce memory consumption
private Bitmap decodeFile(File f) {
try {
// decode image size
BitmapFactory.Options o = new BitmapFactory.Options();
o.inJustDecodeBounds = true;
BitmapFactory.decodeStream(new FileInputStream(f), null, o);
// Find the correct scale value. It should be the power of 2.
final int REQUIRED_SIZE = 40;
int width_tmp = o.outWidth, height_tmp = o.outHeight;
int scale = 1;
while (true) {
if (width_tmp / 2 < REQUIRED_SIZE
|| height_tmp / 2 < REQUIRED_SIZE)
break;
width_tmp /= 2;
height_tmp /= 2;
scale *= 2;
}
// decode with inSampleSize
BitmapFactory.Options o2 = new BitmapFactory.Options();
o2.inSampleSize = scale;
return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
} catch (FileNotFoundException e) {
}
return null;
}
// Task for the queue
private class PhotoToLoad {
public String url;
public ImageView imageView;
public PhotoToLoad(String u, ImageView i) {
url = u;
imageView = i;
}
}
class PhotosLoader implements Runnable {
PhotoToLoad photoToLoad;
PhotosLoader(PhotoToLoad photoToLoad) {
this.photoToLoad = photoToLoad;
}
@Override
public void run() {
if (imageViewReused(photoToLoad))
return;
Bitmap bmp = getBitmap(photoToLoad.url);
memoryCache.put(photoToLoad.url, bmp);
if (imageViewReused(photoToLoad))
return;
BitmapDisplayer bd = new BitmapDisplayer(bmp, photoToLoad);
Activity a = (Activity) photoToLoad.imageView.getContext();
a.runOnUiThread(bd);
}
}
boolean imageViewReused(PhotoToLoad photoToLoad) {
String tag = imageViews.get(photoToLoad.imageView);
if (tag == null || !tag.equals(photoToLoad.url))
return true;
return false;
}
// Used to display bitmap in the UI thread
class BitmapDisplayer implements Runnable {
Bitmap bitmap;
PhotoToLoad photoToLoad;
public BitmapDisplayer(Bitmap b, PhotoToLoad p) {
bitmap = b;
photoToLoad = p;
}
public void run() {
if (imageViewReused(photoToLoad))
return;
if (bitmap != null)
photoToLoad.imageView.setImageBitmap(bitmap);
else
photoToLoad.imageView.setImageResource(stub_id);
}
}
public void clearCache() {
memoryCache.clear();
fileCache.clear();
}
}
答案 0 :(得分：0)
听起来你有一个缓存问题。很难弄清楚问题出在哪里。尝试使用谷歌的排球。您只需要几行代码就可以为您处理缓存。看看this回答。
编辑：
首先导入Volley库。然后：
用NetworkImageView替换ImageView：
<com.android.volley.toolbox.NetworkImageView
android:id="@+id/networkImageView"
android:layout_width="150dp"
android:layout_height="170dp"
android:layout_centerHorizontal="true" />
这就是你设置图像的方式：
// Get the NetworkImageView that will display the image.
mNetworkImageView = (NetworkImageView) findViewById(R.id.networkImageView);
ImageView mImageView;
String url = "http://i.imgur.com/7spzG.png";
// Retrieves an image specified by the URL, displays it in the UI.
ImageRequest request = new ImageRequest(url,
new Response.Listener<Bitmap>() {
@Override
public void onResponse(Bitmap bitmap) {
mImageView.setImageBitmap(bitmap);
}
}, 0, 0, null,
new Response.ErrorListener() {
public void onErrorResponse(VolleyError error) {
mImageView.setImageResource(R.drawable.image_load_error);
}
});
// Get the ImageLoader through your singleton class.
mImageLoader = MySingleton.getInstance(this).getImageLoader();
// Set the URL of the image that should be loaded into this view, and
// specify the ImageLoader that will be used to make the request.
mNetworkImageView.setImageUrl(IMAGE_URL, mImageLoader);