预加载一堆图像,当所有图像都完成时 return
Preload a bunch of images, and return when all of them are complete
这里是一个相对的代码示例。基本上我想做的是预加载一些图像(因此是 for 循环)。预加载有效,但我不知道它何时完成。我知道有听众,但我不确定它们是如何工作的
当for循环中的所有图片完全加载时,是否有解决方法仅return来自该方法。这有意义吗?
public void method(){
final Activity activity = getCurrentActivity();
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
for (int i = 0; i < sources.size(); i++) {
final ReadableMap source = sources.getMap(i);
final GlideUrl glideUrl = FastImageViewConverter.glideUrl(source);
final Priority priority = FastImageViewConverter.priority(source);
Glide
.with(activity.getApplicationContext())
.load(glideUrl)
.priority(priority)
.placeholder(TRANSPARENT_DRAWABLE)
.diskCacheStrategy(DiskCacheStrategy.SOURCE)
.preload()
.listener(new RequestListener<Uri, GlideDrawable>() {
@Override public boolean onException(Exception e, Uri model, Target<GlideDrawable> target, boolean isFirstResource) {
return false;
}
@Override public boolean onResourceReady(GlideDrawable resource, Uri model, Target<GlideDrawable> target, boolean isFromMemoryCache, boolean isFirstResource) {
// easy
return false;
// impossible?
}
});
}
}
});
}
因为您知道要预加载多少张图片,也许您可以设置一个计数器,然后在 onResourceReady
中您可以递增该计数器。一旦达到您要预加载的图像数量,您就完成了,您可以继续执行其他操作
这不是最佳答案,但可能适合您的情况:)
public void method(){
final Activity activity = getCurrentActivity();
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
int counter = sources.size();
for (int i = 0; i < sources.size(); i++) {
final ReadableMap source = sources.getMap(i);
final GlideUrl glideUrl = FastImageViewConverter.glideUrl(source);
final Priority priority = FastImageViewConverter.priority(source);
Glide
.with(activity.getApplicationContext())
.load(glideUrl)
.priority(priority)
.placeholder(TRANSPARENT_DRAWABLE)
.diskCacheStrategy(DiskCacheStrategy.SOURCE)
.preload()
.listener(new RequestListener<Uri, GlideDrawable>() {
@Override public boolean onException(Exception e, Uri model, Target<GlideDrawable> target, boolean isFirstResource) {
counter--;
if counter == 0 {
return your result here
}
return false;
}
@Override public boolean onResourceReady(GlideDrawable resource, Uri model, Target<GlideDrawable> target, boolean isFromMemoryCache, boolean isFirstResource) {
counter--;
if counter == 0 {
return your result here
}
return false;
// impossible?
}
});
}
}
});
}
这里是一个相对的代码示例。基本上我想做的是预加载一些图像(因此是 for 循环)。预加载有效,但我不知道它何时完成。我知道有听众,但我不确定它们是如何工作的
当for循环中的所有图片完全加载时,是否有解决方法仅return来自该方法。这有意义吗?
public void method(){
final Activity activity = getCurrentActivity();
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
for (int i = 0; i < sources.size(); i++) {
final ReadableMap source = sources.getMap(i);
final GlideUrl glideUrl = FastImageViewConverter.glideUrl(source);
final Priority priority = FastImageViewConverter.priority(source);
Glide
.with(activity.getApplicationContext())
.load(glideUrl)
.priority(priority)
.placeholder(TRANSPARENT_DRAWABLE)
.diskCacheStrategy(DiskCacheStrategy.SOURCE)
.preload()
.listener(new RequestListener<Uri, GlideDrawable>() {
@Override public boolean onException(Exception e, Uri model, Target<GlideDrawable> target, boolean isFirstResource) {
return false;
}
@Override public boolean onResourceReady(GlideDrawable resource, Uri model, Target<GlideDrawable> target, boolean isFromMemoryCache, boolean isFirstResource) {
// easy
return false;
// impossible?
}
});
}
}
});
}
因为您知道要预加载多少张图片,也许您可以设置一个计数器,然后在 onResourceReady
中您可以递增该计数器。一旦达到您要预加载的图像数量,您就完成了,您可以继续执行其他操作
这不是最佳答案,但可能适合您的情况:)
public void method(){
final Activity activity = getCurrentActivity();
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
int counter = sources.size();
for (int i = 0; i < sources.size(); i++) {
final ReadableMap source = sources.getMap(i);
final GlideUrl glideUrl = FastImageViewConverter.glideUrl(source);
final Priority priority = FastImageViewConverter.priority(source);
Glide
.with(activity.getApplicationContext())
.load(glideUrl)
.priority(priority)
.placeholder(TRANSPARENT_DRAWABLE)
.diskCacheStrategy(DiskCacheStrategy.SOURCE)
.preload()
.listener(new RequestListener<Uri, GlideDrawable>() {
@Override public boolean onException(Exception e, Uri model, Target<GlideDrawable> target, boolean isFirstResource) {
counter--;
if counter == 0 {
return your result here
}
return false;
}
@Override public boolean onResourceReady(GlideDrawable resource, Uri model, Target<GlideDrawable> target, boolean isFromMemoryCache, boolean isFirstResource) {
counter--;
if counter == 0 {
return your result here
}
return false;
// impossible?
}
});
}
}
});
}