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August 8, 2016 18:33
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Zoomable and scrollable NetworkImageView for Volley
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/** | |
* 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. | |
* | |
* Based on NetworkImageView standard volley class (AOSP project) + Chris Banes PhotoView | |
* Modified by Jacques Giraudel | |
*/ | |
package com.android.volley.toolbox; | |
import android.content.Context; | |
import android.graphics.Bitmap; | |
import android.text.TextUtils; | |
import android.util.AttributeSet; | |
import android.widget.ImageView; | |
import com.android.volley.toolbox.ImageLoader.ImageContainer; | |
/** | |
* Handles fetching an image from a URL as well as the life-cycle of the | |
* associated request. | |
* Zoomable and scrollable Photo | |
* | |
* Needed libs : volley + Chris Banes Photo View | |
* | |
*/ | |
public class NetworkImageView extends PhotoView { | |
/** The URL of the network image to load */ | |
private String mUrl; | |
/** | |
* Resource ID of the image to be used as a placeholder until the network image is loaded. | |
*/ | |
private int mDefaultImageId; | |
/** | |
* Resource ID of the image to be used if the network response fails. | |
*/ | |
private int mErrorImageId; | |
/** Local copy of the ImageLoader. */ | |
private ImageLoader mImageLoader; | |
public NetworkImageView(Context context) { | |
this(context, null); | |
} | |
public NetworkImageView(Context context, AttributeSet attrs) { | |
this(context, attrs, 0); | |
} | |
public NetworkImageView(Context context, AttributeSet attrs, int defStyle) { | |
super(context, attrs, defStyle); | |
} | |
/** | |
* Sets URL of the image that should be loaded into this view. Note that calling this will | |
* immediately either set the cached image (if available) or the default image specified by | |
* {@link NetworkImageView#setDefaultImageResId(int)} on the view. | |
* | |
* NOTE: If applicable, {@link NetworkImageView#setDefaultImageResId(int)} and | |
* {@link NetworkImageView#setErrorImageResId(int)} should be called prior to calling | |
* this function. | |
* | |
* @param url The URL that should be loaded into this ImageView. | |
* @param imageLoader ImageLoader that will be used to make the request. | |
*/ | |
public void setImageUrl(String url, ImageLoader imageLoader) { | |
mUrl = url; | |
mImageLoader = imageLoader; | |
// The URL has potentially changed. See if we need to load it. | |
loadImageIfNecessary(); | |
} | |
/** | |
* Sets the default image resource ID to be used for this view until the attempt to load it | |
* completes. | |
*/ | |
public void setDefaultImageResId(int defaultImage) { | |
mDefaultImageId = defaultImage; | |
} | |
/** | |
* Sets the error image resource ID to be used for this view in the event that the image | |
* requested fails to load. | |
*/ | |
public void setErrorImageResId(int errorImage) { | |
mErrorImageId = errorImage; | |
} | |
/** | |
* Loads the image for the view if it isn't already loaded. | |
*/ | |
private void loadImageIfNecessary() { | |
int width = getWidth(); | |
int height = getHeight(); | |
// if the view's bounds aren't known yet, hold off on loading the image. | |
if (width == 0 && height == 0) { | |
return; | |
} | |
// if the URL to be loaded in this view is empty, cancel any old requests and clear the | |
// currently loaded image. | |
if (TextUtils.isEmpty(mUrl)) { | |
ImageContainer oldContainer = (ImageContainer) getTag(); | |
if (oldContainer != null) { | |
oldContainer.cancelRequest(); | |
setImageBitmap(null); | |
} | |
return; | |
} | |
ImageContainer oldContainer = (ImageContainer) getTag(); | |
// if there was an old request in this view, check if it needs to be canceled. | |
if (oldContainer != null && oldContainer.getRequestUrl() != null) { | |
if (oldContainer.getRequestUrl().equals(mUrl)) { | |
// if the request is from the same URL, return. | |
return; | |
} else { | |
// if there is a pre-existing request, cancel it if it's fetching a different URL. | |
oldContainer.cancelRequest(); | |
setImageBitmap(null); | |
} | |
} | |
// The pre-existing content of this view didn't match the current URL. Load the new image | |
// from the network. | |
ImageContainer newContainer = mImageLoader.get(mUrl, | |
ImageLoader.getImageListener(this, mDefaultImageId, mErrorImageId)); | |
// update the tag to be the new bitmap container. | |
setTag(newContainer); | |
// look at the contents of the new container. if there is a bitmap, load it. | |
final Bitmap bitmap = newContainer.getBitmap(); | |
if (bitmap != null) { | |
setImageBitmap(bitmap); | |
} | |
} | |
@Override | |
protected void onLayout(boolean changed, int left, int top, int right, int bottom) { | |
super.onLayout(changed, left, top, right, bottom); | |
loadImageIfNecessary(); | |
} | |
@Override | |
protected void onDetachedFromWindow() { | |
ImageContainer oldContainer = (ImageContainer) getTag(); | |
if (oldContainer != null) { | |
// If the view was bound to an image request, cancel it and clear | |
// out the image from the view. | |
oldContainer.cancelRequest(); | |
setImageBitmap(null); | |
// also clear out the tag so we can reload the image if necessary. | |
setTag(null); | |
} | |
super.onDetachedFromWindow(); | |
} | |
@Override | |
protected void drawableStateChanged() { | |
super.drawableStateChanged(); | |
invalidate(); | |
} | |
} |
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