Subversion Repositories SmartDukaan

/**

 * Copyright (C) 2013 The Android Open Source Project

 *

 * 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.android.volley.toolbox;

import android.content.Context;

import android.text.TextUtils;

import android.util.AttributeSet;

import android.view.ViewGroup.LayoutParams;

import android.widget.ImageView;

import com.android.volley.VolleyError;

import com.android.volley.toolbox.ImageLoader.ImageContainer;

import com.android.volley.toolbox.ImageLoader.ImageListener;

/**

 * Handles fetching an image from a URL as well as the life-cycle of the

 * associated request.

 */

public class NetworkImageView extends ImageView {

    /** 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;

    /** Current ImageContainer. (either in-flight or finished) */

    private ImageContainer mImageContainer;

    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(false);

    }

    /**

     * 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.

     * @param isInLayoutPass True if this was invoked from a layout pass, false otherwise.

     */

    void loadImageIfNecessary(final boolean isInLayoutPass) {

        int width = getWidth();

        int height = getHeight();

        ScaleType scaleType = getScaleType();

        boolean wrapWidth = false, wrapHeight = false;

        if (getLayoutParams() != null) {

            wrapWidth = getLayoutParams().width == LayoutParams.WRAP_CONTENT;

            wrapHeight = getLayoutParams().height == LayoutParams.WRAP_CONTENT;

        }

        // if the view's bounds aren't known yet, and this is not a wrap-content/wrap-content

        // view, hold off on loading the image.

        boolean isFullyWrapContent = wrapWidth && wrapHeight;

        if (width == 0 && height == 0 && !isFullyWrapContent) {

            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)) {

            if (mImageContainer != null) {

                mImageContainer.cancelRequest();

                mImageContainer = null;

            }

            setDefaultImageOrNull();

            return;

        }

        // if there was an old request in this view, check if it needs to be canceled.

        if (mImageContainer != null && mImageContainer.getRequestUrl() != null) {

            if (mImageContainer.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.

                mImageContainer.cancelRequest();

                setDefaultImageOrNull();

            }

        }

        // Calculate the max image width / height to use while ignoring WRAP_CONTENT dimens.

        int maxWidth = wrapWidth ? 0 : width;

        int maxHeight = wrapHeight ? 0 : height;

        // 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,

                new ImageListener() {

                    @Override

                    public void onErrorResponse(VolleyError error) {

                        if (mErrorImageId != 0) {

                            setImageResource(mErrorImageId);

                        }

                    }

                    @Override

                    public void onResponse(final ImageContainer response, boolean isImmediate) {

                        // If this was an immediate response that was delivered inside of a layout

                        // pass do not set the image immediately as it will trigger a requestLayout

                        // inside of a layout. Instead, defer setting the image by posting back to

                        // the main thread.

                        if (isImmediate && isInLayoutPass) {

                            post(new Runnable() {

                                @Override

                                public void run() {

                                    onResponse(response, false);

                                }

                            });

                            return;

                        }

                        if (response.getBitmap() != null) {

                            setImageBitmap(response.getBitmap());

                        } else if (mDefaultImageId != 0) {

                            setImageResource(mDefaultImageId);

                        }

                    }

                }, maxWidth, maxHeight, scaleType);

        // update the ImageContainer to be the new bitmap container.

        mImageContainer = newContainer;

    }

    private void setDefaultImageOrNull() {

        if(mDefaultImageId != 0) {

            setImageResource(mDefaultImageId);

        }

        else {

            setImageBitmap(null);

        }

    }

    @Override

    protected void onLayout(boolean changed, int left, int top, int right, int bottom) {

        super.onLayout(changed, left, top, right, bottom);

        loadImageIfNecessary(true);

    }

    @Override

    protected void onDetachedFromWindow() {

        if (mImageContainer != null) {

            // If the view was bound to an image request, cancel it and clear

            // out the image from the view.

            mImageContainer.cancelRequest();

            setImageBitmap(null);

            // also clear out the container so we can reload the image if necessary.

            mImageContainer = null;

        }

        super.onDetachedFromWindow();

    }

    @Override

    protected void drawableStateChanged() {

        super.drawableStateChanged();

        invalidate();

    }

}