android - 缩放时更改 ImageView 的大小

Question

我正在使用 chrisbanes PhotoView 来实现捏合缩放。图像在捏合和双击时缩放，但我看不到我的图像在缩放时拉伸(stretch)到全屏。在缩放时它看起来图像在一个框和部分内缩放图像的缩放在缩放时消失...我如何实现图像缩放以便图像的高度在缩放时增加？我正在使用 NetworkImageView(Volley 库)。

NetworkImageView imageView;
 PhotoViewAttacher mAttacher;

                imageView = (NetworkImageView) mImgPagerView.findViewById(R.id.imageitem);

                mAttacher = new PhotoViewAttacher(imageView);

NetworkImageView.java(来自 Volley 库)

     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;

public class NetwrokImageView 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;
    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();
    }
}

构建.gradle

compile 'com.github.chrisbanes.photoview:library:+'

xml

<com.xyz.NetworkImageView
            android:id="@+id/imageitem"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:scaleType="matrix"
            android:layout_gravity="center"
            android:adjustViewBounds="true"
            android:background="@drawable/image_loading" />

ImageView 在 FrameLayout 里面

    <FrameLayout
        android:id="@+id/image_holder"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:background="@color/black"
        >

缩放前的图像 缩放后的图像

Answer 1

如果你卡住了，最好尝试不同的方法

您可以在下面找到由 Jason Polites 创建的类的链接，该类允许您处理自定义 ImageView 上的缩放:https://github.com/jasonpolites/gesture-imageview .

只需将此包包含到您的应用程序中，然后您就可以在您的 XML 文件中使用自定义 GestureImaveView:

<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:gesture-image="http://schemas.polites.com/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">

<com.polites.android.GestureImageView
    android:id="@+id/image"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:src="@drawable/image"
    gesture-image:min-scale="0.1"
    gesture-image:max-scale="10.0"
    gesture-image:strict="false"/>

这个类处理捏缩放，但也双击。

答案归功于 Yoann :)