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我想要一个zoom in和zoom out功能在GalleryViewandroid.I 正在尝试很多方法，但它不起作用。我在 android 上找到了另一个教程zoom in和Zoom out图像，GalleryView但尝试不起作用 任何人都可以帮助我如何实现此功能，为什么教程上的代码不起作用？

我正在尝试以下链接的本教程：

http://blog.projapps.com/?p=85

像下面的代码：

MyImageview.java

import android.content.Context;
import android.graphics.Matrix;
import android.view.MotionEvent;
import android.widget.ImageView;

public class MyImageView extends ImageView {
    public MyImageView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }

    boolean isDraggable = false;
    boolean isRight = false;
    boolean isLeft = false;

    // These matrices will be used to move and zoom image
    Matrix matrix = new Matrix();
    Matrix savedMatrix = new Matrix();

    public void setMatrix(Matrix m) {
        matrix.set(m);
    }

    public void setSavedMatrix(Matrix m) {
        savedMatrix.set(m);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (isDraggable) {
            // place pan/zoom codes here
        }
        return true;
    }
}

我的画廊.java

public class MyGallery extends Gallery {
    private PointF m_start = new PointF();
    private MyImageView imageView;

    public MyGallery(Context context) {
        super(context);
    }

    public MyGallery(Context context, AttributeSet attrSet) {
        super(context, attrSet);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent event) {
        imageView = (MyImageView) getSelectedView();
        switch (event.getAction() & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN:
                m_start.set(event.getX(), event.getY());
                break;
            case MotionEvent.ACTION_POINTER_DOWN:
                imageView.isDraggable = true;
                if (imageView.getScaleType() != ImageView.ScaleType.MATRIX) {
                    imageView.setMatrix(imageView.getImageMatrix());
                    imageView.setScaleType(ImageView.ScaleType.MATRIX);
                }
                break;
            case MotionEvent.ACTION_MOVE:
                if ((event.getX() - m_start.x < 0 && imageView.isRight) ||
                    (event.getX() - m_start.x > 0 && imageView.isLeft))
                    imageView.isDraggable = false;
                break;
        }
        if (!imageView.isDraggable) {
            onTouchEvent(event);
        }
        return super.onInterceptTouchEvent(event);
    }
}

我正在加载图像适配器类，如下代码：

public class ImageAdapter extends BaseAdapter {

        public ImageAdapter(Context c) {
            mContext = c;
        }

        public int getCount() {
            return mImageIds.length;
        }

        public Object getItem(int position) {
            return position;
        }

        public long getItemId(int position) {
            return position;
        }

        public View getView(int position, View convertView, ViewGroup parent) {

            MyImageView i = new MyImageView(mContext);
            i.setImageResource(mImageIds[position]);
            i.setScaleType(ImageView.ScaleType.FIT_XY);
            return i;            
        }

        private Context mContext;

    }

并在我的画廊类中加载图像适配器，如下面的代码：

    g = (MyGallery) findViewById(R.id.gallery);
    g.setSpacing(60);
    g.setUnselectedAlpha(1);
    g.setAdapter(new ImageAdapter(this));

此代码成功加载图像，但无法使用缩放功能！

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