最完美的ZoomImageView，可根据点击/多指触控 放大,放小的ImageVIew

package com.brandsh.tiaoshi.widget;import android.annotation.SuppressLint;import android.content.Context;import android.graphics.Bitmap;import android.graphics.Matrix;import android.graphics.RectF;import android.graphics.drawable.Drawable;import android.util.AttributeSet;import android.util.Log;import android.view.GestureDetector;import android.view.MotionEvent;import android.view.ScaleGestureDetector;import android.view.View;import android.view.ViewConfiguration;import android.view.ViewTreeObserver;import android.widget.ImageView;import java.util.ArrayList;import java.util.List;/** * 可根据点击/多指触控 放大,放小的ImageVIew * @author ZHAO * @date 2016年08月17日15:10:33 */public class ZoomImageView extends ImageView implements ViewTreeObserver.OnGlobalLayoutListener        , View.OnTouchListener, ScaleGestureDetector.OnScaleGestureListener {    private static final String TAG = "ZoomImageView";    private boolean isInit;    /**     * 缩放工具     */    private Matrix mMatrix;    /**     * 缩放的最小值     */    private float mMinScale;    /**     * 缩放的中间值     */    private float mMidScale;    /**     * 缩放的最大值     */    private float mMaxScale;    /**     * 多点手势触 控缩放比率分析器     */    private ScaleGestureDetector mScaleGestureDetector;    /**     * 记录上一次多点触控的数量     */    private int mLastPointereCount;    private float mLastX;    private float mLastY;    private int mTouchSlop;    private boolean isCanDrag;    private boolean isCheckLeftAndRight;    private boolean isCheckTopAndBottom;    //实现双击放大与缩小    private GestureDetector mGestureDetector;    private boolean isScaleing;    private List<MotionEvent> events;    private OnClickListener onClickListener;    private int arae_img_id = -1;    public ZoomImageView(Context context) {        this(context, null);    }    public ZoomImageView(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public ZoomImageView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        setScaleType(ScaleType.MATRIX);        mMatrix = new Matrix();        mScaleGestureDetector = new ScaleGestureDetector(context, this);        mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {            @Override            public boolean onDoubleTap(MotionEvent e) {                if (isScaleing || getScale() >= mMaxScale)                    return true;                isScaleing = true;                float x = e.getX();                float y = e.getY();                if (getScale() < mMidScale) {                    postDelayed(new AutoScaleRunnable(mMidScale, x, y), 16);                } else {                    postDelayed(new AutoScaleRunnable(mMinScale, x, y), 16);                }                return true;            }            @Override            public boolean onSingleTapConfirmed(MotionEvent e) {                if (onClickListener != null) {                    onClickListener.onClick(ZoomImageView.this);                    return true;                }                return false;            }        });        setOnTouchListener(this);        mTouchSlop = ViewConfiguration.get(context).getScaledTouchSlop();        events = new ArrayList<>();    }    private class AutoScaleRunnable implements Runnable {        /**         * 要缩放的目标值         */        private float mTargetScale;        private float x; //缩放的中心点x        private float y; //缩放的中心点y        private float tmpScale;        private final float BIGGER = 1.07f;        private final float SMALL = 0.93f;        public AutoScaleRunnable(float mTargetScale, float x, float y) {            this.mTargetScale = mTargetScale;            this.x = x;            this.y = y;            if (getScale() < mTargetScale) {                tmpScale = BIGGER;            } else {                tmpScale = SMALL;            }        }        @Override        public void run() {            mMatrix.postScale(tmpScale, tmpScale, x, y);            checkBorderAndCenterWhenScale();            setImageMatrix(mMatrix);            float currentScale = getScale();            if ((tmpScale > 1.0f && currentScale < mTargetScale)                    || (tmpScale < 1.0f && currentScale > mTargetScale)) {                postDelayed(this, 16);            } else {                float scale = mTargetScale / currentScale;                mMatrix.postScale(scale, scale, x, y);                checkBorderAndCenterWhenScale();                setImageMatrix(mMatrix);                isScaleing = false;            }        }    }    @Override    protected void onAttachedToWindow() {        super.onAttachedToWindow();        log("注册了OnGlobalLayoutListener");        getViewTreeObserver().addOnGlobalLayoutListener(this);    }    @SuppressLint("NewApi")    @Override    @SuppressWarnings("deprecation")    protected void onDetachedFromWindow() {        super.onDetachedFromWindow();        getViewTreeObserver().removeOnGlobalLayoutListener(this);    }    @Override    public void onGlobalLayout() {        if (getDrawable() == null || getWidth() == 0 || getHeight() == 0) return;        if (!isInit) {            int width = getWidth();            int height = getHeight();            float screenWeight = height * 1.0f / width;            int imageH = getDrawable().getIntrinsicHeight(); // 图片高度            int imageW = getDrawable().getIntrinsicWidth(); // 图片宽度            float imageWeight = imageH * 1.0f / imageW;            //如果当前屏幕高宽比 大于等于 图片高宽比,就缩放图片            if (screenWeight >= imageWeight) {                float scale = 1.0f;                //图片比当前View宽,但是比当前View矮                if (imageW > width && imageH < height) {                    scale = width * 1.0f / imageW; //根据宽度缩放                }                //图片比当前View窄,但是比当前View高                if (imageH > height && imageW < width) {                    scale = height * 1.0f / imageH; //根据高度缩放                }                //图片高宽都大于当前View,那么就根据最小的缩放值来缩放                if (imageH > height && imageW > width) {                    scale = Math.min(width * 1.0f / imageW, height * 1.0f / imageH);                    log("max scale:" + scale);                }                if (imageH < height && imageW < width) {                    scale = Math.min(width * 1.0f / imageW, height * 1.0f / imageH);                    log("min scale:" + scale);                }                /**                 * 设置缩放比率                 */                mMinScale = scale;                mMidScale = mMinScale * 2;                mMaxScale = mMinScale * 4;                /**                 * 把图片移动到中心点去                 */                int dx = getWidth() / 2 - imageW / 2;                int dy = getHeight() / 2 - imageH / 2;                /**                 * 设置缩放(全图浏览模式,用最小的缩放比率去查看图片就好了)/移动位置                 */                mMatrix.postTranslate(dx, dy);                mMatrix.postScale(mMinScale, mMinScale, width / 2, height / 2);            } else {                //将宽度缩放至屏幕比例缩放(长图,全图预览)                float scale = width * 1.0f / imageW;                /**                 * 设置缩放比率                 */                mMaxScale = scale;                mMidScale = mMaxScale / 2;                mMinScale = mMaxScale / 4;                //因为是长图浏览,所以用最大的缩放比率去加载长图                //mMatrix.postTranslate(0, 0);                mMatrix.postScale(mMaxScale, mMaxScale, 0, 0);            }            setImageMatrix(mMatrix);            isInit = true;        }    }    /**     * 是否是Debug模式     */    private static boolean IS_DEBUG = true;    /**     * 打印日志     *     * @param value 要打印的日志     */    public static void log(String value) {        if (IS_DEBUG)            Log.w(TAG, value);    }    /**     * 设置图片URL,自动下载并加载     * 请注意:     * 这里的图片下载并加载,未使用缩放!会用原图加载.     * 请注意OOM异常!     *     * @param url 图片URL     *///    public void setImageForUrl(String url) {//        reSetState();//        new ImageDownLoad(getContext(), url)//                .into(this)//                .placeholder(arae_img_id)//                .start();//    }    /**     * 设置初始化状态为false     */    public void reSetState() {        isInit = false;        setTag(null);        mMatrix.reset();    }    @Override    public boolean onTouch(View view, MotionEvent motionEvent) {        if (mGestureDetector.onTouchEvent(motionEvent))            return true;        //将触摸事件传递给ScaleGestureDetector        if (motionEvent.getPointerCount() > 1)            mScaleGestureDetector.onTouchEvent(motionEvent);        float x = 0;        float y = 0;        int pointerCount = motionEvent.getPointerCount();        for (int i = 0; i < pointerCount; i++) {            x += motionEvent.getX(i);            y += motionEvent.getY(i);        }        x /= pointerCount;        y /= pointerCount;        if (mLastPointereCount != pointerCount) {            isCanDrag = false;            mLastX = x;            mLastY = y;        }        mLastPointereCount = pointerCount;        switch (motionEvent.getAction()) {            case MotionEvent.ACTION_DOWN: {                RectF rectF = getMatrixRectF();                if ((rectF.width() > getWidth() + 0.01f || (rectF.height() > getHeight() + 0.01f))) {                    if ((rectF.right != getWidth()) && (rectF.left != 0)) {                        try {                            getParent().requestDisallowInterceptTouchEvent(true);                        } catch (Exception e) {                            log(e.toString());                        }                    }                }                break;            }            case MotionEvent.ACTION_MOVE: {                float dx = x - mLastX;                float dy = y - mLastY;                if (!isCanDrag) {                    isCanDrag = isMoveAction(dx, dy);                }                if (isCanDrag) {                    RectF rectF = getMatrixRectF();                    if (getDrawable() != null) {                        isCheckLeftAndRight = isCheckTopAndBottom = true;                        if (rectF.width() <= getWidth()) {                            isCheckLeftAndRight = false;                            dx = 0;                        }                        if (rectF.height() <= getHeight()) {                            isCheckTopAndBottom = false;                            dy = 0;                        }                        mMatrix.postTranslate(dx, dy);                        checkBorderWhenTranslate();                        setImageMatrix(mMatrix);                    }                }                mLastX = x;                mLastY = y;                RectF rect = getMatrixRectF();                if ((rect.width() > getWidth() + 0.01f || (rect.height() > getHeight() + 0.01f))) {                    if ((rect.right != getWidth()) && (rect.left != 0)) {                        try {                            getParent().requestDisallowInterceptTouchEvent(true);                        } catch (Exception e) {                            log(e.toString());                        }                    }                }                break;            }            case MotionEvent.ACTION_CANCEL:            case MotionEvent.ACTION_UP: {                mLastPointereCount = 0;                break;            }        }        return true;    }    /**     * 在移动图片的时候进行边界检查     */    private void checkBorderWhenTranslate() {        RectF rectF = getMatrixRectF();        float deltaX = 0;        float deltaY = 0;        int width = getWidth();        int height = getHeight();        if (rectF.top > 0 && isCheckTopAndBottom) {            deltaY = -rectF.top;        }        if (rectF.bottom < height && isCheckTopAndBottom) {            deltaY = height - rectF.bottom;        }        if (rectF.left > 0 && isCheckLeftAndRight) {            deltaX = -rectF.left;        }        if (rectF.right < width && isCheckLeftAndRight) {            deltaX = width - rectF.right;        }        mMatrix.postTranslate(deltaX, deltaY);        setImageMatrix(mMatrix);    }    /**     * 判断是否足以触发移动事件     *     * @param dx     * @param dy     * @return     */    private boolean isMoveAction(float dx, float dy) {        return Math.sqrt(dx * dx + dy * dy) > mTouchSlop;    }    @Override    public boolean onScale(ScaleGestureDetector detector) {        float scaleFactor = detector.getScaleFactor();//获取用户手势判断出来的缩放值        float scale = getScale();        /**         * 没有图片         */        if (getDrawable() == null) return true;        //缩放范围控制        if ((scale < mMaxScale && scaleFactor > 1.0f) || (scale > mMinScale && scaleFactor < 1.0f)) {            if (scaleFactor * scale < mMinScale) {                scaleFactor = mMinScale / scale;            }            if (scale * scaleFactor > mMaxScale) {                scaleFactor = mMaxScale / scale;            }            mMatrix.postScale(scaleFactor, scaleFactor, detector.getFocusX(), detector.getFocusY());            checkBorderAndCenterWhenScale();            setImageMatrix(mMatrix);        }        return true;    }    /**     * 在缩放的时候进行边界,位置 检查     */    private void checkBorderAndCenterWhenScale() {        RectF rectF = getMatrixRectF();        float deltaX = 0;        float deltaY = 0;        int width = getWidth();        int height = getHeight();        if (rectF.width() >= width) {            if (rectF.left > 0)                deltaX = -rectF.left;            if (rectF.right < width)                deltaX = width - rectF.right;        }        if (rectF.height() >= height) {            if (rectF.top > 0)                deltaY = 0;            if (rectF.bottom < height)                deltaY = height - rectF.bottom;        }        if (rectF.width() < width) {            deltaX = width / 2f - rectF.right + rectF.width() / 2;        }        if (rectF.height() < height) {            deltaY = height / 2f - rectF.bottom + rectF.height() / 2;        }        mMatrix.postTranslate(deltaX, deltaY);        setImageMatrix(mMatrix);    }    /**     * 获取图片放大缩小后的宽高/top/left/right/bottom     *     * @return     */    private RectF getMatrixRectF() {        RectF rectF = new RectF();        Drawable drawable = getDrawable();        if (drawable != null) {            rectF.set(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());            mMatrix.mapRect(rectF);        }        return rectF;    }    @Override    public boolean onScaleBegin(ScaleGestureDetector scaleGestureDetector) {        return true; //缩放开始,返回true 用于接收后续时间    }    @Override    public void onScaleEnd(ScaleGestureDetector scaleGestureDetector) {    }    /**     * 获取当前的缩放比率     *     * @return     */    private float getScale() {        float[] values = new float[9];        mMatrix.getValues(values);        return values[Matrix.MSCALE_X];    }    @Override    public void setImageBitmap(Bitmap bm) {        reSetState();        super.setImageBitmap(bm);    }    @Override    public void setImageResource(int resId) {        reSetState();        super.setImageResource(resId);    }    @Override    public void setOnClickListener(OnClickListener l) {        this.onClickListener = l;    }    /**     * 设置加载中的占位图     *     * @param resID     */    public void placeholder(int resID) {        this.arae_img_id = resID;    }}