主体
public class ZoomImageView extends ImageView implements ScaleGestureDetector.OnScaleGestureListener, View.OnTouchListener, ViewTreeObserver.OnGlobalLayoutListener { private static final String TAG = ZoomImageView.class.getSimpleName(); public static final float SCALE_MAX = 4.0f; private static final float SCALE_MID = 2.0f; /** * 初始化时的缩放比例，如果图片宽或高大于屏幕，此值将小于0 */ private float initScale = 1.0f; private boolean once = true; /** * 用于寄存矩阵的9个值 */ private final float[] matrixValues = new float[9]; /** * 缩放的手势检测 */ private ScaleGestureDetector mScaleGestureDetector = null; private final Matrix mScaleMatrix = new Matrix(); /** * 用于双击检测 */ private GestureDetector mGestureDetector; private OnZoomImageViewSingleClickListener listener; /** * @date:2017/11/16/016 * @author:平sir * @desc: 初始化拦挡单击事件的接口对象 */ public void setListener(OnZoomImageViewSingleClickListener listener) { this.listener = listener; } public OnZoomImageViewSingleClickListener getListener() { return listener; } private boolean isAutoScale; private int mTouchSlop; private float mLastX; private float mLastY; private boolean isCanDrag; private int lastPointerCount; private boolean isCheckTopAndBottom = true; private boolean isCheckLeftAndRight = true; public ZoomImageView(Context context) { this(context, null); } public ZoomImageView(Context context, AttributeSet attrs) { super(context, attrs); super.setScaleType(ScaleType.MATRIX); mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() { @Override public boolean onDoubleTap(MotionEvent e) { if (isAutoScale) return true; float x = e.getX(); float y = e.getY(); if (getScale() < SCALE_MID) { ZoomImageView.this.postDelayed( new AutoScaleRunnable(SCALE_MID, x, y), 16); isAutoScale = true; } else if (getScale() >= SCALE_MID && getScale() < SCALE_MAX) { ZoomImageView.this.postDelayed( new AutoScaleRunnable(SCALE_MAX, x, y), 16); isAutoScale = true; } else { ZoomImageView.this.postDelayed( new AutoScaleRunnable(initScale, x, y), 16); isAutoScale = true; } return true; } }); mScaleGestureDetector = new ScaleGestureDetector(context, this); this.setOnTouchListener(this); } /** * 主动缩放的工作 * * @author zhy */ private class AutoScaleRunnable implements Runnable { static final float BIGGER = 1.07f; static final float SMALLER = 0.93f; private float mTargetScale; private float tmpScale; /** * 缩放的核心 */ private float x; private float y; /** * 传入指标缩放值，依据目标值与以后值，判断应该放大还是放大 * * @param targetScale */ public AutoScaleRunnable(float targetScale, float x, float y) { this.mTargetScale = targetScale; this.x = x; this.y = y; if (getScale() < mTargetScale) { tmpScale = BIGGER; } else { tmpScale = SMALLER; } } @Override public void run() { // 进行缩放 mScaleMatrix.postScale(tmpScale, tmpScale, x, y); checkBorderAndCenterWhenScale(); setImageMatrix(mScaleMatrix); final float currentScale = getScale(); // 如果值在非法范畴内，持续缩放 if (((tmpScale > 1f) && (currentScale < mTargetScale)) || ((tmpScale < 1f) && (mTargetScale < currentScale))) { ZoomImageView.this.postDelayed(this, 16); } else // 设置为指标的缩放比例 { final float deltaScale = mTargetScale / currentScale; mScaleMatrix.postScale(deltaScale, deltaScale, x, y); checkBorderAndCenterWhenScale(); setImageMatrix(mScaleMatrix); isAutoScale = false; } } } @SuppressLint("NewApi") @Override public boolean onScale(ScaleGestureDetector detector) { float scale = getScale(); float scaleFactor = detector.getScaleFactor(); if (getDrawable() == null) return true; /** * 缩放的范畴管制 */ if ((scale < SCALE_MAX && scaleFactor > 1.0f) || (scale > initScale && scaleFactor < 1.0f)) { /** * 最大值最小值判断 */ if (scaleFactor * scale < initScale) { scaleFactor = initScale / scale; } if (scaleFactor * scale > SCALE_MAX) { scaleFactor = SCALE_MAX / scale; } /** * 设置缩放比例 */ mScaleMatrix.postScale(scaleFactor, scaleFactor, detector.getFocusX(), detector.getFocusY()); checkBorderAndCenterWhenScale(); setImageMatrix(mScaleMatrix); } return true; } /** * 在缩放时，进行图片显示范畴的管制 */ private void checkBorderAndCenterWhenScale() { RectF rect = getMatrixRectF(); float deltaX = 0; float deltaY = 0; int width = getWidth(); int height = getHeight(); // 如果宽或高大于屏幕，则管制范畴 if (rect.width() >= width) { if (rect.left > 0) { deltaX = -rect.left; } if (rect.right < width) { deltaX = width - rect.right; } } if (rect.height() >= height) { if (rect.top > 0) { deltaY = -rect.top; } if (rect.bottom < height) { deltaY = height - rect.bottom; } } // 如果宽或高小于屏幕，则让其居中 if (rect.width() < width) { deltaX = width * 0.5f - rect.right + 0.5f * rect.width(); } if (rect.height() < height) { deltaY = height * 0.5f - rect.bottom + 0.5f * rect.height(); } mScaleMatrix.postTranslate(deltaX, deltaY); } /** * 依据以后图片的Matrix取得图片的范畴 * * @return */ private RectF getMatrixRectF() { Matrix matrix = mScaleMatrix; RectF rect = new RectF(); Drawable d = getDrawable(); if (null != d) { rect.set(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight()); matrix.mapRect(rect); } return rect; } @Override public boolean onScaleBegin(ScaleGestureDetector detector) { return true; } @Override public void onScaleEnd(ScaleGestureDetector detector) { } @Override public boolean onTouch(View v, MotionEvent event) { /** * 设置拦挡单击事件 */ mGestureDetector.setOnDoubleTapListener(new GestureDetector.OnDoubleTapListener() { @Override public boolean onSingleTapConfirmed(MotionEvent motionEvent) { if (listener != null) listener.onClick(); return false; } @Override public boolean onDoubleTap(MotionEvent e) { if (isAutoScale) return true; float x = e.getX(); float y = e.getY(); if (getScale() < SCALE_MID) { ZoomImageView.this.postDelayed( new AutoScaleRunnable(SCALE_MID, x, y), 16); isAutoScale = true; } else if (getScale() >= SCALE_MID && getScale() < SCALE_MAX) { ZoomImageView.this.postDelayed( new AutoScaleRunnable(SCALE_MAX, x, y), 16); isAutoScale = true; } else { ZoomImageView.this.postDelayed( new AutoScaleRunnable(initScale, x, y), 16); isAutoScale = true; } return true; } @Override public boolean onDoubleTapEvent(MotionEvent motionEvent) { return false; } }); if (mGestureDetector.onTouchEvent(event)) return true; mScaleGestureDetector.onTouchEvent(event); float x = 0, y = 0; // 拿到触摸点的个数 final int pointerCount = event.getPointerCount(); // 失去多个触摸点的x与y均值 for (int i = 0; i < pointerCount; i++) { x += event.getX(i); y += event.getY(i); } x = x / pointerCount; y = y / pointerCount; /** * 每当触摸点发生变化时，重置mLasX , mLastY */ if (pointerCount != lastPointerCount) { isCanDrag = false; mLastX = x; mLastY = y; } lastPointerCount = pointerCount; RectF rectF = getMatrixRectF(); switch (event.getAction()) { case MotionEvent.ACTION_DOWN: if (rectF.width() > getWidth() || rectF.height() > getHeight()) { getParent().requestDisallowInterceptTouchEvent(true); } break; case MotionEvent.ACTION_MOVE: if (rectF.width() > getWidth() || rectF.height() > getHeight()) { getParent().requestDisallowInterceptTouchEvent(true); } float dx = x - mLastX; float dy = y - mLastY; if (!isCanDrag) { isCanDrag = isCanDrag(dx, dy); } if (isCanDrag) { if (getDrawable() != null) { // if (getMatrixRectF().left == 0 && dx > 0) // { // getParent().requestDisallowInterceptTouchEvent(false); // } // // if (getMatrixRectF().right == getWidth() && dx < 0) // { // getParent().requestDisallowInterceptTouchEvent(false); // } isCheckLeftAndRight = isCheckTopAndBottom = true; // 如果宽度小于屏幕宽度，则禁止左右挪动 if (rectF.width() < getWidth()) { dx = 0; isCheckLeftAndRight = false; } // 如果高度小雨屏幕高度，则禁止高低挪动 if (rectF.height() < getHeight()) { dy = 0; isCheckTopAndBottom = false; } mScaleMatrix.postTranslate(dx, dy); checkMatrixBounds(); setImageMatrix(mScaleMatrix); } } mLastX = x; mLastY = y; break; case MotionEvent.ACTION_UP: case MotionEvent.ACTION_CANCEL: lastPointerCount = 0; break; } return true; } /** * @date:2017/11/16/016 * @author:平sir * @desc: 定义接口，用于拦挡单击事件 */ public interface OnZoomImageViewSingleClickListener { void onClick(); } /** * 取得以后的缩放比例 * * @return */ public final float getScale() { mScaleMatrix.getValues(matrixValues); return matrixValues[Matrix.MSCALE_X]; } @Override protected void onAttachedToWindow() { super.onAttachedToWindow(); getViewTreeObserver().addOnGlobalLayoutListener(this); } @SuppressWarnings("deprecation") @Override protected void onDetachedFromWindow() { super.onDetachedFromWindow(); getViewTreeObserver().removeGlobalOnLayoutListener(this); } @Override public void onGlobalLayout() { if (once) { Drawable d = getDrawable(); if (d == null) return; int width = getWidth(); int height = getHeight(); // 拿到图片的宽和高 int dw = d.getIntrinsicWidth(); int dh = d.getIntrinsicHeight(); float scale = 1.0f; // 如果图片的宽或者高大于屏幕，则缩放至屏幕的宽或者高 if (dw > width && dh <= height) { scale = width * 1.0f / dw; } if (dh > height && dw <= width) { scale = height * 1.0f / dh; } // 如果宽和高都大于屏幕，则让其按按比例适应屏幕大小 if (dw > width && dh > height) { scale = Math.min(width * 1.0f / dw, height * 1.0f / dh); } initScale = scale; mScaleMatrix.postTranslate((float) (width - dw) / 2, (float) (height - dh) / 2); mScaleMatrix.postScale(scale, scale, (float) getWidth() / 2, (float) getHeight() / 2); // 图片挪动至屏幕核心 setImageMatrix(mScaleMatrix); once = false; } } /** * 挪动时，进行边界判断，次要判断宽或高大于屏幕的 */ private void checkMatrixBounds() { RectF rect = getMatrixRectF(); float deltaX = 0, deltaY = 0; final float viewWidth = getWidth(); final float viewHeight = getHeight(); // 判断挪动或缩放后，图片显示是否超出屏幕边界 if (rect.top > 0 && isCheckTopAndBottom) { deltaY = -rect.top; } if (rect.bottom < viewHeight && isCheckTopAndBottom) { deltaY = viewHeight - rect.bottom; } if (rect.left > 0 && isCheckLeftAndRight) { deltaX = -rect.left; } if (rect.right < viewWidth && isCheckLeftAndRight) { deltaX = viewWidth - rect.right; } mScaleMatrix.postTranslate(deltaX, deltaY); } /** * 是否是推动行为 * * @param dx * @param dy * @return */ private boolean isCanDrag(float dx, float dy) { return Math.sqrt((dx * dx) + (dy * dy)) >= mTouchSlop; }}应用
<ZoomImageView android:id="@+id/iv_image" android:layout_width="match_parent" android:layout_height="match_parent" />可应用Glide
Glide.with(this).load(getResources().getDrawable(R.mipmap.ic_warm)).into(imageView);