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);