我想在 Imageview 上实现 Pinch Zoom，在 View Pager 中类似于 Default Android Gallery。我在 GitHub 上找到了多个来源，但缩放和滑动仅适用于第一张图片。
我尝试过的：
1.) TouchImageView
2.) PhotoView
以上所有链接都适用于单个图像视图。但是当涉及到 View 寻呼机中的图像时，它们会出现一些故障，并且仅适用于 View Pager 中的第一张图像。当我们在视图寻呼机中滚动到第 3 个第 4 个图像时，如果图像被缩放，则拖动功能无法按预期工作。
如果有人知道这样做的好图书馆，请给我他们的链接。
【问题讨论】：
标签： android imageview android-viewpager pinchzoom
编辑 2：示例代码已推送到 TouchImageView 的主分支。这是link to the example activity 和link to the ExtendedViewPager。
编辑：添加了将示例链接适配到 TouchImageView 的代码。注意：您将需要最新的代码，该代码当前位于 dev 分支中。将来，这将包含在 v1.2.0 中。如果 TouchImageView 覆盖 canScrollHorizontally，你知道你有最新的代码。
第 1 步：扩展 ViewPager 并覆盖 canScroll 以调用 canScrollHorizontallyFroyo。
public class ExtendedViewPager extends ViewPager {
public ExtendedViewPager(Context context) {
super(context);
}
public ExtendedViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
if (v instanceof TouchImageView) {
return ((TouchImageView) v).canScrollHorizontallyFroyo(-dx);
} else {
return super.canScroll(v, checkV, dx, x, y);
}
}
}
第二步：修改TouchImageView，添加canScrollHorizontallyFroyo：
public boolean canScrollHorizontallyFroyo(int direction) {
return canScrollHorizontally(direction);
}
第 3 步：您的活动
public class TouchImageViewActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ExtendedViewPager mViewPager = (ExtendedViewPager) findViewById(R.id.view_pager);
setContentView(mViewPager);
mViewPager.setAdapter(new TouchImageAdapter());
}
static class TouchImageAdapter extends PagerAdapter {
private static int[] images = { R.drawable.img1, R.drawable.img2, R.drawable.img3 };
@Override
public int getCount() {
return images.length;
}
@Override
public View instantiateItem(ViewGroup container, int position) {
TouchImageView img = new TouchImageView(container.getContext());
img.setImageResource(images[position]);
container.addView(img, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
return img;
}
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
}
}
}
第四步： main.xml
<com.example.touch.ExtendedViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/view_pager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
TouchImageView 实际上是我的项目。我目前在dev branch 中有a fix 用于与ViewPagers 集成，它将在即将发布的版本中推送到master。不幸的是，此修复仅适用于 API 14 及更高版本，因为蜂窝和更早版本不调用 canScrollHorizontally。如果您需要支持较旧的 API，则需要在 ViewPager 中实施解决方法。 Here is an example.
【讨论】：
我用ImageViewZoom 库找到了很好的解决方案。 为了在 ViewPager 中滚动缩放图像，我创建了自己的 ViewPager：
public class ExtendedViewPager extends ViewPager {
public ExtendedViewPager(Context context) {
super(context);
}
public ExtendedViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
if (v instanceof ImageViewTouch) {
return ((ImageViewTouch) v).canScroll(dx);
} else {
return super.canScroll(v, checkV, dx, x, y);
}
}
}
【讨论】：
在对上述解决方案进行了几个小时的测试后，我终于找到了很棒的 Subsampling Scale Image View 库，它甚至可以与 Android 支持包中的标准 ViewPager 一起使用。
【讨论】：
我使用ImageViewZoom Library 的解决方案基于此自定义 ViewPager：
public class ImageViewTouchViewPager extends ViewPager {
public ImageViewTouchViewPager(Context context) {
super(context);
}
public ImageViewTouchViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
if (v instanceof ImageViewTouch) {
ImageViewTouch imageViewTouch = (ImageViewTouch)v;
if (imageViewTouch.getScale() == imageViewTouch.getMinScale()) {
return super.canScroll(v, checkV, dx, x, y);
}
return imageViewTouchCanScroll(imageViewTouch, dx);
} else {
return super.canScroll(v, checkV, dx, x, y);
}
}
/**
* Determines whether the ImageViewTouch can be scrolled.
*
* @param direction - positive direction value means scroll from right to left,
* negative value means scroll from left to right
* @return true if there is some more place to scroll, false - otherwise.
*/
private boolean imageViewTouchCanScroll(ImageViewTouch v, int direction){
RectF bitmapRect = v.getBitmapRect();
Rect imageViewRect = new Rect();
getGlobalVisibleRect(imageViewRect);
if (null == bitmapRect) {
return false;
}
if (direction < 0) {
return Math.abs(bitmapRect.right - imageViewRect.right) > 1.0f;
}else {
return Math.abs(bitmapRect.left - imageViewRect.left) > 1.0f;
}
}
}
【讨论】：
我更正了之前的解决方案。当 ImageViewTouch 为缩放模式时，您可以滚动页面。
public class ImageViewTouchViewPager extends ViewPager {
public ImageViewTouchViewPager(Context context) {
super(context);
}
public ImageViewTouchViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) {
if (v instanceof ImageViewTouch) {
ImageViewTouch imageViewTouch = (ImageViewTouch)v;
return imageViewTouchCanScroll(imageViewTouch, dx);
} else {
return super.canScroll(v, checkV, dx, x, y);
}
}
/**
* Determines whether the ImageViewTouch can be scrolled.
*
* @param direction - positive direction value means scroll from right to left,
* negative value means scroll from left to right
* @return true if there is some more place to scroll, false - otherwise.
*/
private boolean imageViewTouchCanScroll(ImageViewTouch imageViewTouch, int direction){
int widthScreen = getWidthScreen();
RectF bitmapRect = imageViewTouch.getBitmapRect();
Rect imageViewRect = new Rect();
getGlobalVisibleRect(imageViewRect);
int widthBitmapViewTouch = (int)bitmapRect.width();
if (null == bitmapRect) {
return false;
}
if(widthBitmapViewTouch < widthScreen){
return false;
}
if (direction < 0) {
return Math.abs(bitmapRect.right - imageViewRect.right) > 1.0f;
}else {
return Math.abs(bitmapRect.left - imageViewRect.left) > 1.0f;
}
}
private int getWidthScreen(){
WindowManager wm = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
Point size = new Point();
display.getSize(size);
return size.x;
}
}
【讨论】：
对于那些在图像处于缩放状态时努力禁用查看器并在图像处于原始状态时启用的人。正如迈克所回答的那样，我刚刚做了一些更改。
import android.content.Context
import android.util.AttributeSet
import android.util.Log
import android.view.MotionEvent
import android.view.View
import android.view.ViewGroup
import androidx.viewpager.widget.ViewPager
class DCExtendedViewPager : ViewPager {
private val TAG = DCExtendedViewPager::class.java.simpleName
private var onImageState: OnImageState? = null
private var touchImageViewCustom: DCTouchImageViewLatest? = null
var isScroll: Boolean = true
interface OnImageState {
fun checkImageState(isImageInOriginalState: Boolean)
}
constructor(context: Context) : super(context)
constructor(context: Context, attrs: AttributeSet) : super(context, attrs)
override fun canScroll(view: View, checkV: Boolean, dx: Int, x: Int, y: Int): Boolean {
return if (view is DCTouchImageViewLatest) {
// touchImageView=view
// canScrollHorizontally is not supported for Api < 14. To get around this issue,
// ViewPager is extended and canScrollHorizontallyFroyo, a wrapper around
// canScrollHorizontally supporting Api >= 8, is called.
Log.e("ExtendedViewPager", "canScroll zoomedRect" + view.zoomedRect)
view.canScrollHorizontallyFroyo(-dx)
} else {
super.canScroll(view, checkV, dx, x, y)
}
}
override fun onTouchEvent(event: MotionEvent): Boolean {
Log.e(TAG, "onTouchEventenable" + isScroll)
return if (isScroll) {
super.onTouchEvent(event)
} else false
}
override fun onInterceptTouchEvent(event: MotionEvent): Boolean {
Log.e(TAG, "onInterceptTouchEvent")
Log.e(TAG, "currenrLayoutView called")
val currenrLayoutView = getCurrentParentView()
getTouchImageViewInstance(currenrLayoutView!!)
return if (isScroll) {
super.onInterceptTouchEvent(event)
} else false
}
fun isViewPagerScrollValid(): Boolean {
Log.e(TAG, "getFocusedChild()" + focusedChild)
val currenrLayoutView = getCurrentParentView()
var zoomRect = getTouchImageViewInstance(currenrLayoutView!!)?.zoomedRect
var orgzoomRect = getTouchImageViewInstance(currenrLayoutView)?.originalRectF
Log.e(TAG, "onInterceptTouchEvent zoomRect" + zoomRect)
Log.e(TAG, "onInterceptTouchEvent orgzoomRect" + orgzoomRect)
Log.e(TAG, "onInterceptTouchEvent onImageState" + onImageState)
var scrollEnable = (zoomRect == orgzoomRect)
// postLater(getTouchImageViewInstance(currenrLayoutView!!)!!)
onImageState?.checkImageState(scrollEnable)
Log.e(TAG, "onInterceptTouchEvent" + scrollEnable)
return scrollEnable
}
fun setImageStateListner(onImageState: OnImageState) {
this.onImageState = onImageState
}
fun getTouchImageViewInstance(accessingView: View): DCTouchImageViewLatest? {
if (touchImageViewCustom == null) {
try {
for (index in 0 until (accessingView as ViewGroup).childCount) {
var nextChild = accessingView.getChildAt(index)
Log.e(TAG, "nextChild" + nextChild)
if (nextChild is ViewGroup) {
getTouchImageViewInstance(nextChild)
} else if (nextChild is View) {
if (nextChild is DCTouchImageViewLatest) {
touchImageViewCustom = nextChild
setListner()
break
}
}
}
} catch (ex: Exception) {
ex.printStackTrace()
}
}
Log.e(TAG, "getTouchImageViewInstance" + touchImageViewCustom)
return touchImageViewCustom
}
private fun setListner() {
touchImageViewCustom?.setOnDCTouchImageViewLatestListener(object : DCTouchImageViewLatest.OnDCTouchImageViewLatestListener {
override fun onMove() {
Log.e(TAG, "onMove Called")
isScroll = isViewPagerScrollValid()
}
})
}
//Call this method from onPageSelected of viewpager
fun viewPageChanged() {
Log.e(TAG, "viewPageChanged called")
touchImageViewCustom = null
}
fun getCurrentParentView(): View? {
try {
Log.e(TAG, "getCurrentView called")
val currentItem = currentItem
for (i in 0 until childCount) {
val child = getChildAt(i)
val layoutParams = child.layoutParams as ViewPager.LayoutParams
val f = layoutParams.javaClass.getDeclaredField("position") //NoSuchFieldException
f.isAccessible = true
val position = f.get(layoutParams) as Int //IllegalAccessException
Log.e(TAG, "currentItem" + currentItem)
if (!layoutParams.isDecor && currentItem == position) {
Log.e(TAG, "getCurrentView" + child)
return child
}
}
} catch (e: NoSuchFieldException) {
Log.e(TAG, e.toString())
} catch (e: IllegalArgumentException) {
Log.e(TAG, e.toString())
} catch (e: IllegalAccessException) {
Log.e(TAG, e.toString())
}
return null
}
}
在 TouchImageView 类中，从 setImageBitmap、setImageDrawable 和 setImageURI 调用 getOriginalRectF()。
public RectF getOriginalRectF(){
Log.e(TAG,"getOriginalRectF called viewWidth"+viewWidth);
Log.e(TAG,"getOriginalRectF called viewHeight"+viewHeight);
if(originalRectF==null && viewHeight>0 && viewWidth>0){
if (mScaleType == ScaleType.FIT_XY) {
throw new UnsupportedOperationException("getZoomedRect() not supported with FIT_XY");
}
PointF topLeft = transformCoordTouchToBitmap(0, 0, true);
PointF bottomRight = transformCoordTouchToBitmap(viewWidth, viewHeight, true);
float w = getDrawableWidth(getDrawable());
float h = getDrawableHeight(getDrawable());
Log.e(TAG,"getOriginalRectF height"+h);
Log.e(TAG,"getOriginalRectF width"+w);
Log.e("getOriginalRectF","getZoomedRect topLeft"+topLeft.x +"-"+topLeft.y);
Log.e("getOriginalRectF","getZoomedRect bottomRight"+bottomRight.x +"-"+bottomRight.y);
originalRectF=new RectF(topLeft.x / w, topLeft.y / h, bottomRight.x / w, bottomRight.y / h);
}
return originalRectF;
}
【讨论】：
上述任何解决方案都不适合我。当我使用以下 ImageView 时，它对我有用：
import android.animation.ValueAnimator;
import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.Point;
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.View;
import android.view.ViewTreeObserver;
import android.view.animation.DecelerateInterpolator;
import android.widget.ImageView;
@SuppressLint("AppCompatCustomView")
public class TouchImageView extends ImageView implements ViewTreeObserver.OnGlobalLayoutListener,View.OnTouchListener {
private final static int SINGLE_TOUCH = 1; //Single point
private final static int DOUBLE_TOUCH = 2; //Double finger
//Multi-finger touch mode, single finger, double finger
private int mode;
//Distance between two finger touch points
private float oldDist;
private float newDist;
/**
* Maximum zoom level
*/
private static final float MAX_SCALE = 5f;
/**
* Double-click the zoom level
*/
private float mDoubleClickScale = 2;
/**
* Scales when initialization, if the picture is wide or higher than the screen, this value will be less than 0
*/
private float initScale = 1.0f;
private boolean once = true;
private RectF rectF;
/**
* Double-click detection
*/
private GestureDetector mGestureDetector;
private int x = 0;
private int y = 0;
private Point mPoint = new Point();
private final Matrix matrix = new Matrix();
private Matrix oldMatrix = new Matrix();
private ValueAnimator animator;
public TouchImageView(Context context) {
this(context, null);
}
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
super.setScaleType(ScaleType.MATRIX);
setOnTouchListener(this);
/**
* Double click to implement the picture to zoom
*/
mGestureDetector = new GestureDetector(context,
new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onDoubleTap(MotionEvent e) {
changeViewSize(e);
return true;
}
});
}
@Override
public boolean onTouch(View view, MotionEvent event) {
rectF = getMatrixRectF(); //Get image boundaries
if (mGestureDetector.onTouchEvent(event))
return true;
switch (event.getAction() & event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
//If the boundary of the picture is overstelled, then intercept the event, not letting ViewPager processing
if (rectF.width() > getWidth() || rectF.height() > getHeight()) {
getParent().requestDisallowInterceptTouchEvent(true);
}
mode = SINGLE_TOUCH;
x = (int) event.getRawX();
y = (int) event.getRawY();
break;
case MotionEvent.ACTION_MOVE:
if (mode >= DOUBLE_TOUCH) //Double finger zoom
{
getParent().requestDisallowInterceptTouchEvent(true);
newDist = calculateDist(event); //Calculate distance
Point point = getMiPoint(event); //Get the midpoint coordinates between the two-hand fingers
if (newDist > oldDist + 1) //Pixabay (add one to prevent jitter)
{
changeViewSize(oldDist, newDist, point); //Enlarge reduction according to distance
oldDist = newDist;
}
if (oldDist > newDist + 1) //Narrow
{
changeViewSize(oldDist, newDist, point);
oldDist = newDist;
}
}
if (mode == SINGLE_TOUCH) //Drag and drop
{
float dx = event.getRawX() - x;
float dy = event.getRawY() - y;
//If the boundary of the picture in the movement exceeds the screen, then intercept the event, do not let ViewPager processing
if (rectF.width() > getWidth() || rectF.height() > getHeight()) {
getParent().requestDisallowInterceptTouchEvent(true);
}
//If you move the picture to the right, don't intercept the event, let the ViewPager process
if (rectF.left >= 0 && dx > 0)
getParent().requestDisallowInterceptTouchEvent(false);
//If you move to the left, don't intercept the event, let ViewPager processing
if (rectF.right <= getWidth() && dx < 0)
getParent().requestDisallowInterceptTouchEvent(false);
if (getDrawable() != null) {
//If the image width or height does not exceed the screen, then it is forbidden to slide around or down.
if (rectF.width() <= getWidth())
dx = 0;
if (rectF.height() < getHeight())
dy = 0;
//If the picture moves down to the end, don't let it continue to move
if (rectF.top >= 0 && dy > 0)
dy = 0;
//If the picture moves up to the end, don't let it continue to move
if (rectF.bottom <= getHeight() && dy < 0)
dy = 0;
//When the movement distance is greater than 1, it moves because Action_Move is relatively sensitive.
// The finger can only detect the jitter of the finger and let the picture move.
if (Math.abs(dx) > 1 || Math.abs(dy) > 1)
matrix.postTranslate(dx, dy);
setImageMatrix(matrix);
}
}
x = (int) event.getRawX();
y = (int) event.getRawY();
break;
case MotionEvent.ACTION_POINTER_DOWN:
mode += 1;
oldDist = calculateDist(event);
Log.e("q", "" + "a");
Log.e(":::", "" + event.getPointerCount() + " " + event.getActionIndex() + " " + event.findPointerIndex(0));
break;
case MotionEvent.ACTION_POINTER_UP:
mode -= 1;
break;
case MotionEvent.ACTION_UP:
backToPosition();
mode = 0;
break;
//In Action_Move, the event is intercepted, sometimes Action_up can't trigger, so add Action_Cancel
case MotionEvent.ACTION_CANCEL:
backToPosition();
mode = 0;
break;
default:
break;
}
return true;
}
/**
* Calculate the distance between two finger touch points
*/
private float calculateDist(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float) Math.sqrt(x * x + y * y);
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
getViewTreeObserver().addOnGlobalLayoutListener(this);
}
/**
* If it is separated from the screen boundary, then the image boundary is combined with the screen boundary.
* If the finger moves quickly, the picture will have a blank distance after the picture is stopped, and then the judgment can no longer move,
* However, it has appeared before the next judgment can continue to move.
* So you need to reset
*/
private void backToPosition() {
if (rectF.left >= 0) { //Image Left boundary and screen from the screen
matrix.postTranslate(-rectF.left, 0);
setImageMatrix(matrix);
}
if (rectF.right <= getWidth()) { //Image Right Boundary and Screen Distance
matrix.postTranslate(getWidth() - rectF.right, 0);
setImageMatrix(matrix);
}
if (rectF.top >= 0) { //Image on the image and the screen from the screen
matrix.postTranslate(0, -rectF.top);
setImageMatrix(matrix);
}
if (rectF.bottom <= getHeight()) { //Image of the image and the screen
matrix.postTranslate(0, getHeight() - rectF.bottom);
setImageMatrix(matrix);
}
}
/**
* Get the zoom in the zoom of double finger zoom
*
* @return
*/
private Point getMiPoint(MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
mPoint.set((int) x / 2, (int) y / 2);
return mPoint;
}
/**
* Double finger zoom picture
*/
private void changeViewSize(float oldDist, float newDist, Point mPoint) {
float scale = newDist / oldDist; //scaling ratio
matrix.postScale(scale, scale, mPoint.x, mPoint.y);
checkBorderAndCenterWhenScale();
setImageMatrix(matrix);
//Prevent reduction is less than the initial picture size, need to reset
reSetMatrix();
//If the zoom has been larger than the target multiple, stop, because it is possible to be exceeded, then directly zoom to the target size
if (getMatrixValueX() >= MAX_SCALE)
{
matrix.postScale(MAX_SCALE/getMatrixValueX(), MAX_SCALE/getMatrixValueX(), x, y);
checkBorderAndCenterWhenScale();
setImageMatrix(matrix);
return;
}
}
/**
* Double click to zoom pictures
*/
private void changeViewSize(MotionEvent e) {
//Get double-click coordinates
final float x = e.getX();
final float y = e.getY();
//If you are still zooming, you will return directly.
if (animator != null && animator.isRunning())
return;
//Judgment is a state in which it is amplified or reduced
if (!isZoomChanged()) {
animator = ValueAnimator.ofFloat(1.0f, 2.0f);
} else {
animator = ValueAnimator.ofFloat(1.0f, 0.0f);
}
animator.setTarget(this);
animator.setDuration(500);
animator.setInterpolator(new DecelerateInterpolator());
animator.start();
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator valueAnimator) {
Float value = (Float) animator.getAnimatedValue();
matrix.postScale(value, value, x, y);
checkBorderAndCenterWhenScale();
setImageMatrix(matrix);
/**
* Control reduction range
* If it is already less than the initial size, then restore to the initial size, then stop
*/
if (checkRestScale()) {
matrix.set(oldMatrix);
setImageMatrix(matrix);
return;
}
/**
* Control the range of amplification
* If the magnification of the target is already larger than the target, it is directly in the target magnification.
* Then stop
*/
if (getMatrixValueX() >= mDoubleClickScale)
{
matrix.postScale(mDoubleClickScale/getMatrixValueX(), mDoubleClickScale/getMatrixValueX(), x, y);
checkBorderAndCenterWhenScale();
setImageMatrix(matrix);
return;
}
}
});
}
/**
* Judging whether the zoom level is changed
*
* @return TRUE expressed the non-initial value, FALSE indicates the initial value.
*/
private boolean isZoomChanged() {
float[] values = new float[9];
getImageMatrix().getValues(values);
//Get the current X-axis scale level
float scale = values[Matrix.MSCALE_X];
//Get the X-axis scaling level of the template, both
oldMatrix.getValues(values);
return scale != values[Matrix.MSCALE_X];
}
/**
* Reset Matrix
*/
private void reSetMatrix() {
if (checkRestScale()) {
matrix.set(oldMatrix);
setImageMatrix(matrix);
return;
}
}
/**
* Setup double-click a large multiple
*/
private void setDoubleClickScale(RectF rectF)
{
if(rectF.height()<getHeight()-100)
{
mDoubleClickScale=getHeight()/rectF.height();
}
else
mDoubleClickScale=2f;
}
/**
* Judging whether it needs to be reset
*
* @return When the current zoom level is less than the template zoom level, reset
*/
private boolean checkRestScale() {
// TODO Auto-generated method stub
float[] values = new float[9];
getImageMatrix().getValues(values);
//Get the current X-axis scale level
float scale = values[Matrix.MSCALE_X];
//Get the X-axis scaling level of the template, both
oldMatrix.getValues(values);
return scale < values[Matrix.MSCALE_X];
}
private float getMatrixValueX()
{
// TODO Auto-generated method stub
float[] values = new float[9];
getImageMatrix().getValues(values);
//Get the current X-axis scale level
float scale = values[Matrix.MSCALE_X];
//Get the X-axis scaling level of the template, both
oldMatrix.getValues(values);
return scale / values[Matrix.MSCALE_X];
}
/**
* When zooming, perform image display scope control
*/
private void checkBorderAndCenterWhenScale()
{
RectF rect = getMatrixRectF();
float deltaX = 0;
float deltaY = 0;
int width = getWidth();
int height = getHeight();
// Control range if wide or higher than the screen
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;
}
}
// If the width or higher is less than the screen, let it hit
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();
}
Log.e("TAG", "deltaX = " + deltaX + " , deltaY = " + deltaY);
matrix.postTranslate(deltaX, deltaY);
setImageMatrix(matrix);
}
/**
* Get the range of images according to the Matrix of the current picture
*
* @return
*/
private RectF getMatrixRectF()
{
RectF rect = new RectF();
Drawable d = getDrawable();
if (null != d)
{
rect.set(0, 0, d.getIntrinsicWidth(), d.getIntrinsicHeight());
matrix.mapRect(rect); //If this is not this, the output of the following Log will be the same as the previous sentence.
}
Log.e("aaaa",""+rect.bottom+" "+rect.left+" "+rect.right+" "+rect.top);
return rect;
}
@Override
public void onGlobalLayout() {
if (once)
{
Drawable d = getDrawable();
if (d == null)
return;
Log.e("TAG", d.getIntrinsicWidth() + " , " + d.getIntrinsicHeight());
int width = getWidth();
int height = getHeight();
// Get the width and high of the picture
int dw = d.getIntrinsicWidth();
int dh = d.getIntrinsicHeight();
float scale = 1.0f;
// If the image is wide or higher than the screen, zoom to the width or high of the screen.
if (dw > width && dh <= height)
{
scale = width * 1.0f / dw;
}
if (dh > height && dw <= width)
{
scale = height * 1.0f / dh;
}
// If the width and high are greater than the screen, it will make it adapt to the screen size according to the proportion.
if (dw > width && dh > height)
{
scale = Math.min(width * 1.0f / dw, height * 1.0f / dh);
}
initScale = scale;
Log.e("TAG", "initScale = " + initScale);
matrix.postTranslate((width - dw) / 2, (height - dh) / 2);
matrix.postScale(scale, scale, getWidth() / 2,
getHeight() / 2);
// Image Move to the screen center
setImageMatrix(matrix);
oldMatrix.set(getImageMatrix());
once = false;
RectF rectF=getMatrixRectF();
setDoubleClickScale(rectF);
}
}
}
另外，我使用了下面的 ExtendedViewPager：
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import androidx.viewpager.widget.ViewPager;
public class ExtendedViewPager extends ViewPager {
public ExtendedViewPager(Context context) {
super(context);
}
public ExtendedViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
try {
return super.onTouchEvent(ev);
} catch (IllegalArgumentException ex) {
ex.printStackTrace();
}
return false;
}
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
try {
return super.onInterceptTouchEvent(ev);
} catch (IllegalArgumentException ex) {
ex.printStackTrace();
}
return false;
}
}
【讨论】：