是否有一种通用的方法来显示大图，并使用户能够放大、缩小和平移图像?
到目前为止，我找到了两种方法:
覆盖ImageView，对于这样一个常见的问题，这似乎有点太多了。 使用webview，但对整体布局的控制较少等等。
当前回答
你可以尝试使用LayoutParams
public void zoom(boolean flag){
if(flag){
int width=40;
int height=40;
}
else{
int width=20;
int height=20;
}
RelativeLayout.LayoutParams param=new RelativeLayout.LayoutParams(width,height); //use the parent layout of the ImageView;
imageView.setLayoutParams(param); //imageView is the view which needs zooming.
}
ZoomIn = zoom(true); zoom = zoom(false);
其他回答
补充@Mike的回答。我还需要双击将图像恢复到第一次观看时的原始尺寸。所以我添加了一堆“orig…”实例变量，并添加了SimpleOnGestureListener。
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;
import android.widget.ImageView;
public class TouchImageView extends ImageView {
Matrix matrix = new Matrix();
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 3f;
float[] m;
float redundantXSpace, redundantYSpace, origRedundantXSpace, origRedundantYSpace;;
float width, height;
static final int CLICK = 3;
static final float SAVE_SCALE = 1f;
float saveScale = SAVE_SCALE;
float right, bottom, origWidth, origHeight, bmWidth, bmHeight, origScale, origBottom,origRight;
ScaleGestureDetector mScaleDetector;
GestureDetector mGestureDetector;
Context context;
public TouchImageView(Context context) {
super(context);
super.setClickable(true);
this.context = context;
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
matrix.setTranslate(1f, 1f);
m = new float[9];
setImageMatrix(matrix);
setScaleType(ScaleType.MATRIX);
setOnTouchListener(new OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
boolean onDoubleTapEvent = mGestureDetector.onTouchEvent(event);
if (onDoubleTapEvent) {
// Reset Image to original scale values
mode = NONE;
bottom = origBottom;
right = origRight;
last = new PointF();
start = new PointF();
m = new float[9];
saveScale = SAVE_SCALE;
matrix = new Matrix();
matrix.setScale(origScale, origScale);
matrix.postTranslate(origRedundantXSpace, origRedundantYSpace);
setImageMatrix(matrix);
invalidate();
return true;
}
mScaleDetector.onTouchEvent(event);
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
PointF curr = new PointF(event.getX(), event.getY());
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
last.set(event.getX(), event.getY());
start.set(last);
mode = DRAG;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
float deltaX = curr.x - last.x;
float deltaY = curr.y - last.y;
float scaleWidth = Math.round(origWidth * saveScale);
float scaleHeight = Math.round(origHeight * saveScale);
if (scaleWidth < width) {
deltaX = 0;
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
} else if (scaleHeight < height) {
deltaY = 0;
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
} else {
if (x + deltaX > 0)
deltaX = -x;
else if (x + deltaX < -right)
deltaX = -(x + right);
if (y + deltaY > 0)
deltaY = -y;
else if (y + deltaY < -bottom)
deltaY = -(y + bottom);
}
matrix.postTranslate(deltaX, deltaY);
last.set(curr.x, curr.y);
}
break;
case MotionEvent.ACTION_UP:
mode = NONE;
int xDiff = (int) Math.abs(curr.x - start.x);
int yDiff = (int) Math.abs(curr.y - start.y);
if (xDiff < CLICK && yDiff < CLICK)
performClick();
break;
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
}
setImageMatrix(matrix);
invalidate();
return true; // indicate event was handled
}
});
mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onDoubleTapEvent(MotionEvent e) {
return true;
}
});
}
@Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
bmWidth = bm.getWidth();
bmHeight = bm.getHeight();
}
public void setMaxZoom(float x) {
maxScale = x;
}
private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScaleBegin(ScaleGestureDetector detector) {
mode = ZOOM;
return true;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
float mScaleFactor = (float) Math.min(
Math.max(.95f, detector.getScaleFactor()), 1.05);
float origScale = saveScale;
saveScale *= mScaleFactor;
if (saveScale > maxScale) {
saveScale = maxScale;
mScaleFactor = maxScale / origScale;
} else if (saveScale < minScale) {
saveScale = minScale;
mScaleFactor = minScale / origScale;
}
right = width * saveScale - width
- (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
if (origWidth * saveScale <= width
|| origHeight * saveScale <= height) {
matrix.postScale(mScaleFactor, mScaleFactor, width / 2,
height / 2);
if (mScaleFactor < 1) {
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (Math.round(origWidth * saveScale) < width) {
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
} else {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
}
}
}
} else {
matrix.postScale(mScaleFactor, mScaleFactor,
detector.getFocusX(), detector.getFocusY());
matrix.getValues(m);
float x = m[Matrix.MTRANS_X];
float y = m[Matrix.MTRANS_Y];
if (mScaleFactor < 1) {
if (x < -right)
matrix.postTranslate(-(x + right), 0);
else if (x > 0)
matrix.postTranslate(-x, 0);
if (y < -bottom)
matrix.postTranslate(0, -(y + bottom));
else if (y > 0)
matrix.postTranslate(0, -y);
}
}
return true;
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
width = MeasureSpec.getSize(widthMeasureSpec);
height = MeasureSpec.getSize(heightMeasureSpec);
// Fit to screen.
float scale;
float scaleX = (float) width / (float) bmWidth;
float scaleY = (float) height / (float) bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = SAVE_SCALE;
origScale = scale;
// Center the image
redundantYSpace = (float) height - (scale * (float) bmHeight);
redundantXSpace = (float) width - (scale * (float) bmWidth);
redundantYSpace /= (float) 2;
redundantXSpace /= (float) 2;
origRedundantXSpace = redundantXSpace;
origRedundantYSpace = redundantYSpace;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height
- (2 * redundantYSpace * saveScale);
origRight = right;
origBottom = bottom;
setImageMatrix(matrix);
}
}
我刚刚整合了Robert Foss的TouchImageView:它完美地开箱即用!谢谢!
我只是修改了一些代码，所以我可以从我的layout.xml实例化它。
只需添加两个构造函数
public TouchImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public TouchImageView(Context context) {
super(context);
init(context);
}
并将旧的构造函数转换为init方法:
private void init(Context context){
//...old code ofconstructor of Robert Moss's code
}
In Response to Janusz original question, there are several ways to achieve this all of which vary in their difficulty level and have been stated below. Using a web view is good, but it is very limited in terms of look and feel and controllability. If you are drawing a bitmap from a canvas, the most versatile solutions that have been proposed seems to be MikeOrtiz's, Robert Foss's and/or what Jacob Nordfalk suggested. There is a great example for incorporating the android-multitouch-controller by PaulBourke, and is great for having the multi-touch support and alltypes of custom views.
就我个人而言，如果你只是简单地绘制一个画布到一个位图，然后在ImageView中显示它，并希望能够使用多点触摸缩放和移动，我发现MikeOrtiz的解决方案是最简单的。然而，出于我的目的，他提供的Git代码似乎只在他的TouchImageView自定义ImageView类是唯一的子类或提供布局参数时才能工作:
android:layout_height="match_parent"
android:layout_height="match_parent"
不幸的是，由于我的布局设计，我需要“wrap_content”为“layout_height”。当我把它改成这样的时候，图像在底部被裁剪了，我不能滚动或缩放到裁剪的区域。 所以我看了一下ImageView的源代码，看看Android是如何实现“onMeasure”的，并改变MikeOrtiz的以适应。
@Override
protected void onMeasure (int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
//**** ADDED THIS ********/////
int w = (int) bmWidth;
int h = (int) bmHeight;
width = resolveSize(w, widthMeasureSpec);
height = resolveSize(h, heightMeasureSpec);
//**** END ********///
// width = MeasureSpec.getSize(widthMeasureSpec); // REMOVED
// height = MeasureSpec.getSize(heightMeasureSpec); // REMOVED
//Fit to screen.
float scale;
float scaleX = (float)width / (float)bmWidth;
float scaleY = (float)height / (float)bmHeight;
scale = Math.min(scaleX, scaleY);
matrix.setScale(scale, scale);
setImageMatrix(matrix);
saveScale = 1f;
// Center the image
redundantYSpace = (float)height - (scale * (float)bmHeight) ;
redundantXSpace = (float)width - (scale * (float)bmWidth);
redundantYSpace /= (float)2;
redundantXSpace /= (float)2;
matrix.postTranslate(redundantXSpace, redundantYSpace);
origWidth = width - 2 * redundantXSpace;
origHeight = height - 2 * redundantYSpace;
// origHeight = bmHeight;
right = width * saveScale - width - (2 * redundantXSpace * saveScale);
bottom = height * saveScale - height - (2 * redundantYSpace * saveScale);
setImageMatrix(matrix);
}
这里的resolveSize(int,int)是一个实用程序，用于将所需的大小与MeasureSpec施加的约束进行协调，其中:
参数:
- size How big the view wants to be
- MeasureSpec Constraints imposed by the parent
返回:
- The size this view should be."
本质上提供了一种行为更类似于图像加载时的原始ImageView类。还可以进行更多的更改，以支持修改纵横比的各种屏幕。但现在我希望这能有所帮助。感谢MikeOrtiz的原始代码，做得很好。
This is a very late addition to this thread but I've been working on an image view that supports zoom and pan and has a couple of features I haven't found elsewhere. This started out as a way of displaying very large images without causing OutOfMemoryErrors, by subsampling the image when zoomed out and loading higher resolution tiles when zoomed in. It now supports use in a ViewPager, rotation manually or using EXIF information (90° stops), override of selected touch events using OnClickListener or your own GestureDetector or OnTouchListener, subclassing to add overlays, pan while zooming, and fling momentum.
它不打算作为ImageView的一般使用替代品，因此不扩展它，并且不支持显示来自资源的图像，只支持资产和外部文件。它需要SDK 10。
源代码在GitHub上，有一个示例说明了在ViewPager中的使用。
https://github.com/davemorrissey/subsampling-scale-image-view
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageDetail = (ImageView) findViewById(R.id.imageView1);
imageDetail.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
System.out.println("matrix=" + savedMatrix.toString());
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
startPoint.set(event.getX(), event.getY());
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(midPoint, event);
mode = ZOOM;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - startPoint.x, event.getY() - startPoint.y);
} else if (mode == ZOOM) {
float newDist = spacing(event);
if (newDist > 10f) {
matrix.set(savedMatrix);
float scale = newDist / oldDist;
matrix.postScale(scale, scale, midPoint.x, midPoint.y);
}
}
break;
}
view.setImageMatrix(matrix);
return true;
}
@SuppressLint("FloatMath")
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return FloatMath.sqrt(x * x + y * y);
}
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
});
}
和可绘制文件夹应该有bticn图像文件。 完美工作:)
推荐文章
- 如何允许所有网络连接类型HTTP和HTTPS在Android(9)馅饼?
- Android加载JS包失败
- Android Studio, logcat在应用程序关闭后清理
- 在android中从上下文获取活动
- 无法解析主机"<URL here>"没有与主机名关联的地址
- getActivity()在Fragment函数中返回null
- 按钮背景是透明的
- 在Mac OS X上哪里安装Android SDK ?
- 我如何获得图像缩放功能?
- 在Android应用程序中显示当前时间和日期
- BottomSheetDialogFragment的圆角
- 在应用程序启动时出现“无法获得BatchedBridge，请确保您的bundle被正确打包”的错误
- 我如何改变默认对话框按钮的文本颜色在安卓5
- 更改单选按钮的圆圈颜色
- 如何在android中复制一个文件?
