import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.util.AttributeSet;
import android.util.FloatMath;
import android.view.MotionEvent;
import android.widget.ImageView;
public class ImageControl extends ImageView {
public ImageControl(Context context) {
super(context);
// TODO Auto-generated constructor stub
}
public ImageControl(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
public ImageControl(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}
// ImageView img;
Matrix imgMatrix = null; // 定义图片的变换矩阵
static final int DOUBLE_CLICK_TIME_SPACE = 300; // 双击时间间隔
static final int DOUBLE_POINT_DISTANCE = 10; // 两点放大两点间最小间距
static final int NONE = 0;
static final int DRAG = 1; // 拖动操作
static final int ZOOM = 2; // 放大缩小操作
private int mode = NONE; // 当前模式
float bigScale = 3f; // 默认放大倍数
Boolean isBig = false; // 是否是放大状态
long lastClickTime = 0; // 单击时间
float startDistance; // 多点触摸两点距离
float endDistance; // 多点触摸两点距离
float topHeight; // 状态栏高度和标题栏高度
Bitmap primaryBitmap = null;
float contentW; // 屏幕内容区宽度
float contentH; // 屏幕内容区高度
float primaryW; // 原图宽度
float primaryH; // 原图高度
float scale; // 适合屏幕缩放倍数
Boolean isMoveX = true; // 是否允许在X轴拖动
Boolean isMoveY = true; // 是否允许在Y轴拖动
float startX;
float startY;
float endX;
float endY;
float subX;
float subY;
float limitX1;
float limitX2;
float limitY1;
float limitY2;
ICustomMethod mCustomMethod = null;
/**
* 初始化图片
*
* @param bitmap
* 要显示的图片
* @param contentW
* 内容区域宽度
* @param contentH
* 内容区域高度
* @param topHeight
* 状态栏高度和标题栏高度之和
*/
public void imageInit(Bitmap bitmap, int contentW, int contentH,
int topHeight, ICustomMethod iCustomMethod) {

this.primaryBitmap = bitmap;
this.contentW = contentW;
this.contentH = contentH;
this.topHeight = topHeight;
mCustomMethod = iCustomMethod;
primaryW = primaryBitmap.getWidth();
primaryH = primaryBitmap.getHeight();
float scaleX = (float) contentW / primaryW;
float scaleY = (float) contentH / primaryH;
scale = scaleX < scaleY ? scaleX : scaleY;
if (scale < 1 && 1 / scale < bigScale) {
bigScale = (float) (1 / scale + 0.5);
}
imgMatrix = new Matrix();
subX = (contentW - primaryW * scale) / 2;
subY = (contentH - primaryH * scale) / 2;
this.setImageBitmap(primaryBitmap);
this.setScaleType(ScaleType.MATRIX);
imgMatrix.postScale(scale, scale);
imgMatrix.postTranslate(subX, subY);
this.setImageMatrix(imgMatrix);
}
/**
* 按下操作
*
* @param event
*/
public void mouseDown(MotionEvent event) {
mode = NONE;
startX = event.getRawX();
startY = event.getRawY();
if (event.getPointerCount() == 1) {
// 如果两次点击时间间隔小于一定值，则默认为双击事件
if (event.getEventTime() - lastClickTime < DOUBLE_CLICK_TIME_SPACE) {
changeSize(startX, startY);
} else if (isBig) {
mode = DRAG;
}
}
lastClickTime = event.getEventTime();
}
/**
* 非第一个点按下操作
*
* @param event
*/
public void mousePointDown(MotionEvent event) {
startDistance = getDistance(event);
if (startDistance > DOUBLE_POINT_DISTANCE) {
mode = ZOOM;
} else {
mode = NONE;
}
}
/**
* 移动操作
*
* @param event
*/
public void mouseMove(MotionEvent event) {
if ((mode == DRAG) && (isMoveX || isMoveY)) {
float[] XY = getTranslateXY(imgMatrix);
float transX = 0;
float transY = 0;
if (isMoveX) {
endX = event.getRawX();
transX = endX - startX;
if ((XY[0] + transX) <= limitX1) {
transX = limitX1 - XY[0];
}
if ((XY[0] + transX) >= limitX2) {
transX = limitX2 - XY[0];
}
}
if (isMoveY) {
endY = event.getRawY();
transY = endY - startY;
if ((XY[1] + transY) <= limitY1) {
transY = limitY1 - XY[1];
}
if ((XY[1] + transY) >= limitY2) {
transY = limitY2 - XY[1];
}
}
imgMatrix.postTranslate(transX, transY);
startX = endX;
startY = endY;
this.setImageMatrix(imgMatrix);
} else if (mode == ZOOM && event.getPointerCount() > 1) {
endDistance = getDistance(event);
float dif = endDistance - startDistance;
if (Math.abs(endDistance - startDistance) > DOUBLE_POINT_DISTANCE) {
if (isBig) {
if (dif < 0) {
changeSize(0, 0);
mode = NONE;
}
} else if (dif > 0) {
float x = event.getX(0) / 2 + event.getX(1) / 2;
float y = event.getY(0) / 2 + event.getY(1) / 2;
changeSize(x, y);
mode = NONE;
}
}
}
}
/**
* 鼠标抬起事件
*/
public void mouseUp() {
mode = NONE;
}
/**
* 图片放大缩小
*
* @param x

* 点击点X坐标
* @param y
* 点击点Y坐标
*/
private void changeSize(float x, float y) {
if (isBig) {
// 如果处于最大状态，则还原
imgMatrix.reset();
imgMatrix.postScale(scale, scale);
imgMatrix.postTranslate(subX, subY);
isBig = false;
} else {
imgMatrix.postScale(bigScale, bigScale); // 在原有矩阵后乘放大倍数
float transX = -((bigScale - 1) * x);
float transY = -((bigScale - 1) * (y - topHeight)); // (bigScale-1)(y-statusBarHeight-subY)+2*subY;
float currentWidth = primaryW * scale * bigScale; // 放大后图片大小
float currentHeight = primaryH * scale * bigScale;
// 如果图片放大后超出屏幕范围处理
if (currentHeight > contentH) {
limitY1 = -(currentHeight - contentH); // 平移限制
limitY2 = 0;
isMoveY = true; // 允许在Y轴上拖动
float currentSubY = bigScale * subY; // 当前平移距离
// 平移后，内容区域上部有空白处理办法
if (-transY < currentSubY) {
transY = -currentSubY;
}
// 平移后，内容区域下部有空白处理办法
if (currentSubY + transY < limitY1) {
transY = -(currentHeight + currentSubY - contentH);
}
} else {
// 如果图片放大后没有超出屏幕范围处理，则不允许拖动
isMoveY = false;
}
if (currentWidth > contentW) {
limitX1 = -(currentWidth - contentW);
limitX2 = 0;
isMoveX = true;
float currentSubX = bigScale * subX;
if (-transX < currentSubX) {
transX = -currentSubX;
}
if (currentSubX + transX < limitX1) {
transX = -(currentWidth + currentSubX - contentW);
}
} else {
isMoveX = false;
}
imgMatrix.postTranslate(transX, transY);
isBig = true;
}
this.setImageMatrix(imgMatrix);
if (mCustomMethod != null) {
mCustomMethod.customMethod(isBig);
}
}
/**
* 获取变换矩阵中X轴偏移量和Y轴偏移量
*
* @param matrix
* 变换矩阵
* @return
*/
private float[] getTranslateXY(Matrix matrix) {
float[] values = new float[9];
matrix.getValues(values);
float[] floats = new float[2];
floats[0] = values[Matrix.MTRANS_X];
floats[1] = values[Matrix.MTRANS_Y];
return floats;
}
/**
* 获取两点间的距离
*
* @param event
* @return
*/
private float getDistance(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);
}
/**
* @author Administrator 用户自定义方法
*/
public interface ICustomMethod {
public void customMethod(Boolean currentStatus);
}
}

ImageVewActivity.cs 这个用于测试的Activity

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Rect;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
import ejiang.boiler.ImageControl.ICustomMethod;
import ejiang.boiler.R.id;
public class ImageViewActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.common_image_view);
findView();
}
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
init();
}
ImageControl imgControl;
LinearLayout llTitle;
TextView tvTitle;
private void findView() {
imgControl = (ImageControl) findViewById(id.common_imageview_imageControl1);
llTitle = (LinearLayout) findViewById(id.common_imageview_llTitle);
tvTitle = (TextView) findViewById(id.common_imageview_title);
}
private void init() {
tvTitle.setText("图片测试");
// 这里可以为imgcontrol的图片路径动态赋值
// ............
Bitmap bmp;
if (imgControl.getDrawingCache() != null) {
bmp = Bitmap.createBitmap(imgControl.getDrawingCache());
} else {
bmp = ((BitmapDrawable) imgControl.getDrawable()).getBitmap();
}
Rect frame = new Rect();
getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);
int statusBarHeight = frame.top;
int screenW = this.getWindowManager().getDefaultDisplay().getWidth();
int screenH = this.getWindowManager().getDefaultDisplay().getHeight()
- statusBarHeight;
if (bmp != null) {
imgControl.imageInit(bmp, screenW, screenH, statusBarHeight,
new ICustomMethod() {
@Override
public void customMethod(Boolean currentStatus) {
// 当图片处于放大或缩小状态时，控制标题是否显示
if (currentStatus) {
llTitle.setVisibility(View.GONE);
} else {
llTitle.setVisibility(View.VISIBLE);
}
}
});
}
else
{
Toast.makeText(ImageViewActivity.this, "图片加载失败，请稍候再试！", Toast.LENGTH_SHORT)
.show();
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
imgControl.mouseDown(event);
break;
/**
* 非第一个点按下
*/
case MotionEvent.ACTION_POINTER_DOWN:
imgControl.mousePointDown(event);
break;
case MotionEvent.ACTION_MOVE:
imgControl.mouseMove(event);
break;
case MotionEvent.ACTION_UP:
imgControl.mouseUp();
break;
}
return super.onTouchEvent(event);
}
}
在上面的代码中，需要注意两点。一Activity中要重写onTouchEvent方法，将触摸事件传递到ImageControl，这点类似于WPF中的路由事件机制。二初始化imgControl即imgControl.imageInit，注意其中的参数。最后一个参数类似于C#中的委托，我这里使用接口来实现，在放大缩小的切换时要执行的操作都卸载这个方法中。

原文链接
http://blog.csdn.net/wuwo333/article/details/8057294