package whu.iss.activity;
import java.util.Observable;
import java.util.Observer;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;
public class ImageZoomView extends View implements Observer {
private final Paint mPaint = new Paint(Paint.FILTER_BITMAP_FLAG);
private final Rect mRectSrc = new Rect();
private final Rect mRectDst = new Rect();
private float mAspectQuotient;
private Bitmap mBitmap;
private ZoomState mState;
public ImageZoomView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public void setZoomState(ZoomState state) {
if (mState != null) {
mState.deleteObserver(this);
}
mState = state;
mState.addObserver(this);
invalidate();
}
protected void onDraw(Canvas canvas) {
if (mBitmap != null && mState != null) {
final int viewWidth = getWidth();
final int viewHeight = getHeight();
final int bitmapWidth = mBitmap.getWidth();
final int bitmapHeight = mBitmap.getHeight();
final float panX = mState.getPanX();
final float panY = mState.getPanY();
final float zoomX = mState.getZoomX(mAspectQuotient) * viewWidth / bitmapWidth;
final float zoomY = mState.getZoomY(mAspectQuotient) * viewHeight / bitmapHeight;
// Setup source and destination rectangles
mRectSrc.left = (int)(panX * bitmapWidth - viewWidth / (zoomX * 2));
mRectSrc.top = (int)(panY * bitmapHeight - viewHeight / (zoomY * 2));
mRectSrc.right = (int)(mRectSrc.left + viewWidth / zoomX);
mRectSrc.bottom = (int)(mRectSrc.top + viewHeight / zoomY);
mRectDst.left = getLeft();
mRectDst.top = getTop();
mRectDst.right = getRight();
mRectDst.bottom = getBottom();
// Adjust source rectangle so that it fits within the source image.
if (mRectSrc.left < 0) {
mRectDst.left += -mRectSrc.left * zoomX;
mRectSrc.left = 0;
}
if (mRectSrc.right > bitmapWidth) {
mRectDst.right -= (mRectSrc.right - bitmapWidth) * zoomX;
mRectSrc.right = bitmapWidth;
}
if (mRectSrc.top < 0) {
mRectDst.top += -mRectSrc.top * zoomY;
mRectSrc.top = 0;
}
if (mRectSrc.bottom > bitmapHeight) {
mRectDst.bottom -= (mRectSrc.bottom - bitmapHeight) * zoomY;
mRectSrc.bottom = bitmapHeight;
}
canvas.drawBitmap(mBitmap, mRectSrc, mRectDst, mPaint);
}
}
public void update(Observable observable, Object data) {
invalidate();
}
private void calculateAspectQuotient() {
if (mBitmap != null) {
mAspectQuotient =
(((float)mBitmap.getWidth()) / mBitmap.getHeight()) /
(((float)getWidth()) / getHeight());
}
}
public void setImage(Bitmap bitmap) {
mBitmap = bitmap;
calculateAspectQuotient();
invalidate();
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
calculateAspectQuotient();
}
}
控件以及双指放大缩小图片、单指拖动图片.zip （35个子文件） 
控件以及双指放大缩小图片、单指拖动图片 控件以及双指放大缩小图片、单指拖动图片 
ZoomPage.rar 2.1MB ZoomPage ZoomPage bin 
classes.dex 12KB ZoomPage.apk 1.37MB whu iss activity main.class 3KB main$2.class 1024B R$layout.class 398B SimpleZoomListener.class 3KB ZoomState.class 1KB R$id.class 481B R$drawable.class 395B R$attr.class 334B R.class 517B R$string.class 421B main$1.class 2KB SimpleZoomListener$ControlType.class 1KB ImageZoomView.class 3KB main$3.class 971B main$4.class 971B resources.ap_ 1.36MB res drawable-ldpi 
earth.png 354KB drawable-hdpi earth.png 354KB drawable-xhdpi earth.png 354KB values strings.xml 161B drawable-mdpi earth.png 354KB layout activity_image.xml 2KB assets default.properties 362B gen whu iss activity R.java 913B proguard.cfg 1KB src whu iss activity main.java 2KB SimpleZoomListener.java 3KB ZoomState.java 1KB ImageZoomView.java 4KB .project 844B .classpath 280B AndroidManifest.xml 634B资源评论
