自定义可伸缩的imageView
直接上代码
/**
* 自定义可伸缩的ImageView
*/
public class ZoomImageView extends ImageView {
/** 画笔类 **/
private Paint mPaint;
private Runnable mRefresh = null;
/** 缩放手势监听类 **/
private ScaleGestureDetector mScaleDetector;
/** 手势识别类 **/
private GestureDetector mGestureDetector;
/** 当前被渲染的Bitmap **/
private Bitmap mBitmap;
private int mThisWidth = -1, mThisHeight = -1;
private Runnable mOnLayoutRunnable = null;
private Matrix mBaseMatrix = new Matrix();
private Matrix mDisplayMatrix = new Matrix();
private Matrix mSuppMatrix = new Matrix();
private Matrix mMatrix = new Matrix();
/** 最大的拉伸比例 **/
private float mMaxZoom;
private float[] mMatrixValues = new float[9];
private Runnable mFling = null;
private double mLastDraw = 0;
static final int sPaintDelay = 250;
public ZoomImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
public ZoomImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public ZoomImageView(Context context) {
super(context);
init();
}
@SuppressLint("NewApi")
private void init() {
mPaint = new Paint();
// 图像抖动处理
mPaint.setDither(true);
// 过滤优化操作 加快显示
mPaint.setFilterBitmap(true);
// 去掉锯齿
mPaint.setAntiAlias(true);
/** 刷新线程 **/
mRefresh = new Runnable() {
@Override
public void run() {
postInvalidate();
}
};
mScaleDetector = new ScaleGestureDetector(getContext(),
new ScaleListener());
mGestureDetector = new GestureDetector(getContext(),
new MyGestureListener());
// 判断是否是新的API 开启硬件加速
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
setLayerType(View.LAYER_TYPE_HARDWARE, null);
}
}
public Bitmap getImageBitmap() {
return mBitmap;
}
/** 回收Bitmap **/
public void clear() {
if (mBitmap != null && !mBitmap.isRecycled()) {
mBitmap.recycle();
mBitmap = null;
}
}
@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
mThisWidth = right - left;
mThisHeight = bottom - top;
Runnable r = mOnLayoutRunnable;
if (r != null) {
mOnLayoutRunnable = null;
r.run();
}
if (mBitmap != null) {
setBaseMatrix(mBitmap, mBaseMatrix);
setImageMatrix(getImageViewMatrix());
}
}
private void setBaseMatrix(Bitmap bitmap, Matrix matrix) {
float viewWidth = getWidth();
float viewHeight = getHeight();
matrix.reset();
float widthScale = Math
.min(viewWidth / (float) bitmap.getWidth(), 1.0f);
float heightScale = Math.min(viewHeight / (float) bitmap.getHeight(),
1.0f);
float scale;
if (widthScale > heightScale) {
scale = heightScale;
} else {
scale = widthScale;
}
/** 算取比例 进行平移 **/
matrix.setScale(scale, scale);
matrix.postTranslate(
(viewWidth - ((float) bitmap.getWidth() * scale)) / 2F,
(viewHeight - ((float) bitmap.getHeight() * scale)) / 2F);
}
public Matrix getImageViewMatrix() {
mDisplayMatrix.set(mBaseMatrix);
mDisplayMatrix.postConcat(mSuppMatrix);
return mDisplayMatrix;
}
public void setImageMatrix(Matrix m) {
/** Matrix是否为空并是否定义 **/
if (m != null && m.isIdentity()) {
m = null;
}
if (m == null && !this.mMatrix.isIdentity() || m != null
&& !this.mMatrix.equals(m)) {
this.mMatrix.set(m);
invalidate();
}
}
static private void translatePoint(Matrix matrix, float[] xy) {
matrix.mapPoints(xy);
}
/**
* 设置Bitmap
*
* @param bitmap
*/
@SuppressLint("NewApi")
public void setImageBitmap(final Bitmap bitmap) {
final int viewWidth = getWidth();
// 开启硬件加速
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB && bitmap != null && bitmap.getHeight() > 1800) {
setLayerType(View.LAYER_TYPE_SOFTWARE, null);
}
if (viewWidth <= 0) {
mOnLayoutRunnable = new Runnable() {
public void run() {
setImageBitmap(bitmap);
}
};
return;
}
if (bitmap != null) {
setBaseMatrix(bitmap, mBaseMatrix);
this.mBitmap = bitmap;
} else {
mBaseMatrix.reset();
this.mBitmap = bitmap;
}
mSuppMatrix.reset();
setImageMatrix(getImageViewMatrix());
mMaxZoom = maxZoom();
zoomTo(zoomDefault());
}
public void zoomTo(float scale) {
float width = getWidth();
float height = getHeight();
zoomTo(scale, width / 2F, height / 2F);
}
protected void zoomTo(float scale, float centerX, float centerY) {
if (scale > mMaxZoom) {
scale = mMaxZoom;
}
float oldScale = getScale();
float deltaScale = scale / oldScale;
/** 根据某个中心点按照比例缩放 **/
mSuppMatrix.postScale(deltaScale, deltaScale, centerX, centerY);
setImageMatrix(getImageViewMatrix());
center(true, true, false);
}
/**
* 计算中心位置
*
* @param vertical
* @param horizontal
* @param animate
*/
protected void center(boolean vertical, boolean horizontal, boolean animate) {
if (mBitmap == null)
return;
Matrix m = getImageViewMatrix();
float[] topLeft = new float[] { 0, 0 };
float[] botRight = new float[] { mBitmap.getWidth(),
mBitmap.getHeight() };
translatePoint(m, topLeft);
translatePoint(m, botRight);
float height = botRight[1] - topLeft[1];
float width = botRight[0] - topLeft[0];
float deltaX = 0, deltaY = 0;
if (vertical) {
int viewHeight = getHeight();
if (height < viewHeight) {
deltaY = (viewHeight - height) / 2 - topLeft[1];
} else if (topLeft[1] > 0) {
deltaY = -topLeft[1];
} else if (botRight[1] < viewHeight) {
deltaY = getHeight() - botRight[1];
}
}
if (horizontal) {
int viewWidth = getWidth();
if (width < viewWidth) {
deltaX = (viewWidth - width) / 2 - topLeft[0];
} else if (topLeft[0] > 0) {
deltaX = -topLeft[0];
} else if (botRight[0] < viewWidth) {
deltaX = viewWidth - botRight[0];
}
}
postTranslate(deltaX, deltaY);
if (animate) {
Animation a = new TranslateAnimation(-deltaX, 0, -deltaY, 0);
a.setStartTime(SystemClock.elapsedRealtime());
a.setDuration(250);
setAnimation(a);
}
setImageMatrix(getImageViewMatrix());
}
protected void postTranslate(float dx, float dy) {
mSuppMatrix.postTranslate(dx, dy);
}
public float getScale() {
return getScale(mSuppMatrix);
}
protected float getScale(Matrix matrix) {
if (mBitmap != null)
return getValue(matrix, Matrix.MSCALE_X);
else
return 1f;
}
protected float getValue(Matrix matrix, int whichValue) {
matrix.getValues(mMatrixValues);
return mMatrixValues[whichValue];
}
/**
* 计算最大的拉伸比例
*
* @return
*/
protected float maxZoom() {
if (mBitmap == null)
return 1F;
float fw = (float) mBitmap.getWidth() / (float) mThisWidth;
float fh = (float) mBitmap.getHeight() / (float) mThisHeight;
float max = Math.max(fw, fh) * 16;
return max;
}
/**
* 原始显示比例
*
* @return
*/
public float zoomDefault() {
if (mBitmap == null)
return 1F;
float fw = (float) mThisWidth / (float) mBitmap.getWidth();
float fh = (float) mThisHeight / (float) mBitmap.getHeight();
return Math.max(Math.min(fw, fh), 1);
}
protected void zoomTo(final float scale, final float centerX,
final float centerY, final float durationMs) {
final float incrementPerMs = (scale - getScale()) / durationMs;
final float oldScale = getScale();
final long startTime = System.currentTimeMillis();
post(new Runnable() {
public void run() {
long now = System.currentTimeMillis();
float currentMs = Math.min(durationMs,
(float) (now - startTime));
float target = oldScale + (incrementPerMs * currentMs);
zoomTo(target, centerX, centerY);
if (currentMs < durationMs) {
post(this);
}
}
});
}
protected void scrollBy(float distanceX, float distanceY,
final float durationMs) {
final float dx = distanceX;
final float dy = distanceY;
final long startTime = System.currentTimeMillis();
mFling = new Runnable() {
float old_x = 0;
float old_y = 0;
public void run() {
long now = System.currentTimeMillis();
float currentMs = Math.min(durationMs, now - startTime);
float x = easeOut(currentMs, 0, dx, durationMs);
float y = easeOut(currentMs, 0, dy, durationMs);
postTranslate((x - old_x), (y - old_y));
center(true, true, false);
old_x = x;
old_y = y;
if (currentMs < durationMs) {
post(this);
}
}
};
post(mFling);
}
private float easeOut(float time, float start, float end, float duration) {
return end * ((time = time / duration - 1) * time * time + 1) + start;
}
@SuppressLint("NewApi")
@Override
protected void onDraw(Canvas canvas) {
if (mBitmap != null && !mBitmap.isRecycled()) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB && getLayerType() == View.LAYER_TYPE_HARDWARE) {
canvas.drawBitmap(mBitmap, mMatrix, null);
} else {
if ((System.currentTimeMillis() - mLastDraw) > sPaintDelay) {
canvas.drawBitmap(mBitmap, mMatrix, mPaint);
mLastDraw = System.currentTimeMillis();
} else {
canvas.drawBitmap(mBitmap, mMatrix, null);
removeCallbacks(mRefresh);
postDelayed(mRefresh, sPaintDelay);
}
}
}
}
/**
* @author Administrator
*
* 手势缩放监听
*/
class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override
public boolean onScale(ScaleGestureDetector detector) {
if (detector != null && detector.isInProgress()) {
try {
float targetScale = getScale() * detector.getScaleFactor();
targetScale = Math.min(maxZoom(),
Math.max(targetScale, 1.0f));
zoomTo(targetScale, detector.getFocusX(),
detector.getFocusY());
invalidate();
return true;
} catch (IllegalArgumentException e) {
e.printStackTrace();
}
}
return false;
}
};
/**
* @author Administrator
*
* 手势识别监听
*/
class MyGestureListener extends GestureDetector.SimpleOnGestureListener {
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY) {
if ((e1 != null && e1.getPointerCount() > 1)
|| (e2 != null && e2.getPointerCount() > 1)
|| (mScaleDetector != null && mScaleDetector.isInProgress())) {
return false;
}
if (getScale() > zoomDefault()) {
removeCallbacks(mFling);
postTranslate(-distanceX, -distanceY);
center(true, true, false);
}
return true;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
float velocityY) {
if ((e1 != null && e1.getPointerCount() > 1) || (e2 != null && e2.getPointerCount() > 1)) {
return false;
}
if (mScaleDetector.isInProgress()) {
return false;
}
try {
float diffX = e2.getX() - e1.getX();
float diffY = e2.getY() - e1.getY();
if (Math.abs(velocityX) > 800 || Math.abs(velocityY) > 800) {
scrollBy(diffX / 2, diffY / 2, 300);
invalidate();
}
} catch (NullPointerException e) {
e.printStackTrace();
}
return super.onFling(e1, e2, velocityX, velocityY);
}
@Override
public boolean onDoubleTap(MotionEvent e) {
if (getScale() > zoomDefault()) {
zoomTo(zoomDefault());
} else
zoomTo(zoomDefault() * 3, e.getX(), e.getY(), 200);
return true;
}
@Override
public boolean onSingleTapConfirmed(MotionEvent e) {
// 设置点击事件
if (mImageTouchedListener != null) {
mImageTouchedListener.onImageTouched();
return false;
}
return super.onSingleTapConfirmed(e);
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (mBitmap != null) {
mScaleDetector.onTouchEvent(event);
if (!mScaleDetector.isInProgress()) {
mGestureDetector.onTouchEvent(event);
}
}
return true;
};
/**
*
* @author Administrator
*
* 点击接口
*/
private onImageTouchedListener mImageTouchedListener;
public interface onImageTouchedListener {
void onImageTouched();
}
public void setOnImageTouchedListener(onImageTouchedListener listener) {
this.mImageTouchedListener = listener;
}
}