我正在浏览Tinder App的用户界面。我非常喜欢ImageView的Drag事件，我想实现相同的功能。我来了一点。但是当我缩放时，我找不到任何解决方案来刷新视图或增加视图的高度。
希望有人可以帮助我。
package com.scaleimageview;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.FloatMath;
import android.util.Log;
import android.view.DragEvent;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnDragListener;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
public class ScaleImageView extends ImageView implements OnTouchListener,
OnDragListener {
private Context mContext;
private float MAX_SCALE = 2f;
private Matrix mMatrix;
private final float[] mMatrixValues = new float[9];
// display width height.
private int mWidth;
private int mHeight;
private int mIntrinsicWidth;
private int mIntrinsicHeight;
private float mScale;
private float mMinScale;
private float mPrevDistance;
private boolean isScaling;
private int mPrevMoveX;
private int mPrevMoveY;
private GestureDetector mDetector;
String TAG = "ScaleImageView";
public ScaleImageView(Context context, AttributeSet attr) {
super(context, attr);
this.mContext = context;
initialize();
}
public ScaleImageView(Context context) {
super(context);
this.mContext = context;
initialize();
}
@Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
this.initialize();
}
@Override
public void setImageResource(int resId) {
super.setImageResource(resId);
this.initialize();
}
private void initialize() {
this.setScaleType(ScaleType.MATRIX);
this.mMatrix = new Matrix();
Drawable d = getDrawable();
if (d != null) {
mIntrinsicWidth = d.getIntrinsicWidth();
mIntrinsicHeight = d.getIntrinsicHeight();
setOnTouchListener(this);
setOnDragListener(this);
}
mDetector = new GestureDetector(mContext,
new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onDoubleTap(MotionEvent e) {
// maxZoomTo((int) e.getX(), (int) e.getY());
// cutting();
return super.onDoubleTap(e);
}
});
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Log.d("TAG", "called");
setMeasuredDimension(measureWidth(widthMeasureSpec),
measureHeight(heightMeasureSpec));
this.postInvalidate();
}
private int measureWidth(int measureSpec) {
Log.i("TAG WIDTH", measureSpec + "");
int preferred = this.getWidth() * 2;
return getMeasurement(measureSpec, preferred);
}
private int measureHeight(int measureSpec) {
Log.i("TAG HEIGHT", measureSpec + "");
int preferred = measureSpec * 2;
return getMeasurement(measureSpec, preferred);
}
private int getMeasurement(int measureSpec, int preferred) {
int specSize = MeasureSpec.getSize(measureSpec);
int measurement = 0;
switch (MeasureSpec.getMode(measureSpec)) {
case MeasureSpec.EXACTLY:
Log.d(TAG, "Exactly : " + specSize + "");
measurement = specSize;
break;
case MeasureSpec.AT_MOST:
Log.d(TAG, "At most : " + specSize + "");
// Take the minimum of the preferred size and what
// we were told to be.
measurement = Math.min(preferred, specSize);
break;
case MeasureSpec.UNSPECIFIED:
measurement = preferred;
Log.d("TAG UNSPECK", "This is called Prefered " + preferred
+ " This is for specSize : " + specSize);
default:
measurement = preferred;
break;
}
return measurement;
}
@Override
protected boolean setFrame(int l, int t, int r, int b) {
mWidth = r - l;
mHeight = b - t;
mMatrix.reset();
int r_norm = r - l;
mScale = (float) r_norm / (float) mIntrinsicWidth;
int paddingHeight = 0;
int paddingWidth = 0;
// scaling vertical
if (mScale * mIntrinsicHeight > mHeight) {
mScale = (float) mHeight / (float) mIntrinsicHeight;
mMatrix.postScale(mScale, mScale);
paddingWidth = (r - mWidth) / 2;
paddingHeight = 0;
// scaling horizontal
} else {
mMatrix.postScale(mScale, mScale);
paddingHeight = (b - mHeight) / 2;
paddingWidth = 0;
}
mMatrix.postTranslate(paddingWidth, paddingHeight);
setImageMatrix(mMatrix);
mMinScale = mScale;
zoomTo(mScale, mWidth / 2, mHeight / 2);
// this.onMeasure(480, 500);
cutting();
return super.setFrame(l, t, r, b);
}
protected float getValue(Matrix matrix, int whichValue) {
matrix.getValues(mMatrixValues);
return mMatrixValues[whichValue];
}
protected float getScale() {
return getValue(mMatrix, Matrix.MSCALE_X);
}
public float getTranslateX() {
return getValue(mMatrix, Matrix.MTRANS_X);
}
protected float getTranslateY() {
return getValue(mMatrix, Matrix.MTRANS_Y);
}
protected void maxZoomTo(int x, int y) {
if (mMinScale != getScale() && (getScale() - mMinScale) > 0.1f) {
// threshold 0.1f
float scale = mMinScale / getScale();
zoomTo(scale, x, y);
} else {
float scale = MAX_SCALE / getScale();
zoomTo(scale, x, y);
}
}
public void zoomTo(float scale, int x, int y) {
if (getScale() * scale < mMinScale) {
return;
}
if (scale >= 1 && getScale() * scale > MAX_SCALE) {
return;
}
mMatrix.postScale(scale, scale);
// move to center
mMatrix.postTranslate(-(mWidth * scale - mWidth) / 2,
-(mHeight * scale - mHeight) / 2);
// move x and y distance
mMatrix.postTranslate(-(x - (mWidth / 2)) * scale, 0);
mMatrix.postTranslate(0, -(y - (mHeight / 2)) * scale);
setImageMatrix(mMatrix);
}
public void cutting() {
int width = (int) (mIntrinsicWidth * getScale());
int height = (int) (mIntrinsicHeight * getScale());
if (getTranslateX() < -(width - mWidth)) {
mMatrix.postTranslate(-(getTranslateX() + width - mWidth), 0);
}
if (getTranslateX() > 0) {
mMatrix.postTranslate(-getTranslateX(), 0);
}
if (getTranslateY() < -(height - mHeight)) {
mMatrix.postTranslate(0, -(getTranslateY() + height - mHeight));
}
if (getTranslateY() > 0) {
mMatrix.postTranslate(0, -getTranslateY());
}
if (width < mWidth) {
mMatrix.postTranslate((mWidth - width) / 2, 0);
}
if (height < mHeight) {
mMatrix.postTranslate(0, (mHeight - height) / 2);
}
setImageMatrix(mMatrix);
}
private float distance(float x0, float y0) {
float x = x0;// - x1;
float y = y0; // - y1;
return FloatMath.sqrt(x * x + y * y);
}
private float dispDistance() {
return FloatMath.sqrt(mWidth * mWidth + mHeight * mHeight);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (mDetector.onTouchEvent(event)) {
return true;
}
int touchCount = event.getPointerCount();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_POINTER_INDEX_MASK:
if (touchCount == 1) {
Log.d("TAG", touchCount + "");
float distance = distance(event.getX(0), event.getY(0));
mPrevDistance = distance;
this.measure(480, 500);
isScaling = true;
} else {
mPrevMoveX = (int) event.getX();
mPrevMoveY = (int) event.getY();
}
break;
case MotionEvent.ACTION_POINTER_2_DOWN:
case MotionEvent.ACTION_MOVE:
if (touchCount == 1 && isScaling) {
float dist = distance(event.getX(0), event.getY(0));
float scale = (dist - mPrevDistance) / dispDistance();
this.measure(480, 500);
mPrevDistance = dist;
scale += 1;
scale = scale * scale;
zoomTo(scale, mWidth / 2, mHeight / 2);
cutting();
} else if (!isScaling) {
int distanceX = mPrevMoveX - (int) event.getX();
int distanceY = mPrevMoveY - (int) event.getY();
mPrevMoveX = (int) event.getX();
mPrevMoveY = (int) event.getY();
mMatrix.postTranslate(-distanceX, -distanceY);
cutting();
}
break;
case MotionEvent.ACTION_UP:
// if (isScaling) {
// isScaling = false;
// // handle single click
// } else if (ScaleImageView.this.isDragging()) {
// new Handler().postDelayed(new Runnable() {
// @Override
// public void run() {
// if (this.isDragging()) {
// // Drop never got received, so call stopDrag
// this.stopDrag();
// }
// }
// }, 1000);
// }
// break;
case MotionEvent.ACTION_POINTER_UP:
case MotionEvent.ACTION_POINTER_2_UP:
if (event.getPointerCount() <= 1) {
isScaling = false;
}
break;
}
return true;
}
@Override
public boolean onTouch(View v, MotionEvent event) {
int height = dpToPx(500);
Log.e("TAG", "" + height);
this.measure(this.getWidth(), height);
this.invalidate();
return super.onTouchEvent(event);
}
@Override
public boolean onDrag(View v, DragEvent event) {
int action = event.getAction();
switch (action) {
case DragEvent.ACTION_DRAG_STARTED:
break;
case DragEvent.ACTION_DRAG_EXITED:
// int ht = dpToPx(500);
// Log.e("TAG EXITED", "" + ht);
// this.measure(image.getWidth(), ht);
// Log.d("TAG", "Drag event exited from " + v.toString());
break;
}
return true;
}
public int dpToPx(int dp) {
DisplayMetrics displayMetrics = this.getResources().getDisplayMetrics();
int px = Math.round(dp
* (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
return px;
}
}
感谢任何帮助。
答案 0 :(得分：0)
public View.OnTouchListener listener（final float screen_width）{
View.OnTouchListener listener = new View.OnTouchListener() {
@Override
public boolean onTouch(View view, MotionEvent event) {
float oldx = screen_width/2 , fraction, min_alpha = 0.5f;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
oldx = event.getRawX();
break;
case MotionEvent.ACTION_MOVE:
//Get the distance of the touch from the initial touch point of the screen and divide it by half the screen width
fraction = ((event.getRawX() - oldx) / (screen_width/2) );
//set the view's rotation based on how far the user drags the image
view.setRotation(90 * fraction);
//set transparency of the view
view.setAlpha(1f - Math.abs(fraction) * ((1f - min_alpha)));
break;
case MotionEvent.ACTION_UP:
break;
}
return true;
}
};
return listener;
}
设置触摸侦听器说：imageView.setOnTouchListener（listener（screen_width）），以获取屏幕：
DisplayMetrics metrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(metrics);
screen_width = metrics.widthPixels;
*请注意，您可能需要更改imageView的轴心，以使旋转看起来接近于火种：
imageView.setPivotX(imageView.getWidth()/2);
imageView.setPivotY(imageView.getHeight());