我关注guideline I found in the Android Developer Blog
但问题是它只在图像视图范围内移动和缩放。我想要的是用两个手指手势调整图像视图的大小。根据压力，它应该变得更大或更小。我一直在谷歌搜索整天调整大小，无法弄明白。所有教程只指向我在ImageView内部进行缩放而不是调整大小。 以下是我的自定义图像视图代码，来自博客。
public class InteractableImageView extends ImageView implements View.OnTouchListener {
private static final int INVALID_POINTER_ID = -1;
private ScaleGestureDetector mScaleDetector;
private float mScaleFactor = 1.f;
private int mActivePointerId = INVALID_POINTER_ID;
private float mPosX;
private float mPosY;
private float mLastTouchX;
private float mLastTouchY;
public InteractableImageView(Context context) {
this(context, null, 0);
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
}
public InteractableImageView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
}
public InteractableImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
}
public boolean onTouchEvent(MotionEvent ev) {
// Let the ScaleGestureDetector inspect all events.
mScaleDetector.onTouchEvent(ev);
final int action = ev.getAction();
switch (action & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: {
final float x = ev.getX();
final float y = ev.getY();
mLastTouchX = x;
mLastTouchY = y;
mActivePointerId = ev.getPointerId(0);
break;
}
case MotionEvent.ACTION_MOVE: {
final int pointerIndex = ev.findPointerIndex(mActivePointerId);
final float x = ev.getX(pointerIndex);
final float y = ev.getY(pointerIndex);
// Only move if the ScaleGestureDetector isn't processing a gesture.
if (!mScaleDetector.isInProgress()) {
final float dx = x - mLastTouchX;
final float dy = y - mLastTouchY;
mPosX += dx;
mPosY += dy;
invalidate();
}
mLastTouchX = x;
mLastTouchY = y;
break;
}
case MotionEvent.ACTION_UP: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_CANCEL: {
mActivePointerId = INVALID_POINTER_ID;
break;
}
case MotionEvent.ACTION_POINTER_UP: {
final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK)
>> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
final int pointerId = ev.getPointerId(pointerIndex);
if (pointerId == mActivePointerId) {
// This was our active pointer going up. Choose a new
// active pointer and adjust accordingly.
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mLastTouchX = ev.getX(newPointerIndex);
mLastTouchY = ev.getY(newPointerIndex);
mActivePointerId = ev.getPointerId(newPointerIndex);
}
break;
}
}
return true;
}
@Override public void onDraw(Canvas canvas) {
canvas.save();
canvas.translate(mPosX, mPosY);
canvas.scale(mScaleFactor, mScaleFactor);
super.onDraw(canvas);
canvas.restore();
}
@Override public boolean onTouch(View v, MotionEvent event) {
return false;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
@Override public boolean onScale(ScaleGestureDetector detector) {
mScaleFactor *= detector.getScaleFactor();
// Don't let the object get too small or too large.
mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 5.0f));
invalidate();
return true;
}
}
}
答案 0 :(得分：1)
试试这个。
在你的xml中，
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.yourpackagename.CustomImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="matrix"
android:src="@mipmap/ic_launcher"/>
</RelativeLayout>
CustomImageView，
import android.content.Context;
import android.graphics.Matrix;
import android.graphics.PointF;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ImageView;
/**
* Created by yeminhtut on 10/21/15.
*/
public class CustomImageView extends ImageView implements View.OnTouchListener {
Matrix matrix = new Matrix();
Matrix savedMatrix = new Matrix();
Matrix savedMatrix2 = 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;
float[] lastEvent;
float d;
// Remember some things for zooming
PointF start = new PointF();
PointF mid = new PointF();
float oldDist = 1f;
public CustomImageView(Context context) {
super(context);
}
public CustomImageView(Context context, AttributeSet attrs) {
super(context, attrs);
this.setOnTouchListener(this);
}
public CustomImageView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
public boolean onTouch(View v, MotionEvent event) {
ImageView view = (ImageView) v;
view.setScaleType(ImageView.ScaleType.MATRIX);
float scale;
// Handle touch events here...
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: //first finger down only
savedMatrix.set(matrix);
start.set(event.getX(), event.getY());
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if (oldDist > 10f) {
savedMatrix.set(matrix);
midPoint(mid, event);
mode = ZOOM;
}
lastEvent = new float[4];
lastEvent[0] = event.getX(0);
lastEvent[1] = event.getX(1);
lastEvent[2] = event.getY(0);
lastEvent[3] = event.getY(1);
d = rotation(event);
break;
case MotionEvent.ACTION_UP: //first finger lifted
case MotionEvent.ACTION_POINTER_UP: //second finger lifted
mode = NONE;
break;
case MotionEvent.ACTION_MOVE:
if (mode == DRAG) {
// ...
matrix.set(savedMatrix);
matrix.postTranslate(event.getX() - start.x, event.getY()
- start.y);
} else if (mode == ZOOM && event.getPointerCount() == 2) {
float newDist = spacing(event);
matrix.set(savedMatrix);
if (newDist > 10f) {
scale = newDist / oldDist;
matrix.postScale(scale, scale, mid.x, mid.y);
}
if (lastEvent != null) {
float newRot = rotation(event);
float r = newRot - d;
matrix.postRotate(r, view.getMeasuredWidth() / 2,
view.getMeasuredHeight() / 2);
}
}
break;
}
// Perform the transformation
fixing();
view.setImageMatrix(savedMatrix2);
return true; // indicate event was handled
}
public void fixing()
{
float[] value = new float[9];
matrix.getValues(value);
float[] savedValue = new float[9];
savedMatrix2.getValues(savedValue);
int width = this.getWidth();
int height = this.getHeight();
Drawable d = this.getDrawable();
if (d == null) return;
int imageWidth = d.getIntrinsicWidth();
int imageHeight = d.getIntrinsicHeight();
int scaleWidth = (int) (imageWidth * value[0]);
int scaleHeight = (int) (imageHeight * value[4]);
// don't let the image go outside
if (value[2] > width-1)
value[2] = width-10;
else if (value[5] > height - 1)
value[5] = height - 10;
else if (value[2] < -(scaleWidth-1))
value[2] = -(scaleWidth-10);
else if (value[5] < -(scaleHeight-1))
value[5] = -(scaleHeight-10);
matrix.setValues(value);
savedMatrix2.set(matrix);
}
private float rotation(MotionEvent event) {
double delta_x = (event.getX(0) - event.getX(1));
double delta_y = (event.getY(0) - event.getY(1));
double radians = Math.atan2(delta_y, delta_x);
return (float) Math.toDegrees(radians);
}
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float)Math.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);
}
}
希望这会有所帮助:)。 快乐的编码。
答案 1 :(得分：-1)