我使用androidplot控件来显示某些值。如何保存缩放/平移状态？我必须使用哪些合适的属性？
plot_pan_zoom = PanZoom.attach(plot, PanZoom.Pan.BOTH, PanZoom.Zoom.STRETCH_BOTH, PanZoom.ZoomLimit.MIN_TICKS);
plot_pan_zoom.setDelegate(new View.OnTouchListener() {
private GestureDetector gestureDetector = new GestureDetector(MyActivity.this, new GestureDetector.SimpleOnGestureListener() {
@Override
public boolean onDoubleTap(MotionEvent e) {
// what properties to save/restore?
);
答案 0 :(得分：1)
没有专门为实现这一目标而构建的任何东西。
一种方法是创建自己的PanZoom变体来保存/恢复状态。以下是一个完整的实现，它添加了getState和setState方法，您可以在此处使用此方法：
@Override
public void onSaveInstanceState(Bundle bundle) {
bundle.putSerializable("todo", panZoom.getState());
}
@Override
public void onRestoreInstanceState(Bundle bundle) {
PanZoom.State state = (PanZoom.State) bundle.getSerializable("todo");
panZoom.setState(state);
plot.redraw();
}
修改后的PanZoom.java：
package com.androidplot.xy;
import android.graphics.RectF;
import android.graphics.PointF;
import android.support.annotation.NonNull;
import android.view.*;
import com.androidplot.*;
import com.androidplot.util.*;
import java.io.Serializable;
import java.util.*;
/**
* Enables basic pan/zoom touch behavior for an {@link XYPlot}.
* By default boundaries there are no boundaries imposed on scrolling and zooming. You can provide these boundaries
* on your {@link XYPlot} using {@link XYPlot#getOuterLimits()}.
* TODO: zoom using dynamic center point
* TODO: stretch both mode
*/
public class PanZoom implements View.OnTouchListener {
protected static final float MIN_DIST_2_FING = 5f;
protected static final int FIRST_FINGER = 0;
protected static final int SECOND_FINGER = 1;
private XYPlot plot;
private Pan pan;
private Zoom zoom;
private ZoomLimit zoomLimit;
private boolean isEnabled = true;
private DragState dragState = DragState.NONE;
private PointF firstFingerPos;
// rectangle created by the space between two fingers
protected RectF fingersRect;
private View.OnTouchListener delegate;
private State state = new State();
// Definition of the touch states
protected enum DragState {
NONE,
ONE_FINGER,
TWO_FINGERS
}
public enum Pan {
NONE,
HORIZONTAL,
VERTICAL,
BOTH
}
public enum Zoom {
/**
* Comletely disable panning
*/
NONE,
/**
* Zoom on the horizontal axis only
*/
STRETCH_HORIZONTAL,
/**
* Zoom on the vertical axis only
*/
STRETCH_VERTICAL,
/**
* Zoom on the vertical axis by the vertical distance between each finger, while zooming
* on the horizontal axis by the horizantal distance between each finger.
*/
STRETCH_BOTH,
/**
* Zoom each axis by the same amount, specifically the total distance between each finger.
*/
SCALE
}
/**
* Limits imposed on the zoom.
*/
public enum ZoomLimit {
/**
* Do not zoom outside the plots outer bounds, if they are defined.
*/
OUTER,
/**
* Additionally to the outer bounds if plot.StepModel defines a value based increment
* make sure at least one tick is visible by not zooming in further.
*/
MIN_TICKS
}
// TODO: consider making this immutable / threadsafe
public static class State implements Serializable {
private Number domainLowerBoundary;
private Number domainUpperBoundary;
private Number rangeLowerBoundary;
private Number rangeUpperBoundary;
private BoundaryMode domainBoundaryMode;
private BoundaryMode rangeBoundaryMode;
public void setDomainBoundaries(Number lowerBoundary, Number upperBoundary, BoundaryMode mode) {
this.domainLowerBoundary = lowerBoundary;
this.domainUpperBoundary = upperBoundary;
this.domainBoundaryMode = mode;
}
public void setRangeBoundaries(Number lowerBoundary, Number upperBoundary, BoundaryMode mode) {
this.rangeLowerBoundary = lowerBoundary;
this.rangeUpperBoundary = upperBoundary;
this.rangeBoundaryMode = mode;
}
public void applyDomainBoundaries(@NonNull XYPlot plot) {
plot.setDomainBoundaries(domainLowerBoundary, domainUpperBoundary, domainBoundaryMode);
}
public void applyRangeBoundaries(@NonNull XYPlot plot) {
plot.setRangeBoundaries(rangeLowerBoundary, rangeUpperBoundary, rangeBoundaryMode);
}
public void apply(@NonNull XYPlot plot) {
applyDomainBoundaries(plot);
applyRangeBoundaries(plot);
}
}
protected PanZoom(@NonNull XYPlot plot, Pan pan, Zoom zoom) {
this.plot = plot;
this.pan = pan;
this.zoom = zoom;
this.zoomLimit = ZoomLimit.OUTER;
}
// additional constructor not to break api
protected PanZoom(@NonNull XYPlot plot, Pan pan, Zoom zoom, ZoomLimit limit) {
this.plot = plot;
this.pan = pan;
this.zoom = zoom;
this.zoomLimit = limit;
}
public State getState() {
return this.state;
}
public void setState(@NonNull State state) {
this.state = state;
state.apply(plot);
}
protected void adjustRangeBoundary(Number lower, Number upper, BoundaryMode mode) {
state.setRangeBoundaries(lower, upper, mode);
state.applyRangeBoundaries(plot);
}
protected void adjustDomainBoundary(Number lower, Number upper, BoundaryMode mode) {
state.setDomainBoundaries(lower, upper, mode);
state.applyDomainBoundaries(plot);
}
/**
* Convenience method for enabling pan/zoom behavior on an instance of {@link XYPlot}, using
* a default behavior of {@link Pan#BOTH} and {@link Zoom#SCALE}.
* Use {@link PanZoom#attach(XYPlot, Pan, Zoom, ZoomLimit)} for finer grain control of this behavior.
* @param plot
* @return
*/
public static PanZoom attach(@NonNull XYPlot plot) {
return attach(plot, Pan.BOTH, Zoom.SCALE);
}
/**
* Old method for enabling pan/zoom behavior on an instance of {@link XYPlot}, using
* the default behavior of {@link ZoomLimit#OUTER}.
* Use {@link PanZoom#attach(XYPlot, Pan, Zoom, ZoomLimit)} for finer grain control of this behavior.
* @param plot
* @param pan
* @param zoom
* @return
*/
public static PanZoom attach(@NonNull XYPlot plot, @NonNull Pan pan, @NonNull Zoom zoom) {
return attach(plot,pan,zoom, ZoomLimit.OUTER);
}
/**
* New method for enabling pan/zoom behavior on an instance of {@link XYPlot}.
* @param plot
* @param pan
* @param zoom
* @param limit
* @return
*/
public static PanZoom attach(@NonNull XYPlot plot, @NonNull Pan pan, @NonNull Zoom zoom, @NonNull ZoomLimit limit) {
PanZoom pz = new PanZoom(plot, pan, zoom, limit);
plot.setOnTouchListener(pz);
return pz;
}
public boolean isEnabled() {
return isEnabled;
}
public void setEnabled(boolean enabled) {
isEnabled = enabled;
}
@Override
public boolean onTouch(final View view, final MotionEvent event) {
boolean isConsumed = false;
if (delegate != null) {
isConsumed = delegate.onTouch(view, event);
}
if (isEnabled() && !isConsumed) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN: // start gesture
firstFingerPos = new PointF(event.getX(), event.getY());
dragState = DragState.ONE_FINGER;
break;
case MotionEvent.ACTION_POINTER_DOWN: // second finger
{
setFingersRect(fingerDistance(event));
// the distance run is done to avoid false alarms
if (getFingersRect().width() > MIN_DIST_2_FING || getFingersRect().width() < -MIN_DIST_2_FING) {
dragState = DragState.TWO_FINGERS;
}
break;
}
case MotionEvent.ACTION_POINTER_UP: // end zoom
dragState = DragState.NONE;
break;
case MotionEvent.ACTION_MOVE:
if (dragState == DragState.ONE_FINGER) {
pan(event);
} else if (dragState == DragState.TWO_FINGERS) {
zoom(event);
}
break;
case MotionEvent.ACTION_UP:
reset();
break;
}
}
// we're forced to consume the event here as not consuming it will prevent future calls:
return true;
}
/**
* Calculates the distance between two finger motion events.
* @param firstFingerX
* @param firstFingerY
* @param secondFingerX
* @param secondFingerY
* @return
*/
protected RectF fingerDistance(float firstFingerX, float firstFingerY, float secondFingerX, float secondFingerY) {
final float left = firstFingerX > secondFingerX ? secondFingerX : firstFingerX;
final float right = firstFingerX > secondFingerX ? firstFingerX : secondFingerX;
final float top = firstFingerY > secondFingerY ? secondFingerY : firstFingerY;
final float bottom = firstFingerY > secondFingerY ? firstFingerY : secondFingerY;
return new RectF(left, top, right, bottom);
}
/**
* Calculates the distance between two finger motion events.
* @param evt
* @return
*/
protected RectF fingerDistance(final MotionEvent evt) {
return fingerDistance(
evt.getX(FIRST_FINGER),
evt.getY(FIRST_FINGER),
evt.getX(SECOND_FINGER),
evt.getY(SECOND_FINGER));
}
protected void pan(final MotionEvent motionEvent) {
if (pan == Pan.NONE) {
return;
}
final PointF oldFirstFinger = firstFingerPos; //save old position of finger
firstFingerPos = new PointF(motionEvent.getX(), motionEvent.getY()); //update finger position
if (EnumSet.of(Pan.HORIZONTAL, Pan.BOTH).contains(pan)) {
Region newBounds = new Region();
calculatePan(oldFirstFinger, newBounds, true);
adjustDomainBoundary(newBounds.getMin(), newBounds.getMax(), BoundaryMode.FIXED);
}
if (EnumSet.of(Pan.VERTICAL, Pan.BOTH).contains(pan)) {
Region newBounds = new Region();
calculatePan(oldFirstFinger, newBounds, false);
adjustRangeBoundary(newBounds.getMin(), newBounds.getMax(), BoundaryMode.FIXED);
}
plot.redraw();
}
protected void calculatePan(final PointF oldFirstFinger, Region bounds, final boolean horizontal) {
final float offset;
// multiply the absolute finger movement for a factor.
// the factor is dependent on the calculated min and max
if (horizontal) {
bounds.setMinMax(plot.getBounds().getxRegion());
offset = (oldFirstFinger.x - firstFingerPos.x) *
((bounds.getMax().floatValue() - bounds.getMin().floatValue()) / plot.getWidth());
} else {
bounds.setMinMax(plot.getBounds().getyRegion());
offset = -(oldFirstFinger.y - firstFingerPos.y) *
((bounds.getMax().floatValue() - bounds.getMin().floatValue()) / plot.getHeight());
}
// move the calculated offset
bounds.setMin(bounds.getMin().floatValue() + offset);
bounds.setMax(bounds.getMax().floatValue() + offset);
//get the distance between max and min
final float diff = bounds.length().floatValue();
//run if we reached the limit of panning
if (horizontal && plot.getOuterLimits().getxRegion().isDefined()) {
if (bounds.getMin().floatValue() < plot.getOuterLimits().getMinX().floatValue()) {
bounds.setMin(plot.getOuterLimits().getMinX());
bounds.setMax(bounds.getMin().floatValue() + diff);
}
if (bounds.getMax().floatValue() > plot.getOuterLimits().getMaxX().floatValue()) {
bounds.setMax(plot.getOuterLimits().getMaxX());
bounds.setMin(bounds.getMax().floatValue() - diff);
}
} else if(plot.getOuterLimits().getyRegion().isDefined()) {
if (bounds.getMin().floatValue() < plot.getOuterLimits().getMinY().floatValue()) {
bounds.setMin(plot.getOuterLimits().getMinY());
bounds.setMax(bounds.getMin().floatValue() + diff);
}
if (bounds.getMax().floatValue() > plot.getOuterLimits().getMaxY().floatValue()) {
bounds.setMax(plot.getOuterLimits().getMaxY());
bounds.setMin(bounds.getMax().floatValue() - diff);
}
}
}
protected boolean isValidScale(float scale) {
return !Float.isInfinite(scale) && !Float.isNaN(scale) && (!(scale > -0.001) || !(scale < 0.001));
}
protected void zoom(final MotionEvent motionEvent) {
if (zoom == Zoom.NONE) {
return;
}
final RectF oldFingersRect = getFingersRect();
final RectF newFingersRect = fingerDistance(motionEvent);
setFingersRect(newFingersRect);
if(oldFingersRect == null || RectFUtils.areIdentical(oldFingersRect, newFingersRect)) {
// zooming gesture has not happened yet so skip:
return;
}
RectF newRect = new RectF();
float scaleX = 1;
float scaleY = 1;
switch (zoom) {
case STRETCH_HORIZONTAL:
scaleX = oldFingersRect.width() / getFingersRect().width();
if (!isValidScale(scaleX)) {
return;
}
break;
case STRETCH_VERTICAL:
scaleY = oldFingersRect.height() / getFingersRect().height();
if (!isValidScale(scaleY)) {
return;
}
break;
case STRETCH_BOTH:
scaleX = oldFingersRect.width() / getFingersRect().width();
scaleY = oldFingersRect.height() / getFingersRect().height();
if (!isValidScale(scaleX) || !isValidScale(scaleY)) {
return;
}
break;
case SCALE:
float sc1 = (float) Math.hypot(oldFingersRect.height(), oldFingersRect.width());
float sc2 = (float) Math.hypot(getFingersRect().height(), getFingersRect().width());
float sc = sc1 / sc2;
scaleX = sc;
scaleY = sc;
if (!isValidScale(scaleX) || !isValidScale(scaleY)) {
return;
}
break;
}
if (EnumSet.of(
Zoom.STRETCH_HORIZONTAL,
Zoom.STRETCH_BOTH,
Zoom.SCALE).contains(zoom)) {
calculateZoom(newRect, scaleX, true);
adjustDomainBoundary(newRect.left, newRect.right, BoundaryMode.FIXED);
}
if (EnumSet.of(
Zoom.STRETCH_VERTICAL,
Zoom.STRETCH_BOTH,
Zoom.SCALE).contains(zoom)) {
calculateZoom(newRect, scaleY, false);
adjustRangeBoundary(newRect.top, newRect.bottom, BoundaryMode.FIXED);
}
plot.redraw();
}
/**
*
* @param newRect RectF into which zoom calculation results should be placed.
* @param scale
* @param isHorizontal
*/
protected void calculateZoom(RectF newRect, float scale, boolean isHorizontal) {
final float calcMax;
final float span;
final RectRegion bounds = plot.getBounds();
if (isHorizontal) {
calcMax = bounds.getMaxX().floatValue();
span = calcMax - bounds.getMinX().floatValue();
} else {
calcMax = bounds.getMaxY().floatValue();
span = calcMax - bounds.getMinY().floatValue();
}
final float midPoint = calcMax - (span / 2.0f);
float offset = span * scale / 2.0f;
final RectRegion limits = plot.getOuterLimits();
if (isHorizontal ) {
// zoom limited and increment by value StepMode?
if (zoomLimit == ZoomLimit.MIN_TICKS) {
// make sure we do not zoom in too far (there should be at least one grid line visible)
if (plot.getDomainStepValue() > (scale*span)) {
offset = (float)(plot.getDomainStepValue() / 2.0f);
}
}
newRect.left = midPoint - offset;
newRect.right = midPoint + offset;
if(limits.isFullyDefined()) {
if (newRect.left < limits.getMinX().floatValue()) {
newRect.left = limits.getMinX().floatValue();
}
if (newRect.right > limits.getMaxX().floatValue()) {
newRect.right = limits.getMaxX().floatValue();
}
}
} else {
// zoom limited and increment by value StepMode?
if (zoomLimit == ZoomLimit.MIN_TICKS) {
// make sure we do not zoom in too far (there should be at least one grid line visible)
if (plot.getRangeStepValue() > (scale*span)) {
offset = (float)(plot.getRangeStepValue() / 2.0f);
}
}
newRect.top = midPoint - offset;
newRect.bottom = midPoint + offset;
if(limits.isFullyDefined()) {
if (newRect.top < limits.getMinY().floatValue()) {
newRect.top = limits.getMinY().floatValue();
}
if (newRect.bottom > limits.getMaxY().floatValue()) {
newRect.bottom = limits.getMaxY().floatValue();
}
}
}
}
public Pan getPan() {
return pan;
}
public void setPan(Pan pan) {
this.pan = pan;
}
public Zoom getZoom() {
return zoom;
}
public void setZoom(Zoom zoom) {
this.zoom = zoom;
}
public ZoomLimit getZoomLimit() {
return zoomLimit;
}
public void setZoomLimit(ZoomLimit zoomLimit) {
this.zoomLimit = zoomLimit;
}
public View.OnTouchListener getDelegate() {
return delegate;
}
/**
* Set a delegate to receive onTouch calls before this class does. If the delegate wishes
* to consume the event, it should return true, otherwise it should return false. Returning
* false will not prevent future onTouch events from filtering through the delegate as it normally
* would when attaching directly to an instance of {@link View}.
* @param delegate
*/
public void setDelegate(View.OnTouchListener delegate) {
this.delegate = delegate;
}
public void reset() {
this.firstFingerPos = null;
setFingersRect(null);
this.setFingersRect(null);
}
protected RectF getFingersRect() {
return fingersRect;
}
protected void setFingersRect(RectF fingersRect) {
this.fingersRect = fingersRect;
}
}
或者你可以创建一个扩展XYPlot的包装类，并覆盖setRangeBoundaries和setDomainBoundaries来缓存PanZoom对这些方法的调用。然后，您只需分别重复对每个方法的最近调用，以恢复平移/缩放状态。