如何在地图上方的透明ImageView上设置侦听器,仅对其上的捏合(缩放)事件做出反应,而移动地图等所有内容都由Google地图处理?
我的目标是在地图上创建中心缩放,可以这样做:
mGoogleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(mGoogleMap.getCameraPosition().target, amountOfZoomNeeded));
但是我需要首先捕获该pinch事件,并且只有onTouch使用下面的地图阻止该事件。
修改
我设法使用ScaleGestureDetectors onScale()方法创建了居中的缩放:
public class PinchListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
private GoogleMap googleMap;
public PinchListener(GoogleMap googleMap){
this.googleMap = googleMap;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
double zoom = googleMap.getCameraPosition().zoom;
zoom = zoom + Math.log(detector.getScaleFactor()) / Math.log(1.5d);
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(googleMap.getCameraPosition().target, (float) zoom);
googleMap.moveCamera(update);
return true;
}
}
在我的MainActivity中我初始化它,其中mMapWrapper是我前面提到的透明ImageView包装器。
ScaleGestureDetector mScaleGestureDetector = new ScaleGestureDetector(this, new PinchListener(mGoogleMap));
mMapWrapper.setOnTouchListener(new View.OnTouchListener(){
@Override
public boolean onTouch(View v, MotionEvent event) {
mScaleGestureDetector.onTouchEvent(event);
return true;
}
});
但是现在我遇到了一个我无法移动地图的问题,因为所有触摸事件都被包装器的onTouch()方法吃掉了。我该如何防止这种情况发生?
答案 0 :(得分:0)
所以这就是我设法做到这一点的方式。
我创建了两个用于检测某些事件的类,例如投掷,双击,滚动(拖动)和缩放(缩放):
public class PinchListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
private GoogleMap mGoogleMap;
public PinchListener(GoogleMap googleMap) {
this.mGoogleMap = googleMap;
}
@Override
public boolean onScale(ScaleGestureDetector detector) {
double zoom = mGoogleMap.getCameraPosition().zoom;
zoom = zoom + Math.log(detector.getScaleFactor()) / Math.log(1.5d);
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(mGoogleMap.getCameraPosition().target, (float) zoom);
mGoogleMap.moveCamera(update);
return true;
}
}
public class GestureListener extends GestureDetector.SimpleOnGestureListener {
private GoogleMap mGoogleMap;
private boolean mIsInAnimation;
public GestureListener(GoogleMap googleMap) {
this.mGoogleMap = googleMap;
mIsInAnimation = false;
}
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
LatLng target = mGoogleMap.getCameraPosition().target;
Point screenPoint = mGoogleMap.getProjection().toScreenLocation(target);
Point newPoint = new Point(screenPoint.x + (int) distanceX, screenPoint.y + (int) distanceY);
LatLng mapNewTarget = mGoogleMap.getProjection().fromScreenLocation(newPoint);
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(
mapNewTarget, mGoogleMap.getCameraPosition().zoom);
mGoogleMap.moveCamera(update);
return true;
}
@Override
public boolean onDoubleTap(MotionEvent e) {
mGoogleMap.animateCamera(CameraUpdateFactory.zoomIn(), 400, null);
return true;
}
@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
if (mIsInAnimation) return false;
int velocity = (int) Math.sqrt(velocityX * velocityX + velocityY * velocityY);
if (velocity < 500) return false;
double k1 = 0.002d; /*exipemental*/
double k2 = 0.002d;/*exipemental*/
LatLng target = mGoogleMap.getCameraPosition().target;
Point screenPoint = mGoogleMap.getProjection().toScreenLocation(target);
Point newPoint = new Point(screenPoint.x - (int) (velocityX * k1),
screenPoint.y - (int) (velocityY * k1));
LatLng mapNewTarget = mGoogleMap.getProjection().fromScreenLocation(newPoint);
CameraUpdate update = CameraUpdateFactory.newLatLngZoom(
mapNewTarget, mGoogleMap.getCameraPosition().zoom);
tryUpdateCamera(update, (int) (velocity * k2));
return true;
}
private void tryUpdateCamera(CameraUpdate update, int animateTime) {
mIsInAnimation = true;
mGoogleMap.animateCamera(update, animateTime, new GoogleMap.CancelableCallback() {
@Override
public void onFinish() {
mIsInAnimation = false;
}
@Override
public void onCancel() {
mIsInAnimation = false;
}
});
}
}
然后我在MainActivity中初始化了一个GestureDetector和ScaleGestureDetector:
ScaleGestureDetector mScaleGestureDetector = new ScaleGestureDetector(this, new PinchListener(mMap));
GestureDetector mGestureDetector = new GestureDetector(this, new GestureListener(mMap));
我已经在我的activity_main中创建了一个透明的图片包装器来检测所有这些事件,然后在下面的Google Map上模拟它们,如下所示:
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:id="@+id/map"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/mapWrapper"
/>
最后在我的MainActivity中,我为包装器创建了一个OnTouchListener:
mMapWrapper = findViewById(R.id.mapWrapper);
mMapWrapper.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
mMode = Mode.DRAG;
mGestureDetector.onTouchEvent(event);
mScaleGestureDetector.onTouchEvent(event);
break;
case MotionEvent.ACTION_POINTER_DOWN:
mMode = Mode.ZOOM;
mScaleGestureDetector.onTouchEvent(event);
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mMode = Mode.NONE;
mGestureDetector.onTouchEvent(event);
break;
case MotionEvent.ACTION_MOVE:
if (mMode == Mode.DRAG) {
mGestureDetector.onTouchEvent(event);
} else if (mMode == Mode.ZOOM) {
mScaleGestureDetector.onTouchEvent(event);
}
break;
}
return true;
}
});
在最后一步中,我向正确的探测器“提供”我想要的事件。如果我没有这样做,缩放将不会完全居中,因为有时会调用滚动(拖动)事件并且会移动地图。