问题
I'm trying to draw a resizable circle on google map, which the user will be able to expand or shrink using touch gestures and also want it to work like zooming in/out option in the map, only that just the circle will get bigger/smaller on the map.
I can draw a circle on the map but i don't know how to get it to respond to touch events.
Here is my code
MainActivity.java
public class MainActivity extends FragmentActivity implements LocationListener {
GoogleMap googleMap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Getting Google Play availability status
int status = GooglePlayServicesUtil
.isGooglePlayServicesAvailable(getBaseContext());
// Showing status
if (status != ConnectionResult.SUCCESS) { // Google Play Services are
// not available
int requestCode = 10;
Dialog dialog = GooglePlayServicesUtil.getErrorDialog(status, this,
requestCode);
dialog.show();
} else { // Google Play Services are available
// Getting reference to the SupportMapFragment of activity_main.xml
SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
// Getting GoogleMap object from the fragment
googleMap = fm.getMap();
// Enabling MyLocation Layer of Google Map
googleMap.setMyLocationEnabled(true);
// Getting LocationManager object from System Service
// LOCATION_SERVICE
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
// Creating a criteria object to retrieve provider
Criteria criteria = new Criteria();
// Getting the name of the best provider
String provider = locationManager.getBestProvider(criteria, true);
// Getting Current Location
Location location = locationManager.getLastKnownLocation(provider);
if (location != null) {
onLocationChanged(location);
}
locationManager.requestLocationUpdates(provider, 20000, 0, this);
}
}
@Override
public void onLocationChanged(Location location) {
// TextView tvLocation = (TextView) findViewById(R.id.tv_location);
// Getting latitude of the current location
double latitude = location.getLatitude();
// Getting longitude of the current location
double longitude = location.getLongitude();
// Creating a LatLng object for the current location
LatLng latLng = new LatLng(latitude, longitude);
// Showing the current location in Google Map
googleMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
// Zoom in the Google Map
googleMap.animateCamera(CameraUpdateFactory.zoomTo(15));
// Setting latitude and longitude in the TextView tv_location
// tvLocation.setText("Latitude:" + latitude + ", Longitude:"+ longitude
// );
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
Main.xml
<RelativeLayout 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"
tools:context=".MainActivity" >
<fragment
android:id="@+id/map"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="com.google.android.gms.maps.SupportMapFragment"
/>
<in.locationingooglemapv2.CircleTouchView
android:id="@+id/circle_drawer_view"
android:layout_width="match_parent"
android:layout_height="match_parent" android:focusable="false"/>
</RelativeLayout>
CircleTouchView.java
package in.locationingooglemapv2;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
public class CircleTouchView extends View {
private static final String TAG = "CircleView";
private static final double MOVE_SENSITIVITY = 1.25;
private Paint circlePaint;
private boolean isPinchMode;
private int lastCircleX;
private int lastCircleY;
public Circle circle;
private boolean isDoneResizing = true;
public CircleTouchView(Context context) {
super(context);
setCirclePaint(0x220000ff);
}
public CircleTouchView(Context context, AttributeSet attrs) {
super(context, attrs);
setCirclePaint(0x220000ff);
}
public CircleTouchView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
setCirclePaint(0x220000ff);
}
private void setCirclePaint(int color) {
circle = new Circle();
circlePaint = new Paint();
circlePaint.setColor(color);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawCircle(circle.centerX, circle.centerY, circle.radius, circlePaint);
}
@Override
public boolean onTouchEvent(final MotionEvent event) {
int historySize;
double lastDistance;
double oneBeforeLastDistance;
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
lastCircleX = circle.centerX;
lastCircleY = circle.centerY;
break;
case MotionEvent.ACTION_POINTER_DOWN:
isPinchMode = true;
isDoneResizing = false;
break;
case MotionEvent.ACTION_MOVE:
circle.centerX = lastCircleX;
circle.centerY = lastCircleY;;
if (getTouchedCircle((int) event.getX(), (int) event.getY()) && !isPinchMode && isDoneResizing) {
historySize = event.getHistorySize();
if (historySize > 0) {
oneBeforeLastDistance = Math.sqrt((event.getX() - event.getHistoricalX(0, historySize - 1)) *
(event.getX() - event.getHistoricalX(0, historySize - 1)) +
(event.getY() - event.getHistoricalY(0, historySize - 1)) *
(event.getY() - event.getHistoricalY(0, historySize - 1)));
if (oneBeforeLastDistance > MOVE_SENSITIVITY) {
circle.centerX = (int) event.getX();
circle.centerY = (int) event.getY();
lastCircleX = circle.centerX;
lastCircleY = circle.centerY;
}
}
}
if (isPinchMode) {
circle.centerX = lastCircleX;
circle.centerY = lastCircleY;
historySize = event.getHistorySize();
if (historySize > 0) {
lastDistance = Math.sqrt((event.getX(0) - event.getX(1)) * (event.getX(0) - event.getX(1)) +
(event.getY(0) - event.getY(1)) * (event.getY(0) - event.getY(1)));
oneBeforeLastDistance = Math.sqrt((event.getHistoricalX(0, historySize - 1) - event.getHistoricalX(1, historySize - 1)) *
(event.getHistoricalX(0, historySize - 1) - event.getHistoricalX(1, historySize - 1)) +
(event.getHistoricalY(0, historySize - 1) - event.getHistoricalY(1, historySize - 1)) *
(event.getHistoricalY(0, historySize - 1) - event.getHistoricalY(1, historySize - 1)));
if (lastDistance < oneBeforeLastDistance) {
circle.radius -= Math.abs(lastDistance - oneBeforeLastDistance);
} else {
circle.radius += Math.abs(lastDistance - oneBeforeLastDistance);
}
}
}
lastCircleX = circle.centerX;
lastCircleY = circle.centerY;
invalidate();
break;
case MotionEvent.ACTION_POINTER_UP:
circle.centerX = lastCircleX;
circle.centerY = lastCircleY;
isPinchMode = false;
break;
case MotionEvent.ACTION_UP:
circle.centerX = lastCircleX;
circle.centerY = lastCircleY;
isPinchMode = false;
isDoneResizing = true;
break;
case MotionEvent.ACTION_CANCEL:
break;
case MotionEvent.ACTION_HOVER_MOVE:
break;
default:
super.onTouchEvent(event);
break;
}
return true;
}
private Boolean getTouchedCircle(final int xTouch, final int yTouch) {
if ((circle.centerX - xTouch) * (circle.centerX - xTouch) +
(circle.centerY - yTouch) * (circle.centerY - yTouch) <= circle.radius * circle.radius) {
return true;
} else {
return false;
}
}
static class Circle {
int radius;
int centerX;
int centerY;
Circle() {
this.radius = 150;
this.centerX = 378;
this.centerY = 478;
}
}
}
/*extends View {
private static final int MODE_PINCH = 0;
private static final int MODE_DONT_CARE = 1;
ShapeDrawable mCircleDrawable;
int mTouchMode = MODE_DONT_CARE;
public CircleTouchView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mCircleDrawable = new ShapeDrawable(new OvalShape());
mCircleDrawable.getPaint().setColor(0x66FFFFFF);
}
public CircleTouchView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CircleTouchView(Context context) {
this(context, null, 0);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
mCircleDrawable.setBounds(0, 0, 0, 0);
invalidate();
break;
case MotionEvent.ACTION_POINTER_DOWN:
prepareCircleDrawing(event);
break;
case MotionEvent.ACTION_MOVE:
if (mTouchMode == MODE_PINCH) {
prepareCircleDrawing(event);
}
break;
case MotionEvent.ACTION_POINTER_UP:
if (event.getActionIndex() <= 1) {
mTouchMode = MODE_DONT_CARE;
}
break;
default:
super.onTouchEvent(event);
}
return true;
}
private void prepareCircleDrawing(MotionEvent event) {
int top, right, bottom, left;
int index = event.getActionIndex();
if (index > 1) {
return;
}
mTouchMode = MODE_PINCH;
if (event.getX(0) < event.getX(1)) {
left = (int) event.getX(0);
right = (int) event.getX(1);
} else {
left = (int) event.getX(1);
right = (int) event.getX(0);
}
if (event.getY(0) < event.getY(1)) {
top = (int) event.getY(0);
bottom = (int) event.getY(1);
} else {
top = (int) event.getY(1);
bottom = (int) event.getY(0);
}
mCircleDrawable.setBounds(left, top, right, bottom);
invalidate();
}
@Override
protected void onDraw(Canvas canvas) {
mCircleDrawable.draw(canvas);
}
}
*/
Thanks in advance
来源：https://stackoverflow.com/questions/23954209/android-expand-and-shrink-circle-on-google-map