LocationCompat.java
/*
* Copyright 2021 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package androidx.core.location;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.NANOSECONDS;
import android.location.Location;
import android.os.Build.VERSION;
import android.os.Bundle;
import android.os.SystemClock;
import androidx.annotation.DoNotInline;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.RequiresApi;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
/**
* Helper for accessing features in {@link android.location.Location}.
*/
public final class LocationCompat {
private static final String EXTRA_IS_MOCK = "mockLocation";
@Nullable
private static Method sSetIsFromMockProviderMethod;
private LocationCompat() {}
/**
* Return the time of this fix, in nanoseconds of elapsed real-time since system boot.
*
* <p>This value can be reliably compared to SystemClock.elapsedRealtimeNanos(), to calculate
* the age of a fix and to compare location fixes. This is reliable because elapsed real-time
* is guaranteed monotonic for each system boot and continues to increment even when the
* system is in deep sleep (unlike getTime().
*
* <p>All locations generated by the LocationManager are guaranteed to have a valid elapsed
* real-time.
*
* <p>NOTE: On API levels below 17, this method will attempt to provide an elapsed realtime
* based on the difference between system time and the location time. This should be taken as a
* best "guess" at what the elapsed realtime might have been, but if the clock used for
* location derivation is different from the system clock, the results may be inaccurate.
*/
public static long getElapsedRealtimeNanos(@NonNull Location location) {
if (VERSION.SDK_INT >= 17) {
return Api17Impl.getElapsedRealtimeNanos(location);
} else {
return MILLISECONDS.toNanos(getElapsedRealtimeMillis(location));
}
}
/**
* Return the time of this fix, in milliseconds of elapsed real-time since system boot.
*
* @see #getElapsedRealtimeNanos(Location)
*/
public static long getElapsedRealtimeMillis(@NonNull Location location) {
if (VERSION.SDK_INT >= 17) {
return NANOSECONDS.toMillis(Api17Impl.getElapsedRealtimeNanos(location));
} else {
long timeDeltaMs = System.currentTimeMillis() - location.getTime();
long elapsedRealtimeMs = SystemClock.elapsedRealtime();
if (timeDeltaMs < 0) {
// don't return an elapsed realtime from the future
return elapsedRealtimeMs;
} else if (timeDeltaMs > elapsedRealtimeMs) {
// don't return an elapsed realtime from before boot
return 0;
} else {
return elapsedRealtimeMs - timeDeltaMs;
}
}
}
/**
* Returns true if this location is marked as a mock location. If this location comes from the
* Android framework, this indicates that the location was provided by a test location provider,
* and thus may not be related to the actual location of the device.
*
* <p>NOTE: On API levels below 18, the concept of a mock location does not exist. In order to
* allow for backwards compatibility and testing however, this method will attempt to read a
* boolean extra with the key "mockLocation" and use the result to determine whether this should
* be considered a mock location.
*
* @see android.location.LocationManager#addTestProvider
*/
public static boolean isMock(@NonNull Location location) {
if (VERSION.SDK_INT >= 18) {
return Api18Impl.isMock(location);
} else {
Bundle extras = location.getExtras();
if (extras == null) {
return false;
}
return extras.getBoolean(EXTRA_IS_MOCK, false);
}
}
/**
* Sets whether this location is marked as a mock location.
*
* <p>NOTE: On API levels below 18, the concept of a mock location does not exist. In order to
* allow for backwards compatibility and testing however, this method will attempt to set a
* boolean extra with the key "mockLocation" to mark the location as mock. Be aware that this
* will overwrite any prior extra value under the same key.
*/
public static void setMock(@NonNull Location location, boolean mock) {
if (VERSION.SDK_INT >= 18) {
try {
getSetIsFromMockProviderMethod().invoke(location, mock);
} catch (NoSuchMethodException e) {
Error error = new NoSuchMethodError();
error.initCause(e);
throw error;
} catch (IllegalAccessException e) {
Error error = new IllegalAccessError();
error.initCause(e);
throw error;
} catch (InvocationTargetException e) {
throw new RuntimeException(e);
}
} else {
Bundle extras = location.getExtras();
if (extras == null) {
extras = new Bundle();
extras.putBoolean(EXTRA_IS_MOCK, true);
location.setExtras(extras);
} else {
extras.putBoolean(EXTRA_IS_MOCK, true);
}
}
}
@RequiresApi(18)
private static class Api18Impl {
private Api18Impl() {}
@DoNotInline
static boolean isMock(Location location) {
return location.isFromMockProvider();
}
}
@RequiresApi(17)
private static class Api17Impl {
private Api17Impl() {}
@DoNotInline
static long getElapsedRealtimeNanos(Location location) {
return location.getElapsedRealtimeNanos();
}
}
private static Method getSetIsFromMockProviderMethod() throws NoSuchMethodException {
if (sSetIsFromMockProviderMethod == null) {
sSetIsFromMockProviderMethod = Location.class.getDeclaredMethod("setIsFromMockProvider",
boolean.class);
sSetIsFromMockProviderMethod.setAccessible(true);
}
return sSetIsFromMockProviderMethod;
}
}