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Add javadoc for new location API's.

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Change-Id: If15024ee88421c07ba3a174747774fc451fd002e
This commit is contained in:
Nick Pelly
2012-08-13 19:35:39 -07:00
parent 74fa7eabda
commit 4e31c4fffb
8 changed files with 840 additions and 517 deletions
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300
location/java/android/location/LocationRequest.java
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@@ -21,24 +21,140 @@ import android.os.Parcelable;
import android.os.SystemClock;
import android.util.TimeUtils;
/**
* A data object that contains quality of service parameters for requests
* to the {@link LocationManager}.
*
* <p>LocationRequest objects are used to request a quality of service
* for location updates from the Location Manager.
*
* <p>For example, if your application wants high accuracy location
* it should create a location request with {@link #setQuality} set to
* {@link #ACCURACY_FINE} or {@link #POWER_HIGH}, and it should set
* {@link #setInterval} to less than one second. This would be
* appropriate for mapping applications that are showing your location
* in real-time.
*
* <p>At the other extreme, if you want negligible power
* impact, but to still receive location updates when available, then use
* {@link #setQuality} with {@link #POWER_NONE}. With this request your
* application will not trigger (and therefore will not receive any
* power blame) any location updates, but will receive locations
* triggered by other applications. This would be appropriate for
* applications that have no firm requirement for location, but can
* take advantage when available.
*
* <p>In between these two extremes is a very common use-case, where
* applications definitely want to receive
* updates at a specified interval, and can receive them faster when
* available, but still want a low power impact. These applications
* should consider {@link #POWER_LOW} combined with a faster
* {@link #setFastestInterval} (such as 1 minute) and a slower
* {@link #setInterval} (such as 60 minutes). They will only be assigned
* power blame for the interval set by {@link #setInterval}, but can
* still receive locations triggered by other applications at a rate up
* to {@link #setFastestInterval}. This style of request is appropriate for
* many location aware applications, including background usage. Do be
* careful to also throttle {@link #setFastestInterval} if you perform
* heavy-weight work after receiving an update - such as using the network.
*
* <p>Activities should strongly consider removing all location
* request when entering the background
* (for example at {@link android.app.Activity#onPause}), or
* at least swap the request to a larger interval and lower quality.
* Future version of the location manager may automatically perform background
* throttling on behalf of applications.
*
* <p>Applications cannot specify the exact location sources that are
* used by Android's <em>Fusion Engine</em>. In fact, the system
* may have multiple location sources (providers) running and may
* fuse the results from several sources into a single Location object.
*
* <p>Location requests from applications with
* {@link android.Manifest.permission#ACCESS_COARSE_LOCATION} and not
* {@link android.Manifest.permission#ACCESS_FINE_LOCATION} will
* be automatically throttled to a slower interval, and the location
* object will be obfuscated to only show a coarse level of accuracy.
*
* <p>All location requests are considered hints, and you may receive
* locations that are more accurate, less accurate, and slower
* than requested.
*/
public final class LocationRequest implements Parcelable {
// QOS control
public static final int ACCURACY_FINE = 100; // ~1 meter
public static final int ACCURACY_BLOCK = 102; // ~100 meters
public static final int ACCURACY_CITY = 104; // ~10 km
/**
* Used with {@link #setQuality} to request the most accurate locations available.
*
* <p>This may be up to 1 meter accuracy, although this is implementation dependent.
*/
public static final int ACCURACY_FINE = 100;
/**
* Used with {@link #setQuality} to request "block" level accuracy.
*
* <p>Block level accuracy is considered to be about 100 meter accuracy,
* although this is implementation dependent. Using a coarse accuracy
* such as this often consumes less power.
*/
public static final int ACCURACY_BLOCK = 102;
/**
* Used with {@link #setQuality} to request "city" level accuracy.
*
* <p>City level accuracy is considered to be about 10km accuracy,
* although this is implementation dependent. Using a coarse accuracy
* such as this often consumes less power.
*/
public static final int ACCURACY_CITY = 104;
/**
* Used with {@link #setQuality} to require no direct power impact (passive locations).
*
* <p>This location request will not trigger any active location requests,
* but will receive locations triggered by other applications. Your application
* will not receive any direct power blame for location work.
*/
public static final int POWER_NONE = 200;
/**
* Used with {@link #setQuality} to request low power impact.
*
* <p>This location request will avoid high power location work where
* possible.
*/
public static final int POWER_LOW = 201;
/**
* Used with {@link #setQuality} to allow high power consumption for location.
*
* <p>This location request will allow high power location work.
*/
public static final int POWER_HIGH = 203;
/**
* By default, mFastestInterval = FASTEST_INTERVAL_MULTIPLE * mInterval
*/
private static final double FASTEST_INTERVAL_FACTOR = 6.0; // 6x
private int mQuality = POWER_LOW;
private long mFastestInterval = 6 * 1000; // 6 seconds
private long mInterval = 60 * 1000; // 1 minute
private long mInterval = 60 * 60 * 1000; // 60 minutes
private long mFastestInterval = (long)(mInterval / FASTEST_INTERVAL_FACTOR); // 10 minutes
private boolean mExplicitFastestInterval = false;
private long mExpireAt = Long.MAX_VALUE; // no expiry
private int mNumUpdates = Integer.MAX_VALUE; // no expiry
private float mSmallestDisplacement = 0.0f; // meters
private String mProvider = null; // for deprecated API's that explicitly request a provider
/**
* Create a location request with default parameters.
*
* <p>Default parameters are for a low power, slowly updated location.
* It can then be adjusted as required by the applications before passing
* to the {@link LocationManager}
*
* @return a new location request
*/
public static LocationRequest create() {
LocationRequest request = new LocationRequest();
return request;
@@ -105,52 +221,217 @@ public final class LocationRequest implements Parcelable {
/** @hide */
public LocationRequest() { }
/**
* Set the quality of the request.
*
* <p>Use with a accuracy constant such as {@link #ACCURACY_FINE}, or a power
* constant such as {@link #POWER_LOW}. You cannot request both and accuracy and
* power, only one or the other can be specified. The system will then
* maximize accuracy or minimize power as appropriate.
*
* <p>The quality of the request is a strong hint to the system for which
* location sources to use. For example, {@link #ACCURACY_FINE} is more likely
* to use GPS, and {@link #POWER_LOW} is more likely to use WIFI & Cell tower
* positioning, but it also depends on many other factors (such as which sources
* are available) and is implementation dependent.
*
* <p>{@link #setQuality} and {@link #setInterval} are the most important parameters
* on a location request.
*
* @param quality an accuracy or power constant
* @throws InvalidArgumentException if the quality constant is not valid
* @return the same object, so that setters can be chained
*/
public LocationRequest setQuality(int quality) {
checkQuality(quality);
mQuality = quality;
return this;
}
/**
* Get the quality of the request.
*
* @return an accuracy or power constant
*/
public int getQuality() {
return mQuality;
}
/**
* Set the desired interval for active location updates, in milliseconds.
*
* <p>The location manager will actively try to obtain location updates
* for your application at this interval, so it has a
* direct influence on the amount of power used by your application.
* Choose your interval wisely.
*
* <p>This interval is inexact. You may not receive updates at all (if
* no location sources are available), or you may receive them
* slower than requested. You may also receive them faster than
* requested (if other applications are requesting location at a
* faster interval). The fastest rate that that you will receive
* updates can be controlled with {@link #setFastestInterval}.
*
* <p>Applications with only the coarse location permission may have their
* interval silently throttled.
*
* <p>An interval of 0 is allowed, but not recommended, since
* location updates may be extremely fast on future implementations.
*
* <p>{@link #setQuality} and {@link #setInterval} are the most important parameters
* on a location request.
*
* @param millis desired interval in millisecond, inexact
* @throws InvalidArgumentException if the interval is less than zero
* @return the same object, so that setters can be chained
*/
public LocationRequest setInterval(long millis) {
checkInterval(millis);
mInterval = millis;
if (!mExplicitFastestInterval) {
mFastestInterval = (long)(mInterval / FASTEST_INTERVAL_FACTOR);
}
return this;
}
/**
* Get the desired interval of this request, in milliseconds.
*
* @return desired interval in milliseconds, inexact
*/
public long getInterval() {
return mInterval;
}
/**
* Explicitly set the fastest interval for location updates, in
* milliseconds.
*
* <p>This controls the fastest rate at which your application will
* receive location updates, which might be faster than
* {@link #setInterval} in some situations (for example, if other
* applications are triggering location updates).
*
* <p>This allows your application to passively acquire locations
* at a rate faster than it actively acquires locations, saving power.
*
* <p>Unlike {@link #setInterval}, this parameter is exact. Your
* application will never receive updates faster than this value.
*
* <p>If you don't call this method, a fastest interval
* will be selected for you. It will be a value faster than your
* active interval ({@link #setInterval}).
*
* <p>An interval of 0 is allowed, but not recommended, since
* location updates may be extremely fast on future implementations.
*
* <p>If {@link #setFastestInterval} is set slower than {@link #setInterval},
* then your effective fastest interval is {@link #setInterval}.
*
* @param millis fastest interval for updates in milliseconds, exact
* @throws InvalidArgumentException if the interval is less than zero
* @return the same object, so that setters can be chained
*/
public LocationRequest setFastestInterval(long millis) {
checkInterval(millis);
mExplicitFastestInterval = true;
mFastestInterval = millis;
return this;
}
/**
* Get the fastest interval of this request, in milliseconds.
*
* <p>The system will never provide location updates faster
* than the minimum of {@link #getFastestInterval} and
* {@link #getInterval}.
*
* @return fastest interval in milliseconds, exact
*/
public long getFastestInterval() {
return mFastestInterval;
}
/**
* Set the duration of this request, in milliseconds.
*
* <p>The duration begins immediately (and not when the request
* is passed to the location manager), so call this method again
* if the request is re-used at a later time.
*
* <p>The location manager will automatically stop updates after
* the request expires.
*
* <p>The duration includes suspend time. Values less than 0
* are allowed, but indicate that the request has already expired.
*
* @param millis duration of request in milliseconds
* @return the same object, so that setters can be chained
*/
public LocationRequest setExpireIn(long millis) {
mExpireAt = millis + SystemClock.elapsedRealtime();
if (mExpireAt < 0) mExpireAt = 0;
return this;
}
/**
* Set the request expiration time, in millisecond since boot.
*
* <p>This expiration time uses the same time base as {@link SystemClock#elapsedRealtime}.
*
* <p>The location manager will automatically stop updates after
* the request expires.
*
* <p>The duration includes suspend time. Values before {@link SystemClock#elapsedRealtime}
* are allowed, but indicate that the request has already expired.
*
* @param millis expiration time of request, in milliseconds since boot including suspend
* @return the same object, so that setters can be chained
*/
public LocationRequest setExpireAt(long millis) {
mExpireAt = millis;
if (mExpireAt < 0) mExpireAt = 0;
return this;
}
/**
* Get the request expiration time, in milliseconds since boot.
*
* <p>This value can be compared to {@link SystemClock#elapsedRealtime} to determine
* the time until expiration.
*
* @return expiration time of request, in milliseconds since boot including suspend
*/
public long getExpireAt() {
return mExpireAt;
}
/**
* Set the number of location updates.
*
* <p>By default locations are continuously updated until the request is explicitly
* removed, however you can optionally request a set number of updates.
* For example, if your application only needs a single fresh location,
* then call this method with a value of 1 before passing the request
* to the location manager.
*
* @param numUpdates the number of location updates requested
* @throws InvalidArgumentException if numUpdates is 0 or less
* @return the same object, so that setters can be chained
*/
public LocationRequest setNumUpdates(int numUpdates) {
if (numUpdates <= 0) throw new IllegalArgumentException("invalid numUpdates: " + numUpdates);
mNumUpdates = numUpdates;
return this;
}
/**
* Get the number of updates requested.
*
* <p>By default this is {@link Integer#MAX_VALUE}, which indicates that
* locations are updated until the request is explicitly removed.
* @return number of updates
*/
public int getNumUpdates() {
return mNumUpdates;
}
@@ -165,11 +446,6 @@ public final class LocationRequest implements Parcelable {
}
}
public LocationRequest setNumUpdates(int numUpdates) {
if (numUpdates < 0) throw new IllegalArgumentException("invalid numUpdates: " + numUpdates);
mNumUpdates = numUpdates;
return this;
}
/** @hide */
public LocationRequest setProvider(String provider) {
@@ -247,10 +523,12 @@ public final class LocationRequest implements Parcelable {
return new LocationRequest[size];
}
};
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel parcel, int flags) {
parcel.writeInt(mQuality);