CarConnection.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.car.app.connection;
import static androidx.annotation.RestrictTo.Scope.LIBRARY;
import static androidx.car.app.utils.CommonUtils.isAutomotiveOS;
import static java.util.Objects.requireNonNull;
import android.content.Context;
import androidx.annotation.IntDef;
import androidx.annotation.MainThread;
import androidx.annotation.NonNull;
import androidx.annotation.RestrictTo;
import androidx.lifecycle.LiveData;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
/**
* A class that allows retrieval of information about connection to a car head unit.
*/
public final class CarConnection {
/**
* Defines current car connection state.
*
* <p>This is used for communication with the car host's content provider on queries for
* connection type.
*/
public static final String CAR_CONNECTION_STATE = "CarConnectionState";
/**
* Broadcast action that notifies that the car connection has changed and needs to be updated.
*/
public static final String ACTION_CAR_CONNECTION_UPDATED =
"androidx.car.app.connection.action.CAR_CONNECTION_UPDATED";
/**
* Represents the types of connections that exist to a car head unit.
*
*/
@IntDef({CONNECTION_TYPE_NOT_CONNECTED, CONNECTION_TYPE_NATIVE, CONNECTION_TYPE_PROJECTION})
@Retention(RetentionPolicy.SOURCE)
@Target({ElementType.TYPE_USE})
@RestrictTo(LIBRARY)
public @interface ConnectionType {
}
/**
* Not connected to any car head unit.z
*/
public static final int CONNECTION_TYPE_NOT_CONNECTED = 0;
/**
* Natively running on a head unit (Android Automotive OS).
*/
public static final int CONNECTION_TYPE_NATIVE = 1;
/**
* Connected to a car head unit by projecting to it.
*/
public static final int CONNECTION_TYPE_PROJECTION = 2;
private final LiveData<Integer> mConnectionTypeLiveData;
/**
* Constructs a {@link CarConnection} that can be used to get connection information.
*
* @throws NullPointerException if {@code context} is {@code null}
*/
@MainThread
public CarConnection(@NonNull Context context) {
requireNonNull(context);
mConnectionTypeLiveData = isAutomotiveOS(context)
? new AutomotiveCarConnectionTypeLiveData()
: new CarConnectionTypeLiveData(context);
}
/**
* Returns a {@link LiveData} that can be observed to get current connection type.
*
* <p>The recommended pattern is to observe the {@link LiveData} with the activity's
* lifecycle in order to get updates on the state change throughout the activity's lifetime.
*
* <p>Connection types are:
* <ol>
* <li>{@link #CONNECTION_TYPE_NOT_CONNECTED}
* <li>{@link #CONNECTION_TYPE_NATIVE}
* <li>{@link #CONNECTION_TYPE_PROJECTION}
* </ol>
*/
@NonNull
public LiveData<@ConnectionType Integer> getType() {
return mConnectionTypeLiveData;
}
}