CronetEngine

The value of the active request count is unknown

The value of a connection metric is unknown.

The estimate of the effective connection type is 2G.

The estimate of the effective connection type is 3G.

The estimate of the effective connection type is 4G.

The device is offline.

The estimate of the effective connection type is slow 2G.

The estimate of the effective connection type is unknown.

The value to be used to undo any previous network binding.

Registers a listener that gets called after the end of each request with the request info.

The listener is called on an Executor provided by the listener.

Registers a listener that gets called whenever the network quality estimator witnesses a sample round trip time. This must be called after enableNetworkQualityEstimator(boolean), and with throw an exception otherwise. Round trip times may be recorded at various layers of the network stack, including TCP, QUIC, and at the URL request layer. The listener is called on the Executor that is passed to enableNetworkQualityEstimator(boolean).

Registers a listener that gets called whenever the network quality estimator witnesses a sample throughput measurement. This must be called after enableNetworkQualityEstimator(boolean). Throughput observations are computed by measuring bytes read over the active network interface at times when at least one URL response is being received. The listener is called on the Executor that is passed to enableNetworkQualityEstimator(boolean).

Binds the engine to the specified network handle. All requests created through this engine will use the network associated to this handle. If this network disconnects all requests will fail, the exact error will depend on the stage of request processing when the network disconnects. Network handles can be obtained through Network#getNetworkHandle. Only available starting from Android Marshmallow.

Configures the network quality estimator for testing. This must be called before round trip time and throughput listeners are added, and after the network quality estimator has been enabled.

Creates a URLStreamHandlerFactory to handle HTTP and HTTPS traffic. An instance of this class can be installed via setURLStreamHandlerFactory(URLStreamHandlerFactory) thus using this CronetEngine by default for all requests created via openConnection().

Cronet does not use certain HTTP features provided via the system:

• the HTTP cache installed via HttpResponseCache.install()
• the HTTP authentication method installed via setDefault(Authenticator)
• the HTTP cookie storage installed via setDefault(CookieHandler)

While Cronet supports and encourages requests using the HTTPS protocol, Cronet does not provide support for the HttpsURLConnection API. This lack of support also includes not using certain HTTPS features provided via the system:

• the HTTPS hostname verifier installed via HttpsURLConnection.setDefaultHostnameVerifier()
• the HTTPS socket factory installed via HttpsURLConnection.setDefaultSSLSocketFactory()

Returns the number of active requests.

A request becomes "active" in UrlRequest.start(), assuming that method does not throw an exception. It becomes inactive when all callbacks have returned and no additional callbacks can be triggered in the future. In practice, that means the request is inactive once onSucceeded/onCanceled/onFailed has returned and all request finished listeners have returned. Cronet requests's lifecycle for more information.

Returns the downstream throughput estimate (in kilobits per second) computed by the network quality estimator. Set to CONNECTION_METRIC_UNKNOWN if the value is unavailable. This must be called after enableNetworkQualityEstimator(boolean), and will throw an exception otherwise.

Returns an estimate of the effective connection type computed by the network quality estimator. Call enableNetworkQualityEstimator(boolean) to begin computing this value.

Returns differences in metrics collected by Cronet since the last call to this method.

Cronet collects these metrics globally. This means deltas returned by getGlobalMetricsDeltas() will include measurements of requests processed by other CronetEngine instances. Since this function returns differences in metrics collected since the last call, and these metrics are collected globally, a call to any CronetEngine instance's getGlobalMetricsDeltas() method will affect the deltas returned by any other CronetEngine instance's getGlobalMetricsDeltas().

Cronet starts collecting these metrics after the first call to getGlobalMetricsDeltras(), so the first call returns no useful data as no metrics have yet been collected.

Returns the HTTP RTT estimate (in milliseconds) computed by the network quality estimator. Set to CONNECTION_METRIC_UNKNOWN if the value is unavailable. This must be called after enableNetworkQualityEstimator(boolean), and will throw an exception otherwise.

Returns the transport RTT estimate (in milliseconds) computed by the network quality estimator. Set to CONNECTION_METRIC_UNKNOWN if the value is unavailable. This must be called after enableNetworkQualityEstimator(boolean), and will throw an exception otherwise.

Creates a builder for UrlRequest. All callbacks for generated UrlRequest objects will be invoked on executor's threads. executor must not run tasks on the thread calling execute(Runnable) to prevent blocking networking operations and causing exceptions during shutdown.

Establishes a new connection to the resource specified by the URL url.

Note: Cronet's HttpURLConnection implementation is subject to certain limitations, see createURLStreamHandlerFactory() for details.

Removes a finished request listener.

Removes a listener of round trip times if previously registered with addRttListener(NetworkQualityRttListener). This should be called after a NetworkQualityRttListener is added in order to stop receiving observations.

Removes a listener of throughput. This should be called after a NetworkQualityThroughputListener is added with addThroughputListener(NetworkQualityThroughputListener) in order to stop receiving observations.

Shuts down the CronetEngine if there are no active requests, otherwise throws an exception.

Cannot be called on network thread - the thread Cronet calls into Executor on (which is different from the thread the Executor invokes callbacks on). May block until all the CronetEngine's resources have been cleaned up.

Starts NetLog logging to a specified directory with a bounded size. The NetLog will contain events emitted by all live CronetEngines. The NetLog is useful for debugging. Once logging has stopped stopNetLog(), the data will be written to netlog.json in dirPath. If logging is interrupted, you can stitch the files found in .inprogress subdirectory manually using: https://chromium.googlesource.com/chromium/src/+/main/net/tools/stitch_net_log_files.py. The log can be viewed using a Chrome browser navigated to chrome://net-internals/#import.

Starts NetLog logging to a file. The NetLog will contain events emitted by all live CronetEngines. The NetLog is useful for debugging. The file can be viewed using a Chrome browser navigated to chrome://net-internals/#import

Stops NetLog logging and flushes file to disk. If a logging session is not in progress, this call is ignored.