Trace

Kotlin |Java

public final class Trace
extends Object

java.lang.Object
↳	android.os.Trace

Writes trace events to the system trace buffer. These trace events can be collected and visualized using the Systrace tool.

This tracing mechanism is independent of the method tracing mechanism offered by Debug.startMethodTracing. In particular, it enables tracing of events that occur across multiple processes.

For information about using the Systrace tool, read Analyzing Display and Performance with Systrace.

Summary

Public methods
`static void`	`beginAsyncSection(String methodName, int cookie)` Writes a trace message to indicate that a given section of code has begun.
`static void`	`beginSection(String sectionName)` Writes a trace message to indicate that a given section of code has begun.
`static void`	`endAsyncSection(String methodName, int cookie)` Writes a trace message to indicate that the current method has ended.
`static void`	`endSection()` Writes a trace message to indicate that a given section of code has ended.
`static boolean`	`isEnabled()` Checks whether or not tracing is currently enabled.
`static void`	`setCounter(String counterName, long counterValue)` Writes trace message to indicate the value of a given counter.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class<?>`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

Public methods

beginAsyncSection

Added in API level 29

public static void beginAsyncSection (String methodName, 
                int cookie)

Writes a trace message to indicate that a given section of code has begun. Must be followed by a call to endAsyncSection(java.lang.String, int) with the same methodName and cookie. Unlike beginSection(java.lang.String) and endSection(), asynchronous events do not need to be nested. The name and cookie used to begin an event must be used to end it.

Parameters
`methodName`	`String`: The method name to appear in the trace. This value cannot be `null`.
`cookie`	`int`: Unique identifier for distinguishing simultaneous events

beginSection

Added in API level 18

public static void beginSection (String sectionName)

Writes a trace message to indicate that a given section of code has begun. This call must be followed by a corresponding call to endSection() on the same thread.

At this time the vertical bar character '|', newline character '\n', and null character '\0' are used internally by the tracing mechanism. If sectionName contains these characters they will be replaced with a space character in the trace.

Parameters
`sectionName`	`String`: The name of the code section to appear in the trace. This may be at most 127 Unicode code units long. This value cannot be `null`.

Throws
`IllegalArgumentException`	if `sectionName` is too long.

endAsyncSection

Added in API level 29

public static void endAsyncSection (String methodName, 
                int cookie)

Writes a trace message to indicate that the current method has ended. Must be called exactly once for each call to beginAsyncSection(java.lang.String, int) using the same name and cookie.

Parameters
`methodName`	`String`: The method name to appear in the trace. This value cannot be `null`.
`cookie`	`int`: Unique identifier for distinguishing simultaneous events

endSection

Added in API level 18

public static void endSection ()

Writes a trace message to indicate that a given section of code has ended. This call must be preceeded by a corresponding call to beginSection(java.lang.String). Calling this method will mark the end of the most recently begun section of code, so care must be taken to ensure that beginSection / endSection pairs are properly nested and called from the same thread.

isEnabled

Added in API level 29

public static boolean isEnabled ()

Checks whether or not tracing is currently enabled. This is useful to avoid intermediate string creation for trace sections that require formatting. It is not necessary to guard all Trace method calls as they internally already check this. However it is recommended to use this to prevent creating any temporary objects that would then be passed to those methods to reduce runtime cost when tracing isn't enabled.

Returns
`boolean`	true if tracing is currently enabled, false otherwise

setCounter

Added in API level 29

public static void setCounter (String counterName, 
                long counterValue)

Writes trace message to indicate the value of a given counter.

Parameters
`counterName`	`String`: The counter name to appear in the trace. This value cannot be `null`.
`counterValue`	`long`: The counter value.