public final class ComponentName extends Object implements Parcelable, Cloneable, Comparable<ComponentName>
Activity
, Service
,
BroadcastReceiver
, or
ContentProvider
) that is available. Two
pieces of information, encapsulated here, are required to identify
a component: the package (a String) it exists in, and the class (a String)
name inside of that package.Parcelable.ClassLoaderCreator<T>, Parcelable.Creator<T>
Modifier and Type | Field and Description |
---|---|
static Parcelable.Creator<ComponentName> |
CREATOR |
CONTENTS_FILE_DESCRIPTOR, PARCELABLE_ELIDE_DUPLICATES, PARCELABLE_WRITE_RETURN_VALUE
Constructor and Description |
---|
ComponentName(Context pkg,
Class<?> cls)
Create a new component identifier from a Context and Class object.
|
ComponentName(Context pkg,
String cls)
Create a new component identifier from a Context and class name.
|
ComponentName(Parcel in)
Instantiate a new ComponentName from the data in a Parcel that was
previously written with
writeToParcel(Parcel, int) . |
ComponentName(String pkg,
String cls)
Create a new component identifier.
|
Modifier and Type | Method and Description |
---|---|
void |
appendShortString(StringBuilder sb) |
static void |
appendShortString(StringBuilder sb,
String packageName,
String className) |
ComponentName |
clone()
Creates and returns a copy of this object.
|
int |
compareTo(ComponentName that)
Compares this object with the specified object for order.
|
static ComponentName |
createRelative(Context pkg,
String cls)
Create a new component identifier where the class name may be specified
as either absolute or relative to the containing package.
|
static ComponentName |
createRelative(String pkg,
String cls)
Create a new component identifier where the class name may be specified
as either absolute or relative to the containing package.
|
int |
describeContents()
Describe the kinds of special objects contained in this Parcelable
instance's marshaled representation.
|
boolean |
equals(Object obj)
Indicates whether some other object is "equal to" this one.
|
String |
flattenToShortString()
The same as
flattenToString() , but abbreviates the class
name if it is a suffix of the package. |
String |
flattenToString()
Return a String that unambiguously describes both the package and
class names contained in the ComponentName.
|
String |
getClassName()
Return the class name of this component.
|
String |
getPackageName()
Return the package name of this component.
|
String |
getShortClassName()
Return the class name, either fully qualified or in a shortened form
(with a leading '.') if it is a suffix of the package.
|
int |
hashCode()
Returns a hash code value for the object.
|
static void |
printShortString(PrintWriter pw,
String packageName,
String className) |
static ComponentName |
readFromParcel(Parcel in)
Read a ComponentName from a Parcel that was previously written
with
writeToParcel(ComponentName, Parcel) , returning either
a null or new object as appropriate. |
String |
toShortString()
Return string representation of this class without the class's name
as a prefix.
|
String |
toString()
Returns a string representation of the object.
|
static ComponentName |
unflattenFromString(String str)
Recover a ComponentName from a String that was previously created with
flattenToString() . |
static void |
writeToParcel(ComponentName c,
Parcel out)
Write a ComponentName to a Parcel, handling null pointers.
|
void |
writeToParcel(Parcel out,
int flags)
Flatten this object in to a Parcel.
|
public static final Parcelable.Creator<ComponentName> CREATOR
public ComponentName(String pkg, String cls)
pkg
- The name of the package that the component exists in. Can
not be null.cls
- The name of the class inside of pkg that
implements the component. Can not be null.public ComponentName(Context pkg, String cls)
pkg
- A Context for the package implementing the component,
from which the actual package name will be retrieved.cls
- The name of the class inside of pkg that
implements the component.public ComponentName(Context pkg, Class<?> cls)
pkg
- A Context for the package implementing the component, from
which the actual package name will be retrieved.cls
- The Class object of the desired component, from which the
actual class name will be retrieved.public ComponentName(Parcel in)
writeToParcel(Parcel, int)
. Note that you
must not use this with data written by
writeToParcel(ComponentName, Parcel)
since it is not possible
to handle a null ComponentObject here.in
- The Parcel containing the previously written ComponentName,
positioned at the location in the buffer where it was written.public static ComponentName createRelative(String pkg, String cls)
Relative package names begin with a '.'
character. For a package
"com.example"
and class name ".app.MyActivity"
this method
will return a ComponentName with the package "com.example"
and class name
"com.example.app.MyActivity"
. Fully qualified class names are also
permitted.
pkg
- the name of the package the component exists incls
- the name of the class inside of pkg that implements
the componentpublic static ComponentName createRelative(Context pkg, String cls)
Relative package names begin with a '.'
character. For a package
"com.example"
and class name ".app.MyActivity"
this method
will return a ComponentName with the package "com.example"
and class name
"com.example.app.MyActivity"
. Fully qualified class names are also
permitted.
pkg
- a Context for the package implementing the componentcls
- the name of the class inside of pkg that implements
the componentpublic ComponentName clone()
Object
x
, the expression:
will be true, and that the expression:x.clone() != x
will bex.clone().getClass() == x.getClass()
true
, but these are not absolute requirements.
While it is typically the case that:
will bex.clone().equals(x)
true
, this is not an absolute requirement.
By convention, the returned object should be obtained by calling
super.clone
. If a class and all of its superclasses (except
Object
) obey this convention, it will be the case that
x.clone().getClass() == x.getClass()
.
By convention, the object returned by this method should be independent
of this object (which is being cloned). To achieve this independence,
it may be necessary to modify one or more fields of the object returned
by super.clone
before returning it. Typically, this means
copying any mutable objects that comprise the internal "deep structure"
of the object being cloned and replacing the references to these
objects with references to the copies. If a class contains only
primitive fields or references to immutable objects, then it is usually
the case that no fields in the object returned by super.clone
need to be modified.
The method clone
for class Object
performs a
specific cloning operation. First, if the class of this object does
not implement the interface Cloneable
, then a
CloneNotSupportedException
is thrown. Note that all arrays
are considered to implement the interface Cloneable
and that
the return type of the clone
method of an array type T[]
is T[]
where T is any reference or primitive type.
Otherwise, this method creates a new instance of the class of this
object and initializes all its fields with exactly the contents of
the corresponding fields of this object, as if by assignment; the
contents of the fields are not themselves cloned. Thus, this method
performs a "shallow copy" of this object, not a "deep copy" operation.
The class Object
does not itself implement the interface
Cloneable
, so calling the clone
method on an object
whose class is Object
will result in throwing an
exception at run time.
public String getPackageName()
public String getClassName()
public String getShortClassName()
public String flattenToString()
unflattenFromString(String)
.unflattenFromString(String)
public String flattenToShortString()
flattenToString()
, but abbreviates the class
name if it is a suffix of the package. The result can still be used
with unflattenFromString(String)
.unflattenFromString(String)
public void appendShortString(StringBuilder sb)
public static void appendShortString(StringBuilder sb, String packageName, String className)
public static void printShortString(PrintWriter pw, String packageName, String className)
public static ComponentName unflattenFromString(String str)
flattenToString()
. It splits the string at the first '/',
taking the part before as the package name and the part after as the
class name. As a special convenience (to use, for example, when
parsing component names on the command line), if the '/' is immediately
followed by a '.' then the final class name will be the concatenation
of the package name with the string following the '/'. Thus
"com.foo/.Blah" becomes package="com.foo" class="com.foo.Blah".str
- The String that was returned by flattenToString().flattenToString()
public String toShortString()
public String toString()
Object
toString
method returns a string that
"textually represents" this object. The result should
be a concise but informative representation that is easy for a
person to read.
It is recommended that all subclasses override this method.
The toString
method for class Object
returns a string consisting of the name of the class of which the
object is an instance, the at-sign character `@
', and
the unsigned hexadecimal representation of the hash code of the
object. In other words, this method returns a string equal to the
value of:
getClass().getName() + '@' + Integer.toHexString(hashCode())
public boolean equals(Object obj)
Object
The equals
method implements an equivalence relation
on non-null object references:
x
, x.equals(x)
should return
true
.
x
and y
, x.equals(y)
should return true
if and only if
y.equals(x)
returns true
.
x
, y
, and z
, if
x.equals(y)
returns true
and
y.equals(z)
returns true
, then
x.equals(z)
should return true
.
x
and y
, multiple invocations of
x.equals(y)
consistently return true
or consistently return false
, provided no
information used in equals
comparisons on the
objects is modified.
x
,
x.equals(null)
should return false
.
The equals
method for class Object
implements
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values x
and
y
, this method returns true
if and only
if x
and y
refer to the same object
(x == y
has the value true
).
Note that it is generally necessary to override the hashCode
method whenever this method is overridden, so as to maintain the
general contract for the hashCode
method, which states
that equal objects must have equal hash codes.
equals
in class Object
obj
- the reference object with which to compare.true
if this object is the same as the obj
argument; false
otherwise.Object.hashCode()
,
HashMap
public int hashCode()
Object
HashMap
.
The general contract of hashCode
is:
hashCode
method
must consistently return the same integer, provided no information
used in equals
comparisons on the object is modified.
This integer need not remain consistent from one execution of an
application to another execution of the same application.
equals(Object)
method, then calling the hashCode
method on each of
the two objects must produce the same integer result.
Object.equals(java.lang.Object)
method, then calling the hashCode
method on each of the
two objects must produce distinct integer results. However, the
programmer should be aware that producing distinct integer results
for unequal objects may improve the performance of hash tables.
As much as is reasonably practical, the hashCode method defined by
class Object
does return distinct integers for distinct
objects. (This is typically implemented by converting the internal
address of the object into an integer, but this implementation
technique is not required by the
JavaTM programming language.)
hashCode
in class Object
Object.equals(java.lang.Object)
,
System.identityHashCode(java.lang.Object)
public int compareTo(ComponentName that)
Comparable
The implementor must ensure sgn(x.compareTo(y)) == -sgn(y.compareTo(x)) for all x and y. (This implies that x.compareTo(y) must throw an exception iff y.compareTo(x) throws an exception.)
The implementor must also ensure that the relation is transitive: (x.compareTo(y)>0 && y.compareTo(z)>0) implies x.compareTo(z)>0.
Finally, the implementor must ensure that x.compareTo(y)==0 implies that sgn(x.compareTo(z)) == sgn(y.compareTo(z)), for all z.
It is strongly recommended, but not strictly required that (x.compareTo(y)==0) == (x.equals(y)). Generally speaking, any class that implements the Comparable interface and violates this condition should clearly indicate this fact. The recommended language is "Note: this class has a natural ordering that is inconsistent with equals."
In the foregoing description, the notation sgn(expression) designates the mathematical signum function, which is defined to return one of -1, 0, or 1 according to whether the value of expression is negative, zero or positive.
compareTo
in interface Comparable<ComponentName>
that
- the object to be compared.public int describeContents()
Parcelable
Parcelable.writeToParcel(Parcel, int)
,
the return value of this method must include the
Parcelable.CONTENTS_FILE_DESCRIPTOR
bit.describeContents
in interface Parcelable
Parcelable.CONTENTS_FILE_DESCRIPTOR
public void writeToParcel(Parcel out, int flags)
Parcelable
writeToParcel
in interface Parcelable
out
- The Parcel in which the object should be written.flags
- Additional flags about how the object should be written.
May be 0 or Parcelable.PARCELABLE_WRITE_RETURN_VALUE
.public static void writeToParcel(ComponentName c, Parcel out)
readFromParcel(Parcel)
.c
- The ComponentName to be written.out
- The Parcel in which the ComponentName will be placed.readFromParcel(Parcel)
public static ComponentName readFromParcel(Parcel in)
writeToParcel(ComponentName, Parcel)
, returning either
a null or new object as appropriate.in
- The Parcel from which to read the ComponentNamewriteToParcel(ComponentName, Parcel)