Reference:Android.os.Message

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android.os
public final class android.os.Message

java.lang.Object
android.os.Message Parcelable

Defines a message containing a description and arbitrary data object that can be sent to a Handler. This object contains two extra int fields and an extra object field that allow you to not do allocations in many cases.

While the constructor of Message is public, the best way to get one of these is to call Message.obtain() or one of the Handler.obtainMessage() methods, which will pull them from a pool of recycled objects.

Contents

[edit] Summary

[edit] Constants

      Value  
Creator   CREATOR        

[edit] Fields

public      int  arg1   arg1 and arg2 are lower-cost alternatives to using setData() if you only need to store a few integer values.  
public      int  arg2   arg1 and arg2 are lower-cost alternatives to using setData() if you only need to store a few integer values.  
public      Runnable   callback   A callback object to receive the message.  
public      Object   obj   An arbitrary object to send to the recipient.  
public      Handler   target   A Handler implementation that will receive this message.  
public      int  what   User-defined message code so that the recipient can identify what this message is about.  
public      long  when   The targeted delivery time of this message,in milliseconds from now.  

[edit] Public Constructors

          Message ()
Constructor (but the preferred way to get a Message is to call Message.obtain() ).

[edit] Public Methods

        void  copyFrom (Message o)
Make this message like o.
        HashMap   getData ()
Obtains a HashMap of arbitrary data associated with this event, lazily creating it if necessary.
      static  Message   obtain ()
Return a new Message instance from the global pool.
      static  Message   obtain (Handler h)
Same as obtain(), but sets the value for the target member on the Message returned.
      static  Message   obtain (Handler h, int what, int arg1, int arg2)
Same as obtain(), but sets the values of the target, what, arg1, and arg2 members.
      static  Message   obtain (Handler h, int what)
Same as obtain(), but sets the values for both target andwhat members on the Message.
      static  Message   obtain (Handler h, int what, Object obj)
Same as obtain(), but sets the values of the target, what, and objmembers.
      static  Message   obtain (Handler h, int what, int arg1, int arg2, Object obj)
Same as obtain(), but sets the values of the target, what, arg1, arg2, and obj members.
        HashMap   peekData ()
Like getData(), but does not lazily create the HashMap.
        void  recycle ()
Return a Message instance to the global pool.
        void  sendToTarget ()
Sends this Message to the Handler specified by target.
        void  setData (HashMap data)
Sets a HashMap of arbitrary data values.
        String   toString ()
Answers a string containing a concise, human-readable description of the receiver.
        void  writeToParcel (Parcel dest)

[edit] Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
[edit] Methods inherited from interface android.os.Parcelable

writeToParcel

[edit] Details

[edit] Constants

[edit] public static final Creator CREATOR

[edit] Fields

[edit] public int arg1

arg1 and arg2 are lower-cost alternatives to using setData() if you only need to store a few integer values.

[edit] public int arg2

arg1 and arg2 are lower-cost alternatives to using setData() if you only need to store a few integer values.

[edit] public Runnable callback

A callback object to receive the message. This object must implement Runnable. This is called by the target Handler that is receiving this Message to dispatch it. If not set, the message will be dispatched to the receiving Handler's handleMessage(Message).

[edit] public Object obj

An arbitrary object to send to the recipient.

[edit] public Handler target

A Handler implementation that will receive this message. The object must implement Handler.handleMessage(). Each Handler has its own name-space for message codes, so you do not need to worry about yours conflicting with other handlers.

[edit] public int what

User-defined message code so that the recipient can identify what this message is about. Each Handler has its own name-space for message codes, so you do not need to worry about yours conflicting with other handlers.

[edit] public long when

The targeted delivery time of this message,in milliseconds from now.

[edit] Public Constructors

[edit] public Message()

Constructor (but the preferred way to get a Message is to call Message.obtain() ).

[edit] Public Methods

[edit] public void copyFrom(Message o)

Make this message like o. Performs a shallow copy of the data field. Does not copy the linked list fields.

[edit] public HashMap getData()

Obtains a HashMap of arbitrary data associated with this event, lazily creating it if necessary. Set this value by calling setData(HashMap).

[edit] public static Message obtain()

Return a new Message instance from the global pool. Allows us to avoid allocating new Java objects in many cases.

[edit] public static Message obtain(Handler h)

Same as obtain(), but sets the value for the target member on the Message returned.

Parameters

h Handler to assign to the returned Message object's target member.

Returns

  • A Message object from the global pool.

[edit] public static Message obtain(Handler h, int what, int arg1, int arg2)

Same as obtain(), but sets the values of the target, what, arg1, and arg2 members.

Parameters

h The target value to set.
what The what value to set.
arg1 The arg1 value to set.
arg2 The arg2 value to set.

Returns

  • A Message object from the global pool.

[edit] public static Message obtain(Handler h, int what)

Same as obtain(), but sets the values for both target andwhat members on the Message.

Parameters

h Value to assign to the target member.
what Value to assign to the what member.

Returns

  • A Message object from the global pool.

[edit] public static Message obtain(Handler h, int what, Object obj)

Same as obtain(), but sets the values of the target, what, and objmembers.

Parameters

h The target value to set.
what The what value to set.
obj The object method to set.

Returns

  • A Message object from the global pool.

[edit] public static Message obtain(Handler h, int what, int arg1, int arg2, Object obj)

Same as obtain(), but sets the values of the target, what, arg1, arg2, and obj members.

Parameters

h The target value to set.
what The what value to set.
arg1 The arg1 value to set.
arg2 The arg2 value to set.
obj The obj value to set.

Returns

  • A Message object from the global pool.

[edit] public HashMap peekData()

Like getData(), but does not lazily create the HashMap. A null is returned if the HashMap does not already exist.

[edit] public void recycle()

Return a Message instance to the global pool. You MUST NOT touch the Message after calling this function - it has effectively been freed.

[edit] public void sendToTarget()

Sends this Message to the Handler specified by target. Throws a null pointer exception if this field has not been set.

[edit] public void setData(HashMap data)

Sets a HashMap of arbitrary data values. Use arg1 and arg1 members as a lower cost way to send a few simple integer values, if you can.

[edit] public String toString()

Answers a string containing a concise, human-readable description of the receiver.

[edit] public void writeToParcel(Parcel dest)

[edit] References

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