249 lines
8.3 KiB
Java
249 lines
8.3 KiB
Java
|
/*
|
||
|
|
* Copyright (C) 2006 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 android.os;
|
||
|
|
|
||
|
|
import android.util.Config;
|
||
|
|
import android.util.Log;
|
||
|
|
import android.util.Printer;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Class used to run a message loop for a thread. Threads by default do
|
||
|
|
* not have a message loop associated with them; to create one, call
|
||
|
|
* {@link #prepare} in the thread that is to run the loop, and then
|
||
|
|
* {@link #loop} to have it process messages until the loop is stopped.
|
||
|
|
*
|
||
|
|
* <p>Most interaction with a message loop is through the
|
||
|
|
* {@link Handler} class.
|
||
|
|
*
|
||
|
|
* <p>This is a typical example of the implementation of a Looper thread,
|
||
|
|
* using the separation of {@link #prepare} and {@link #loop} to create an
|
||
|
|
* initial Handler to communicate with the Looper.
|
||
|
|
*
|
||
|
|
* <pre>
|
||
|
|
* class LooperThread extends Thread {
|
||
|
|
* public Handler mHandler;
|
||
|
|
*
|
||
|
|
* public void run() {
|
||
|
|
* Looper.prepare();
|
||
|
|
*
|
||
|
|
* mHandler = new Handler() {
|
||
|
|
* public void handleMessage(Message msg) {
|
||
|
|
* // process incoming messages here
|
||
|
|
* }
|
||
|
|
* };
|
||
|
|
*
|
||
|
|
* Looper.loop();
|
||
|
|
* }
|
||
|
|
* }</pre>
|
||
|
|
*/
|
||
|
|
public class Looper {
|
||
|
|
private static final boolean DEBUG = false;
|
||
|
|
private static final boolean localLOGV = DEBUG ? Config.LOGD : Config.LOGV;
|
||
|
|
|
||
|
|
// sThreadLocal.get() will return null unless you've called prepare().
|
||
|
|
private static final ThreadLocal sThreadLocal = new ThreadLocal();
|
||
|
|
|
||
|
|
final MessageQueue mQueue;
|
||
|
|
volatile boolean mRun;
|
||
|
|
Thread mThread;
|
||
|
|
private Printer mLogging = null;
|
||
|
|
private static Looper mMainLooper = null;
|
||
|
|
|
||
|
|
/** Initialize the current thread as a looper.
|
||
|
|
* This gives you a chance to create handlers that then reference
|
||
|
|
* this looper, before actually starting the loop. Be sure to call
|
||
|
|
* {@link #loop()} after calling this method, and end it by calling
|
||
|
|
* {@link #quit()}.
|
||
|
|
*/
|
||
|
|
public static final void prepare() {
|
||
|
|
if (sThreadLocal.get() != null) {
|
||
|
|
throw new RuntimeException("Only one Looper may be created per thread");
|
||
|
|
}
|
||
|
|
sThreadLocal.set(new Looper());
|
||
|
|
}
|
||
|
|
|
||
|
|
/** Initialize the current thread as a looper, marking it as an application's main
|
||
|
|
* looper. The main looper for your application is created by the Android environment,
|
||
|
|
* so you should never need to call this function yourself.
|
||
|
|
* {@link #prepare()}
|
||
|
|
*/
|
||
|
|
|
||
|
|
public static final void prepareMainLooper() {
|
||
|
|
prepare();
|
||
|
|
setMainLooper(myLooper());
|
||
|
|
if (Process.supportsProcesses()) {
|
||
|
|
myLooper().mQueue.mQuitAllowed = false;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
private synchronized static void setMainLooper(Looper looper) {
|
||
|
|
mMainLooper = looper;
|
||
|
|
}
|
||
|
|
|
||
|
|
/** Returns the application's main looper, which lives in the main thread of the application.
|
||
|
|
*/
|
||
|
|
public synchronized static final Looper getMainLooper() {
|
||
|
|
return mMainLooper;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Run the message queue in this thread. Be sure to call
|
||
|
|
* {@link #quit()} to end the loop.
|
||
|
|
*/
|
||
|
|
public static final void loop() {
|
||
|
|
Looper me = myLooper();
|
||
|
|
MessageQueue queue = me.mQueue;
|
||
|
|
|
||
|
|
// Make sure the identity of this thread is that of the local process,
|
||
|
|
// and keep track of what that identity token actually is.
|
||
|
|
Binder.clearCallingIdentity();
|
||
|
|
final long ident = Binder.clearCallingIdentity();
|
||
|
|
|
||
|
|
while (true) {
|
||
|
|
Message msg = queue.next(); // might block
|
||
|
|
//if (!me.mRun) {
|
||
|
|
// break;
|
||
|
|
//}
|
||
|
|
if (msg != null) {
|
||
|
|
if (msg.target == null) {
|
||
|
|
// No target is a magic identifier for the quit message.
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
if (me.mLogging!= null) me.mLogging.println(
|
||
|
|
">>>>> Dispatching to " + msg.target + " "
|
||
|
|
+ msg.callback + ": " + msg.what
|
||
|
|
);
|
||
|
|
msg.target.dispatchMessage(msg);
|
||
|
|
if (me.mLogging!= null) me.mLogging.println(
|
||
|
|
"<<<<< Finished to " + msg.target + " "
|
||
|
|
+ msg.callback);
|
||
|
|
|
||
|
|
// Make sure that during the course of dispatching the
|
||
|
|
// identity of the thread wasn't corrupted.
|
||
|
|
final long newIdent = Binder.clearCallingIdentity();
|
||
|
|
if (ident != newIdent) {
|
||
|
|
Log.wtf("Looper", "Thread identity changed from 0x"
|
||
|
|
+ Long.toHexString(ident) + " to 0x"
|
||
|
|
+ Long.toHexString(newIdent) + " while dispatching to "
|
||
|
|
+ msg.target.getClass().getName() + " "
|
||
|
|
+ msg.callback + " what=" + msg.what);
|
||
|
|
}
|
||
|
|
|
||
|
|
msg.recycle();
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Return the Looper object associated with the current thread. Returns
|
||
|
|
* null if the calling thread is not associated with a Looper.
|
||
|
|
*/
|
||
|
|
public static final Looper myLooper() {
|
||
|
|
return (Looper)sThreadLocal.get();
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Control logging of messages as they are processed by this Looper. If
|
||
|
|
* enabled, a log message will be written to <var>printer</var>
|
||
|
|
* at the beginning and ending of each message dispatch, identifying the
|
||
|
|
* target Handler and message contents.
|
||
|
|
*
|
||
|
|
* @param printer A Printer object that will receive log messages, or
|
||
|
|
* null to disable message logging.
|
||
|
|
*/
|
||
|
|
public void setMessageLogging(Printer printer) {
|
||
|
|
mLogging = printer;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Return the {@link MessageQueue} object associated with the current
|
||
|
|
* thread. This must be called from a thread running a Looper, or a
|
||
|
|
* NullPointerException will be thrown.
|
||
|
|
*/
|
||
|
|
public static final MessageQueue myQueue() {
|
||
|
|
return myLooper().mQueue;
|
||
|
|
}
|
||
|
|
|
||
|
|
private Looper() {
|
||
|
|
mQueue = new MessageQueue();
|
||
|
|
mRun = true;
|
||
|
|
mThread = Thread.currentThread();
|
||
|
|
}
|
||
|
|
|
||
|
|
public void quit() {
|
||
|
|
Message msg = Message.obtain();
|
||
|
|
// NOTE: By enqueueing directly into the message queue, the
|
||
|
|
// message is left with a null target. This is how we know it is
|
||
|
|
// a quit message.
|
||
|
|
mQueue.enqueueMessage(msg, 0);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Return the Thread associated with this Looper.
|
||
|
|
*/
|
||
|
|
public Thread getThread() {
|
||
|
|
return mThread;
|
||
|
|
}
|
||
|
|
|
||
|
|
/** @hide */
|
||
|
|
public MessageQueue getQueue() {
|
||
|
|
return mQueue;
|
||
|
|
}
|
||
|
|
|
||
|
|
public void dump(Printer pw, String prefix) {
|
||
|
|
pw.println(prefix + this);
|
||
|
|
pw.println(prefix + "mRun=" + mRun);
|
||
|
|
pw.println(prefix + "mThread=" + mThread);
|
||
|
|
pw.println(prefix + "mQueue=" + ((mQueue != null) ? mQueue : "(null"));
|
||
|
|
if (mQueue != null) {
|
||
|
|
synchronized (mQueue) {
|
||
|
|
long now = SystemClock.uptimeMillis();
|
||
|
|
Message msg = mQueue.mMessages;
|
||
|
|
int n = 0;
|
||
|
|
while (msg != null) {
|
||
|
|
pw.println(prefix + " Message " + n + ": " + msg.toString(now));
|
||
|
|
n++;
|
||
|
|
msg = msg.next;
|
||
|
|
}
|
||
|
|
pw.println(prefix + "(Total messages: " + n + ")");
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
public String toString() {
|
||
|
|
return "Looper{"
|
||
|
|
+ Integer.toHexString(System.identityHashCode(this))
|
||
|
|
+ "}";
|
||
|
|
}
|
||
|
|
|
||
|
|
static class HandlerException extends Exception {
|
||
|
|
|
||
|
|
HandlerException(Message message, Throwable cause) {
|
||
|
|
super(createMessage(cause), cause);
|
||
|
|
}
|
||
|
|
|
||
|
|
static String createMessage(Throwable cause) {
|
||
|
|
String causeMsg = cause.getMessage();
|
||
|
|
if (causeMsg == null) {
|
||
|
|
causeMsg = cause.toString();
|
||
|
|
}
|
||
|
|
return causeMsg;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|