我认为我无法使用LocalBroadcastManager发送“粘性”广播，这是正确的吗？ 如果是这样，这似乎是非常短视的，特别是如果一个应用程序使用可以在应用程序生命周期中交换进出的碎片并依赖于广播数据..
答案 0 :(得分：13)
我是否认为我无法使用LocalBroadcastManager发送'粘性'广播？
是的，你是对的。
如果是这样，这似乎非常短视，特别是如果一个应用程序使用可以在应用程序生命周期中交换进出的碎片并依赖于广播数据..
如果您愿意，欢迎您将源代码带到LocalBroadcastManager并为其创建自己的粘性扩展。就个人而言，我会使用其他方式存储此类数据（模型片段，单例或持久数据存储，具体取决于方案）。
答案 1 :(得分：7)
正如@CommonsWare所说，我尝试使用LocalBroadcastManager源代码实现sticky。检查一下： https://gist.github.com/lidemin/5cd4080ebbc74154a0e7
不确定这是否是最好的方法。它现在运作良好。我个人更喜欢使用Otto。
public class StickyLocalBroadcastManager {
private static class ReceiverRecord {
final IntentFilter filter;
final BroadcastReceiver receiver;
boolean broadcasting;
ReceiverRecord(IntentFilter _filter, BroadcastReceiver _receiver) {
filter = _filter;
receiver = _receiver;
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder(128);
builder.append("Receiver{");
builder.append(receiver);
builder.append(" filter=");
builder.append(filter);
builder.append("}");
return builder.toString();
}
}
private static class BroadcastRecord {
final Intent intent;
final ArrayList<ReceiverRecord> receivers;
BroadcastRecord(Intent _intent, ArrayList<ReceiverRecord> _receivers) {
intent = _intent;
receivers = _receivers;
}
}
private static final String TAG = "LocalBroadcastManager";
private static final boolean DEBUG = false;
private final Context mAppContext;
private final HashMap<BroadcastReceiver, ArrayList<IntentFilter>> mReceivers
= new HashMap<BroadcastReceiver, ArrayList<IntentFilter>>();
private final HashMap<String, ArrayList<ReceiverRecord>> mActions
= new HashMap<String, ArrayList<ReceiverRecord>>();
private final ArrayList<BroadcastRecord> mPendingBroadcasts
= new ArrayList<BroadcastRecord>();
private final ArrayList<Intent> mStickyBroadcasts
= new ArrayList<Intent>();
static final int MSG_EXEC_PENDING_BROADCASTS = 1;
private final Handler mHandler;
private static final Object mLock = new Object();
private static StickyLocalBroadcastManager mInstance;
public static StickyLocalBroadcastManager getInstance(Context context) {
synchronized (mLock) {
if (mInstance == null) {
mInstance = new StickyLocalBroadcastManager(context.getApplicationContext());
}
return mInstance;
}
}
private StickyLocalBroadcastManager(Context context) {
mAppContext = context;
mHandler = new Handler(context.getMainLooper()) {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case MSG_EXEC_PENDING_BROADCASTS:
executePendingBroadcasts();
break;
default:
super.handleMessage(msg);
}
}
};
}
/**
* Register a receive for any local broadcasts that match the given IntentFilter.
*
* @param receiver The BroadcastReceiver to handle the broadcast.
* @param filter Selects the Intent broadcasts to be received.
* @see #unregisterReceiver
*/
public void registerReceiver(BroadcastReceiver receiver, IntentFilter filter) {
synchronized (mReceivers) {
ReceiverRecord entry = new ReceiverRecord(filter, receiver);
ArrayList<IntentFilter> filters = mReceivers.get(receiver);
if (filters == null) {
filters = new ArrayList<IntentFilter>(1);
mReceivers.put(receiver, filters);
}
filters.add(filter);
for (int i = 0; i < filter.countActions(); i++) {
String action = filter.getAction(i);
ArrayList<ReceiverRecord> entries = mActions.get(action);
if (entries == null) {
entries = new ArrayList<ReceiverRecord>(1);
mActions.put(action, entries);
}
entries.add(entry);
}
//check sticky broadcasts
for (Intent intent : mStickyBroadcasts) {
if (mActions.containsKey(intent.getAction())) {
sendBroadcast(intent, false);
}
}
}
}
/**
* Unregister a previously registered BroadcastReceiver. <em>All</em>
* filters that have been registered for this BroadcastReceiver will be
* removed.
*
* @param receiver The BroadcastReceiver to unregister.
* @see #registerReceiver
*/
public void unregisterReceiver(BroadcastReceiver receiver) {
synchronized (mReceivers) {
ArrayList<IntentFilter> filters = mReceivers.remove(receiver);
if (filters == null) {
return;
}
for (int i = 0; i < filters.size(); i++) {
IntentFilter filter = filters.get(i);
for (int j = 0; j < filter.countActions(); j++) {
String action = filter.getAction(j);
ArrayList<ReceiverRecord> receivers = mActions.get(action);
if (receivers != null) {
for (int k = 0; k < receivers.size(); k++) {
if (receivers.get(k).receiver == receiver) {
receivers.remove(k);
k--;
}
}
if (receivers.size() <= 0) {
mActions.remove(action);
}
}
}
}
}
}
/**
* remove the sticky broadcasts .
* @param action is the action need to be removed.
*/
public void removeStickyBroadcast(String action) {
if (action == null || action.length() <= 0) {
return;
}
synchronized (mStickyBroadcasts) {
Iterator<Intent> intentIterator = mStickyBroadcasts.iterator();
while (intentIterator.hasNext()) {
Intent intent = intentIterator.next();
if (action.equalsIgnoreCase(intent.getAction())) {
intentIterator.remove();
}
}
}
}
/**
* remove all the sticky broadcasts.
*/
public void removeAllStickyBroadcasts(){
synchronized (mStickyBroadcasts){
mStickyBroadcasts.clear();
}
}
/**
* send broadcast with specified action.
* @param action is the action .
* @return
*/
public boolean sendBroadcast(String action){
Intent intent = new Intent(action);
return sendBroadcast(intent);
}
/**
* send broadcast with specified action.
* @param action is the action .
* @return
*/
public boolean sendBroadcast(String action, boolean isSticky){
Intent intent = new Intent(action);
return sendBroadcast(intent, isSticky);
}
/**
* Broadcast the given intent to all interested BroadcastReceivers. This
* call is asynchronous; it returns immediately, and you will continue
* executing while the receivers are run.
*
* @param intent The Intent to broadcast; all receivers matching this
* Intent will receive the broadcast.
* @see #registerReceiver
*/
public boolean sendBroadcast(Intent intent) {
return sendBroadcast(intent, false);
}
/**
* Broadcast the given intent to all interested BroadcastReceivers. This
* call is asynchronous; it returns immediately, and you will continue
* executing while the receivers are run.
*
* @param intent The Intent to broadcast; all receivers matching this
* Intent will receive the broadcast.
* @param isSticky The flag of this intent is need to be sticky or not.
* @see #registerReceiver
*/
public boolean sendBroadcast(Intent intent, boolean isSticky) {
if (isSticky) {
mStickyBroadcasts.add(intent);
}
synchronized (mReceivers) {
final String action = intent.getAction();
final String type = intent.resolveTypeIfNeeded(
mAppContext.getContentResolver());
final Uri data = intent.getData();
final String scheme = intent.getScheme();
final Set<String> categories = intent.getCategories();
final boolean debug = DEBUG ||
((intent.getFlags() & Intent.FLAG_DEBUG_LOG_RESOLUTION) != 0);
if (debug) Log.v(
TAG, "Resolving type " + type + " scheme " + scheme
+ " of intent " + intent);
ArrayList<ReceiverRecord> entries = mActions.get(intent.getAction());
if (entries != null) {
if (debug) Log.v(TAG, "Action list: " + entries);
ArrayList<ReceiverRecord> receivers = null;
for (int i = 0; i < entries.size(); i++) {
ReceiverRecord receiver = entries.get(i);
if (debug) Log.v(TAG, "Matching against filter " + receiver.filter);
if (receiver.broadcasting) {
if (debug) {
Log.v(TAG, " Filter's target already added");
}
continue;
}
int match = receiver.filter.match(action, type, scheme, data,
categories, "LocalBroadcastManager");
if (match >= 0) {
if (debug) Log.v(TAG, " Filter matched! match=0x" +
Integer.toHexString(match));
if (receivers == null) {
receivers = new ArrayList<ReceiverRecord>();
}
receivers.add(receiver);
receiver.broadcasting = true;
} else {
if (debug) {
String reason;
switch (match) {
case IntentFilter.NO_MATCH_ACTION:
reason = "action";
break;
case IntentFilter.NO_MATCH_CATEGORY:
reason = "category";
break;
case IntentFilter.NO_MATCH_DATA:
reason = "data";
break;
case IntentFilter.NO_MATCH_TYPE:
reason = "type";
break;
default:
reason = "unknown reason";
break;
}
Log.v(TAG, " Filter did not match: " + reason);
}
}
}
if (receivers != null) {
for (int i = 0; i < receivers.size(); i++) {
receivers.get(i).broadcasting = false;
}
mPendingBroadcasts.add(new BroadcastRecord(intent, receivers));
if (!mHandler.hasMessages(MSG_EXEC_PENDING_BROADCASTS)) {
mHandler.sendEmptyMessage(MSG_EXEC_PENDING_BROADCASTS);
}
return true;
}
}
}
return false;
}
/**
* Like {@link #sendBroadcast(Intent, boolean)}, but if there are any receivers for
* the Intent this function will block and immediately dispatch them before
* returning.
*/
public void sendBroadcastSync(Intent intent) {
if (sendBroadcast(intent, false)) {
executePendingBroadcasts();
}
}
private void executePendingBroadcasts() {
while (true) {
BroadcastRecord[] brs = null;
synchronized (mReceivers) {
final int N = mPendingBroadcasts.size();
if (N <= 0) {
return;
}
brs = new BroadcastRecord[N];
mPendingBroadcasts.toArray(brs);
mPendingBroadcasts.clear();
}
for (int i = 0; i < brs.length; i++) {
BroadcastRecord br = brs[i];
for (int j = 0; j < br.receivers.size(); j++) {
br.receivers.get(j).receiver.onReceive(mAppContext, br.intent);
}
}
}
}
}