Правильно ли я полагаю, что я не могу отправлять "липкие" трансляции с помощью LocalBroadcastManager? Если это так кажется очень близоруким, особенно если приложение использует фрагменты, которые можно поменять местами во время жизненного цикла приложения и использовать данные широковещания.
Использование LocalBroadcastManager для "липкой" трансляции
Ответ 1
Правильно ли я полагаю, что я не могу отправлять "липкие" трансляции с помощью LocalBroadcastManager?
Да, вы правы.
Если это так кажется очень близоруким, особенно если приложение использует фрагменты, которые можно поменять местами во время жизненного цикла приложения и использовать данные трансляции.
Вы можете взять исходный код LocalBroadcastManager и создать свои собственные липкие расширения, если вы этого желаете. Лично я хотел бы использовать другие способы хранения таких данных (фрагменты модели, одиночные или постоянные хранилища данных, в зависимости от сценария).
Ответ 2
Как сказал @CommonsWare, я попытался реализовать липкие исходные коды LocalBroadcastManager. Проверь это: https://gist.github.com/lidemin/5cd4080ebbc74154a0e7
Не уверен, что это лучший способ сделать это. Он работает до сих пор. Лично я предпочитаю использовать Отто.
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 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);
}
}
}
}
}