android - LocalBroadcastManager 类的 sendBroadcast 方法返回什么？

Question

LocalBroadcastManager.sendBroadcast() 的返回值( bool 值)没有记录。

我想当至少有一个接收者被注册时它返回 true，如果没有接收者被注册则返回 false。这是正确的吗？

关于此缺失文档存在未决问题:Issue 59626

Answer 1

是的，它会检查可用的接收器，如果没有找到则返回 false:

来自 method

219                ArrayList<ReceiverRecord> receivers = null;
220                for (int i=0; i<entries.size(); i++) {
221                    ReceiverRecord receiver = entries.get(i);
222                    if (debug) Log.v(TAG, "Matching against filter " + receiver.filter);
223
224                    if (receiver.broadcasting) {
225                        if (debug) {
226                            Log.v(TAG, "  Filter's target already added");
227                        }
228                        continue;
229                    }
230
231                    int match = receiver.filter.match(action, type, scheme, data,
232                            categories, "LocalBroadcastManager");
233                    if (match >= 0) {
234                        if (debug) Log.v(TAG, "  Filter matched!  match=0x" +
235                                Integer.toHexString(match));
236                        if (receivers == null) {
237                            receivers = new ArrayList<ReceiverRecord>();
238                        }
239                        receivers.add(receiver);
240                        receiver.broadcasting = true;
241                    } else {
242                        if (debug) {
243                            String reason;
244                            switch (match) {
245                                case IntentFilter.NO_MATCH_ACTION: reason = "action"; break;
246                                case IntentFilter.NO_MATCH_CATEGORY: reason = "category"; break;
247                                case IntentFilter.NO_MATCH_DATA: reason = "data"; break;
248                                case IntentFilter.NO_MATCH_TYPE: reason = "type"; break;
249                                default: reason = "unknown reason"; break;
250                            }
251                            Log.v(TAG, "  Filter did not match: " + reason);
252                        }
253                    }
254                }
255
256                if (receivers != null) {
257                    for (int i=0; i<receivers.size(); i++) {
258                        receivers.get(i).broadcasting = false;
259                    }
260                    mPendingBroadcasts.add(new BroadcastRecord(intent, receivers));
261                    if (!mHandler.hasMessages(MSG_EXEC_PENDING_BROADCASTS)) {
262                        mHandler.sendEmptyMessage(MSG_EXEC_PENDING_BROADCASTS);
263                    }
264                    return true;
265                }
266            }
267        }
268        return false;