启用wifi且WifiManager.EXTRA_WIFI_STATE不可用时，android.net.wifi.STATE_CHANGE不广播

Question

表现：

<receiver android:name=".triggers.WifiTrigger">
        <intent-filter>
            <action android:name="android.net.wifi.STATE_CHANGE" />
        </intent-filter>
    </receiver>

权限：

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.CHANGE_WIFI_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.PROCESS_OUTGOING_CALLS" />

---

当WiFi禁用，连接或断开连接（未检查连接/禁用/启用）时执行接收器，但是启用WiFi时不会触发接收器，此外WifiManager.EXTRA_WIFI_STATE，在意图上还没有其他功能，我正在使用：

public class WifiTrigger extends BroadcastReceiver {
    ...
    @Override
public void onReceive(Context context, Intent intent) {
    SharedPreferences preferences= PreferenceManager.getDefaultSharedPreferences(context);

    int wifiState = intent.getIntExtra(WifiManager.EXTRA_WIFI_STATE, WifiManager.WIFI_STATE_UNKNOWN);
    int previousWifiState = intent.getIntExtra(WifiManager.EXTRA_PREVIOUS_WIFI_STATE, WifiManager.WIFI_STATE_UNKNOWN);
    log("p"+previousWifiState);
    log("c"+wifiState);
    //log is a defined method used for logging (it just calls Log.d(...,...)
    }
    ...
}

并保持记录p4 c4（WifiManager.WIFI_STATE_UNKNOWN为4）

---

Answer 1

您正在注册错误的Intent操作。您真正要寻找的是：

/**
 * Broadcast intent action indicating that Wi-Fi has been enabled, disabled,
 * enabling, disabling, or unknown. One extra provides this state as an int.
 * Another extra provides the previous state, if available.
 *
 * @see #EXTRA_WIFI_STATE
 * @see #EXTRA_PREVIOUS_WIFI_STATE
 */
@SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
public static final String WIFI_STATE_CHANGED_ACTION =
    "android.net.wifi.WIFI_STATE_CHANGED";

您要注册的操作是针对网络状态更改，而不是适配器状态更改：

/**
 * Broadcast intent action indicating that the state of Wi-Fi connectivity
 * has changed. One extra provides the new state
 * in the form of a {@link android.net.NetworkInfo} object. If the new
 * state is CONNECTED, additional extras may provide the BSSID and WifiInfo of
 * the access point.
 * as a {@code String}.
 * @see #EXTRA_NETWORK_INFO
 * @see #EXTRA_BSSID
 * @see #EXTRA_WIFI_INFO
 */
@SdkConstant(SdkConstantType.BROADCAST_INTENT_ACTION)
public static final String NETWORK_STATE_CHANGED_ACTION = 
    "android.net.wifi.STATE_CHANGE";

因此，只需从以下位置更改接收者注册：

<receiver android:name=".triggers.WifiTrigger">
    <intent-filter>
        <action android:name="android.net.wifi.STATE_CHANGE" />
    </intent-filter>
</receiver>

至

<receiver android:name=".triggers.WifiTrigger">
    <intent-filter>
        <action android:name="android.net.wifi.WIFI_STATE_CHANGED" />
    </intent-filter>
</receiver>

将解决您的问题。