问题
I am developing an Android Application that employs WiFi (Direct) for service discovery and P2P peer discovery/connection.
My development enviromment is as follows:-
Android Studio 3.0 Beta 4
Build #AI-171.4304935, built on August 29, 2017
JRE: 1.8.0_152-release-915-b01 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
Mac OS X 10.11.6
My Gradle build:-
apply plugin: 'com.android.application'
apply plugin: 'realm-android'
android {
compileSdkVersion 26
buildToolsVersion "26.0.1"
defaultConfig {
applicationId "com.research.wifi_direct"
minSdkVersion 19
targetSdkVersion 26
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_8
targetCompatibility JavaVersion.VERSION_1_8
}
}
buildTypes {
debug {
buildConfigField "String", "INSTANCE_NAME", "\"_vascodagama\""
buildConfigField "String", "SERVICE_TYPE", "\"_presence._tcp\""
}
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:26.0.2'
implementation 'com.android.support:recyclerview-v7:26.0.2'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
implementation 'com.yarolegovich:lovely-dialog:1.0.7'
implementation 'io.realm:android-adapters:2.1.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation('com.android.support.test.espresso:espresso-core:3.0.1', {
exclude group: 'com.android.support', module: 'support-annotations'
})
}
The devices I am testing on include:-
Nexus 7 - Android 6.0.1
Nexus 9 - Android 7.1.1
Samsung Tablet - Android 4.4.1
Pixel - Android 8.0.0
The service discovery works fine on all four devices.
However the P2P Peers List is always empty on the Pixel XL
running Android 8.0.0
.
The other three devices consistently discover each other as well as other miscellaneous devices
around my office e.g. such as a Samsung TV and my colleagues personal phones etc..
The only thing I can think of is that theres something about Android O
that inhibits P2P peers being discovered.
I cannot see anything in the "Whats New In Android O" to identify the culprit
Has anyone seen this behaviour on Android O
? What am I doing wrong? What am I missing?
The code I am basing my application on is to be found here
https://developer.android.com/training/connect-devices-wirelessly/wifi-direct.html https://developer.android.com/training/connect-devices-wirelessly/nsd-wifi-direct.html
Something odd that I noticed was that when I tried to keep the WiFi "stack" awake using an android.net.wifi.WifiManager.WifiLock
my application stopped working altogether. Further more I had to power off all my devices and restart them once I had removed the
associated WiFiLock code. And yes... I did add uses-permission android:name="android.permission.WAKE_LOCK"
.
UPDATE - 0001
Whats odd is that when I log out the extras available in my Broadcast Receiver for PEER_CHANGED I can see the available peers listed as shown here when the Android O Pixel XL has discovered my Nexus
WiFiDirectBroadcastRcvr: android.net.wifi.p2p.PEERS_CHANGED<<<<<EXTRA DATA :: ------------------------START
WiFiDirectBroadcastRcvr: EXTRA DATA :: wifiP2pDeviceList
Device: Nexus 7
deviceAddress: da:50:e6:7c:56:4e
primary type: 000A0050F2040005
secondary type: null
wps: 392
grpcapab: 0
devcapab: 37
status: 3
wfdInfo: WFD enabled: trueWFD DeviceInfo: 0
WFD CtrlPort: 0
WFD MaxThroughput: 0 (android.net.wifi.p2p.WifiP2pDeviceList)
WiFiDirectBroadcastRcvr: EXTRA DATA :: ------------------------FINISH
However when I then make my subsequent call to requestPeers I always receive an empty WifiP2pDeviceList
?
case WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION:
Log.d(TAG, "onReceive: WifiP2pManager.WIFI_P2P_PEERS_CHANGED_ACTION");
mWiFiPeer2PeerCommander.requestPeers(mWifiP2pManager, mWifiP2pManagerChannel);
break;
Am I supposed to use the WifiP2pDeviceList
from the passed Extra an not bother to call requestPeers
?
回答1:
I had the same problem. On my nexus 5x now also Android O. And I also always got an empty WifiP2pDeviceList. I think it's assign (?) with similar problem on Android 6 SCAN_RESULTS_AVAILABLE_ACTION return empty list in Android 6.0
It works for me...
回答2:
Set the targetSdkVersion <= 25 can solve this issue,but I don't know why.
回答3:
I faced the similar issue. I fixed it by adding
Step 1 : Add Location permission in manifest.
Step 2: Request permission dynamically in your activity.
Step 3: Now scan for WIFI peers. It will appear.
Kudos!!!
来源:https://stackoverflow.com/questions/46097660/android-o-issues-with-wifi-peer-discovery