Java Can'；无法从花名册中获取用户（Smack）

我使用

Smack

和

xmpp

发送消息，我在服务器

OpenFire

中创建了两个用户，创建了群朋友，并在群中添加了两个用户

现在我想从我手机上的花名册中获取用户，我使用这样的代码：

Roster roster = Roster.getInstanceFor(connection);
Collection<RosterEntry> entries = roster.getEntries();
Presence presence;
for (RosterEntry entry : entries) {
    presence = roster.getPresence(entry.getUser());
    Log.e("Users in roster ", entry.getUser());
    Log.e("Name of user in roster ", presence.getType().name());
    Log.e("Status in roster", presence.getStatus());
}

---

pest your build.gradle（Module:app）Openfire组不是花名册组，它们是Openfire的自定义功能。@Radhey刚刚添加了它。@MrPk在这种情况下如何创建花名册？如果（！花名册.isLoaded（））请尝试{花名册.reloadAndWait（）；}catch（SmakException.NotLoggeDineException | SmakException.NotConnectedException | InterruptedException e）{e.printStackTrace（）；}，在for循环之前的语句。@Lucky_

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.0"
    defaultConfig {
        applicationId "com.example.iryna.smack"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.0.1'
    compile 'com.android.support:appcompat-v7:25.0.1'
    compile 'org.igniterealtime.smack:smack-android:4.1.4'
// Optional for XMPPTCPConnection
    compile 'org.igniterealtime.smack:smack-tcp:4.1.4'
// Optional for XMPP-IM (RFC 6121) support (Roster, Threaded Chats)
    compile 'org.igniterealtime.smack:smack-im:4.1.4'
// Optional for XMPP extensions support
    compile 'org.igniterealtime.smack:smack-extensions:4.1.4'
    testCompile 'junit:junit:4.12'
}