未找到Android Facebook LoginButton类

Question

我将Facebook SDK(v3.21.1)模块导入Android Studio(v1.0.2),并尝试按照文档中的com.facebook.widget.LoginButton建议使用以下代码创建LoginActivity :

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <com.facebook.widget.LoginButton
        android:id="@+id/authButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:layout_marginTop="30dp"
        />

</LinearLayout>

但是,Android Studio中的渲染器表示无法找到LoginButton类:

The following classes could not be found: - com.facebook.widget.LoginButton

我知道该类存在是因为我可以打开该文件,并且它位于正确的位置:

我知道它存在,但为了向Android Studio证明它确实存在,我尝试按照渲染器中的建议创建一个类,并收到以下错误:

我也尝试了以下内容:

• 重新导入Facebook SDK(删除/重新导入Facebook模块:删除物理文件等)
• 重新打开我的项目
• 重新打开Android Studio
• 建立项目

什么都行不通.有点荒谬的是,即使是自动完成也可以看到这个类:

编辑:我尝试在模拟器中运行应用程序,忽略渲染错误,应用程序崩溃并出现以下错误:

12-31 03:47:15.593    2824-2824/com.test.playground E/AndroidRuntime? FATAL EXCEPTION: main
    Process: com.test.playground, PID: 2824
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test.playground/com.test.playground.LoginActivity}: android.view.InflateException: Binary XML file line #7: Error inflating class com.facebook.widget.LoginButton
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: android.view.InflateException: Binary XML file line #7: Error inflating class com.facebook.widget.LoginButton
            at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:707)
            at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
            at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:290)
            at android.app.Activity.setContentView(Activity.java:1929)
            at com.test.playground.LoginActivity.onCreate(LoginActivity.java:15)
            at android.app.Activity.performCreate(Activity.java:5231)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.ClassNotFoundException: Didn't find class "com.facebook.widget.LoginButton" on path: DexPathList[[zip file "/data/app/com.test.playground-2.apk"],nativeLibraryDirectories=[/data/app-lib/com.test.playground-2, /system/lib]]
            at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
            at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
            at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
            at android.view.LayoutInflater.createView(LayoutInflater.java:559)
            at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:696)
            at android.view.LayoutInflater.rInflate(LayoutInflater.java:755)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:492)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:397)
            at android.view.LayoutInflater.inflate(LayoutInflater.java:353)
            at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:290)
            at android.app.Activity.setContentView(Activity.java:1929)
            at com.test.playground.LoginActivity.onCreate(LoginActivity.java:15)
            at android.app.Activity.performCreate(Activity.java:5231)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2148)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)

同样,该类确实存在,似乎Android Studio无法找到它.该类可以在项目目录下查看com.faceook.widget.LoginButton...我不知道我错过了什么.我一直试图弄清楚这几个小时,没有任何工作.

Answer 1

对于那些谁仍然有问题,改com.facebook.widget.LoginButton到com.facebook.login.widget.LoginButton可能的帮助.

Answer 2

您是否已将Facebook SDK集成到项目中？检查build.gradle您的模块,确保Facebook SDK是依赖项.如果没有,请添加它并与Gradle同步,然后重试.

应该将Facebook模块添加到build.gradle使用它的项目的依赖项中:

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile project(':facebook')
}

同样,Facebook模块应该导入settings.gradle:

include ':app', ':facebook'