Question

我正面临facebook android sdk 4的facebook登录按钮的奇怪问题。我按照指南转换我以前的代码（我使用旧的Facebook sdk），但android studio无法正确呈现按钮。这是我的登录按钮代码：

<com.facebook.login.widget.LoginButton
    xmlns:fb="http://schemas.android.com/apk/res-auto"
    android:id="@+id/fb_button"
    style="@style/FacebookLoginButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/my_button"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="-14dp"
    android:textSize="34sp"
    fb:login_text="@string/login_with_facebook"
    fb:logout_text="Logout" />

wbhere facebook登录按钮样式是

 <style name="FacebookLoginButton">
    <item name="android:background">@drawable/button_facebook</item>
    <item name="android:textColor">@color/white</item>
    <item name="android:textSize">21sp</item>
    <item name="android:gravity">center</item>

现在当我试图在android studio上看到预览时，我发现了这个错误：

java.lang.NoClassDefFoundError: Could not initialize class com.facebook.login.widget.LoginButton
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:408)
at org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:413)
at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:105)
at com.android.tools.idea.rendering.LayoutlibCallback.loadView(LayoutlibCallback.java:176)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:207)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:132)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:806)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:64)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:782)
at android.view.LayoutInflater.inflate(LayoutInflater.java:504)
at android.view.LayoutInflater.inflate(LayoutInflater.java:385)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:410)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:321)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:350)
at com.android.tools.idea.rendering.RenderService$5.compute(RenderService.java:708)
at com.android.tools.idea.rendering.RenderService$5.compute(RenderService.java:697)
at com.intellij.openapi.application.impl.ApplicationImpl.runReadAction(ApplicationImpl.java:932)
at com.android.tools.idea.rendering.RenderService.createRenderSession(RenderService.java:697)
at com.android.tools.idea.rendering.RenderService.render(RenderService.java:816)
at com.intellij.android.designer.designSurface.AndroidDesignerEditorPanel$6.run(AndroidDesignerEditorPanel.java:480)
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:320)
at com.intellij.util.ui.update.MergingUpdateQueue.execute(MergingUpdateQueue.java:310)
at com.intellij.util.ui.update.MergingUpdateQueue$2.run(MergingUpdateQueue.java:254)
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:269)
at com.intellij.util.ui.update.MergingUpdateQueue.flush(MergingUpdateQueue.java:227)
at com.intellij.util.ui.update.MergingUpdateQueue.run(MergingUpdateQueue.java:217)
at com.intellij.util.concurrency.QueueProcessor.runSafely(QueueProcessor.java:238)
at com.intellij.util.Alarm$Request$1.run(Alarm.java:327)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)

出了什么问题？

Answer 1

您需要覆盖片段中的onCreate，onCreateView和onViewCreated。

这样的事情：

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    FacebookSdk.sdkInitialize(getActivity().getApplicationContext());
    callbackManager = CallbackManager.Factory.create();
}

@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    loginButton = (LoginButton) view.findViewById(R.id.login_button);
    loginButton.setReadPermissions("email", "user_likes", "user_friends");
    loginButton.setFragment(this);
    setFacebookLoginText(loginButton);
    // Other app specific specialization

    // Callback registration
    loginButton.registerCallback(callbackManager, new FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(LoginResult loginResult) {
            Toast.makeText(getActivity(), "success", Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onCancel() {
            Toast.makeText(getActivity(), "fail", Toast.LENGTH_SHORT).show();
        }

        @Override
        public void onError(FacebookException exception) {
            Toast.makeText(getActivity(), "error", Toast.LENGTH_SHORT).show();
        }
    });

}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_facebook_login, container, false);
    return view;
}


@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    callbackManager.onActivityResult(requestCode, resultCode, data);
}

无法在android studio上呈现facebook登录按钮

1 个答案: