我正在使用本指南 https://developers.facebook.com/docs/android/getting-started . 我在 Facebook 的开发者页面上创建了应用程序，并在开发者设置中添加了包名、哈希键。

但是我收到了这个错误: Caused by: java.lang.NullPointerException: 参数 'applicationId' 不能为空

主要 Activity :

public class MainActivity extends ActionBarActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();
        }


        Session session = new Session.Builder(this).setApplicationId("597651723652854").build();

        session.openActiveSession(this, true, new Session.StatusCallback() {

              // callback when session changes state
              @Override
              public void call(Session session, SessionState state, Exception exception) {
                if (session.isOpened()) {

                  // make request to the /me API
                  Request.executeMeRequestAsync(session, new Request.GraphUserCallback() {

                    // callback after Graph API response with user object
                    @Override
                    public void onCompleted(GraphUser user, Response response) {
                      if (user != null) {
                        TextView welcome = (TextView) findViewById(R.id.welcome);
                        welcome.setText("Hello " + user.getName() + "!");
                      }
                    }
                  });
                }
              }
            });

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

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

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


}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.fuckufb"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="18" />
    <uses-permission android:name="android.permission.INTERNET"/>

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <meta-data android:name="com.facebook.sdk.ApplicationId" android:resource="@string/app_id"/>
        <activity
            android:name="com.example.fuckufb.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>        
        <activity android:name="com.facebook.LoginActivity"></activity>
    </application>

</manifest>

字符串.xml:

<string name="app_id">597651723652854</string>

最佳答案

你可以把它放在 manifest.xml 上

<meta-data android:name="com.facebook.sdk.ApplicationId" android:value="@string/app_id"/>

关于android - Facebook SDK 错误 :Argument 'applicationId' cannot be null，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/22516313/