我正在尝试不使用登录按钮登录。 我跟着facebook教程，但我不能让它工作，总是给我NullPointerException。 我的清单：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.hema.testfcaebooksdk" >
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<meta-data android:name="com.facebook.sdk.ApplicationId" android:value="@string/facebook_app_id"/>
<activity android:name="com.facebook.FacebookActivity"
android:configChanges=
"keyboard|keyboardHidden|screenLayout|screenSize|orientation"
android:theme="@android:style/Theme.Translucent.NoTitleBar"
android:label="@string/app_name" />
<provider android:authorities="com.facebook.app.FacebookContentProvider****************"
android:name="com.facebook.FacebookContentProvider"
android:exported="true" />
<activity
android:name=".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>
</application>
</manifest>
我用它来登录facebook的活动：
public class MainActivity extends ActionBarActivity {
CallbackManager callbackManager;
LoginManager loginManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FacebookSdk.sdkInitialize(getApplicationContext());
callbackManager = CallbackManager.Factory.create();
loginManager = LoginManager.getInstance();
loginManager.registerCallback(callbackManager,
new FacebookCallback<LoginResult>() {
@Override
public void onSuccess(LoginResult loginResult) {
// App code
Toast.makeText(getApplicationContext(), loginResult.getAccessToken().toString(), Toast.LENGTH_SHORT).show();
}
@Override
public void onCancel() {
// App code
}
@Override
public void onError(FacebookException exception) {
// App code
}
});
Collection<String> permissions = Arrays.asList("public_profile", "user_friends");
loginManager.logInWithReadPermissions(this, permissions); // Null Pointer Exception here
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
callbackManager.onActivityResult(requestCode, resultCode, data);
}
}
我的日志猫：
04-14 20:03:46.840 8075-8075/com.example.hema.testfacebooksdk E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.hema.testfacebooksdk, PID: 8075
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.hema.testfacebooksdk/com.example.hema.testfacebooksdk.MainActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2413)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2471)
at android.app.ActivityThread.access$900(ActivityThread.java:175)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5602)
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:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.facebook.login.LoginManager.getLogger(LoginManager.java:391)
at com.facebook.login.LoginManager.logCompleteLogin(LoginManager.java:414)
at com.facebook.login.LoginManager.startLogin(LoginManager.java:384)
at com.facebook.login.LoginManager.logInWithReadPermissions(LoginManager.java:262)
at com.example.hema.testfacebooksdk.MainActivity.onCreate(MainActivity.java:59)
at android.app.Activity.performCreate(Activity.java:5451)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1093)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2377)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2471)
at android.app.ActivityThread.access$900(ActivityThread.java:175)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1308)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:146)
at android.app.ActivityThread.main(ActivityThread.java:5602)
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:1283)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
at dalvik.system.NativeStart.main(Native Method)
我尝试了所有的东西，但结果是 NullPointerException 请帮帮我！
答案 0 :(得分：21)
好的，我不知道你是否已经解决了问题，但这就是我解决问题的方法
List<String> permissionNeeds= Arrays.asList("user_photos", "friends_photos", "email", "user_birthday", "user_friends");
super.onCreate(savedInstanceState);
FacebookSdk.sdkInitialize(getApplicationContext());
mCallbackManager = CallbackManager.Factory.create();
LoginManager.getInstance().logInWithReadPermissions(
this,
permissionNeeds);
LoginManager.getInstance().registerCallback(mCallbackManager,
new FacebookCallback<LoginResult>() {
@Override
public void onSuccess(LoginResult loginResults) {
GraphRequest request = GraphRequest.newMeRequest(
loginResults.getAccessToken(),
new GraphRequest.GraphJSONObjectCallback() {
@Override
public void onCompleted(
JSONObject object,
GraphResponse response) {
// Application code
Log.v("LoginActivity", response.toString());
}
});
Bundle parameters = new Bundle();
parameters.putString("fields", "id,name,email,gender, birthday");
request.setParameters(parameters);
request.executeAsync();
}
@Override
public void onCancel() {
Log.e("dd","facebook login canceled");
}
@Override
public void onError(FacebookException e) {
Log.e("dd", "facebook login failed error");
}
});
答案 1 :(得分：6)
尝试在应用程序节点而不是第一个活动节点下移动元数据和活动。
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<meta-data android:name="com.facebook.sdk.ApplicationId" android:value="@string/facebook_app_id"/>
<activity
android:name=".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.FacebookActivity" />
</application>
答案 2 :(得分：5)
您的问题是您在FacebookSdk.sdkInitialize(getApplicationContext());之后使用setContentView(R.layout.activity_main);。您应该在之前使用 setContentView()。可以找到带有示例代码的完整 facebook登录示例 here。
答案 3 :(得分：4)
尝试这种方式：
在Facebook开发者上创建Android应用并将其设置为公开而非开发模式。
清单：
<meta-data android:name="com.facebook.sdk.ApplicationId" android:value="@string/facebook_app_id"/>
<activity
android:name="com.facebook.FacebookActivity"
android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
android:label="@string/app_name"/>
的strings.xml
XXXXXXXXXXXXXX
如果你想使用片段登录，正确的方法是：
第1步：
CallbackManager mCallbackManager;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//@Deprecated for latest version, without this line working fine.
//FacebookSdk.sdkInitialize(getActivity().getApplicationContext());
mCallbackManager = CallbackManager.Factory.create();
LoginManager.getInstance().registerCallback(mCallbackManager,
new FacebookCallback<LoginResult>() {
@Override
public void onSuccess(LoginResult loginResult) {
// App code
Log.e("Success", "Login");
Bundle parameters = new Bundle();
parameters.putString("fields", "id, first_name, last_name ,email, gender, birthday");
GraphRequest gr = GraphRequest.newMeRequest(
loginResult.getAccessToken(), new GraphRequest.GraphJSONObjectCallback() {
@Override
public void onCompleted(JSONObject json, GraphResponse response) {
if (response.getError() != null) {
// handle error
System.out.println("ERROR "+response.getError().toString());
} else {
//System.out.println("Success");
try {
String jsonresult = String.valueOf(json);
System.out.println("JSON Result"+jsonresult);
String resp = String.valueOf(response.getJSONObject());
System.out.println("JSON resp "+resp);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
});
gr.setParameters(parameters);
gr.executeAsync();
}
@Override
public void onCancel() {
// App code
Log.e("onCancel", "Login");
}
@Override
public void onError(FacebookException onError) {
// App code
Log.e("onError", "Login "+onError.getMessage());
}
});
}
第2步：
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
mCallbackManager.onActivityResult(requestCode, resultCode, data);
}
}
第3步： - 在OnClickListener中
LoginManager.getInstance().logInWithReadPermissions(YourFragment.this, Arrays.asList("public_profile"));
我正在使用getActivity()因此，每当有人闪烁而不是显示Facebook登录视图时。基本上，getActivity()必须使用FragmentClaseName.this。我希望这会对你有所帮助。快乐的编码!!!
答案 4 :(得分：3)
也许你忘了在AndroidManifest.xml中添加这个代码
<activity
android:name="com.facebook.FacebookActivity"
android:configChanges="keyboard|keyboardHidden|screenLayout|screenSize|orientation"
android:label="@string/app_name"
android:theme="@android:style/Theme.Translucent.NoTitleBar" />
<meta-data
android:name="com.facebook.sdk.ApplicationId"
android:value="@string/facebook_app_id" />
答案 5 :(得分：0)
1）你应该在setContentView（）
之前初始化sdk2）你应该在某个按钮点击监听器上写Loginmanager.getInstance（）。logInWithReadPermission（.....）