您好我正在将Google登录集成到我的应用中。最近，由于某些原因，Android Studio无法识别Plus_Login范围（应用程序访问基本配置文件信息等所必需的），这是我唯一关心的问题。我目前的错误是
Error:(40, 17) error: method addScope in class Builder cannot be applied to given types;
required: Scope
found: String
reason: actual argument String cannot be converted to Scope by method invocation conversion
这是我的onCreate文件，其中找到了错误
编辑1 - 添加了导入语句和变量声明
package com.instigate.aggregator06;
import android.content.Intent;
import android.content.IntentSender;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks;
import com.google.android.gms.common.api.GoogleApiClient.OnConnectionFailedListener;
import com.google.android.gms.common.Scopes;
import com.google.android.gms.common.api.Scope;
import com.google.android.gms.plus.Plus;
public class SocialNetworkActivity extends AppCompatActivity implements
ConnectionCallbacks, OnConnectionFailedListener, View.OnClickListener {
private static final String TAG = "Social Network Activity";
/* Request code used to invoke sign in user interactions. */
private static final int RC_SIGN_IN = 0;
/* Client used to interact with Google APIs. */
private GoogleApiClient mGoogleApiClient;
/* A flag indicating that a PendingIntent is in progress and prevents
* us from starting further intents.
*/
private boolean mIntentInProgress;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(Plus.API)
.addScope(Scopes.PLUS_LOGIN) // <----- This is where the error is found
.addScope(Scopes.PLUS_ME)
.build();
findViewById(R.id.sign_in_button).setOnClickListener(this);
}
我已经搜索了一段时间来找到这个错误的解决方案（因为Plus_Login范围应该正常运行）但是找不到解决方案。
编辑2 - 解决后的错误 我找到了答案。显然不是：
.addScope(Scopes.PLUS_LOGIN)
.addScope(Scopes.PLUS_ME)
我们写这个
.addScope(new Scope(Scopes.PLUS_LOGIN))
.addScope(new Scope(Scopes.PLUS_ME))
解决了我的问题。
然而，它揭示了一个新问题：
findViewById(R.id.sign_in_button).setOnClickListener(this);
其中logcat指出此时存在NullPointerException。
编辑3 - 解决了NullPointerException 我已经解决了NullPointer异常问题，但我的Google+登录按钮仍无法正常运行。
这是整体课程（上面提到的代码段的延续）
package com.instigate.aggregator06;
import android.content.Intent;
import android.content.IntentSender;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks;
import com.google.android.gms.common.api.GoogleApiClient.OnConnectionFailedListener;
import com.google.android.gms.common.Scopes;
import com.google.android.gms.common.api.Scope;
import com.google.android.gms.plus.Plus;
public class SocialNetworkActivity extends AppCompatActivity implements
ConnectionCallbacks, OnConnectionFailedListener, View.OnClickListener {
private static final String TAG = "Social Network Activity";
/* Request code used to invoke sign in user interactions. */
private static final int RC_SIGN_IN = 0;
/* Client used to interact with Google APIs. */
private GoogleApiClient mGoogleApiClient;
/* A flag indicating that a PendingIntent is in progress and prevents
* us from starting further intents.
*/
private boolean mIntentInProgress;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_social_network);
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(Plus.API)
//.addScope(Scopes.PLUS_LOGIN)
//.addScope(Scopes.PLUS_ME)
.addScope(new Scope(Scopes.PLUS_ME))
.addScope(new Scope(Scopes.PLUS_LOGIN))
.build();
this.findViewById(R.id.sign_in_button).setOnClickListener(this);
}
protected void onStart() {
super.onStart();
mGoogleApiClient.connect();
}
protected void onStop() {
super.onStop();
if (mGoogleApiClient.isConnected()) {
mGoogleApiClient.disconnect();
}
}
/* Code in case second one doesn't work
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
// Could not connect to Google Play Services. The user needs to select an account,
// grant permissions or resolve an error in order to sign in. Refer to the javadoc for
// ConnectionResult to see possible error codes.
Log.d(TAG, "onConnectionFailed:" + connectionResult);
if (!mIsResolving && mShouldResolve) {
if (connectionResult.hasResolution()) {
try {
connectionResult.startResolutionForResult(this, RC_SIGN_IN);
mIsResolving = true;
} catch (IntentSender.SendIntentException e) {
Log.e(TAG, "Could not resolve ConnectionResult.", e);
mIsResolving = false;
mGoogleApiClient.connect();
}
} else {
// Could not resolve the connection result, show the user an
// error dialog.
showErrorDialog(connectionResult);
}
}
}*/
public void onConnectionFailed(ConnectionResult result) {
if (!mIntentInProgress && result.hasResolution()) {
try {
mIntentInProgress = true;
startIntentSenderForResult(result.getResolution().getIntentSender(),
RC_SIGN_IN, null, 0, 0, 0);
} catch (IntentSender.SendIntentException e) {
// The intent was canceled before it was sent. Return to the default
// state and attempt to connect to get an updated ConnectionResult.
mIntentInProgress = false;
mGoogleApiClient.connect();
}
}
}
public void onConnected(Bundle connectionHint) {
// We've resolved any connection errors. mGoogleApiClient can be used to
// access Google APIs on behalf of the user.
Log.d(TAG, "onConnected:" + connectionHint);
Intent j = new Intent(SocialNetworkActivity.this, AccountPageActivity.class);
startActivity(j);
}
protected void onActivityResult(int requestCode, int responseCode, Intent intent) {
if (requestCode == RC_SIGN_IN) {
mIntentInProgress = false;
if (!mGoogleApiClient.isConnecting()) {
mGoogleApiClient.connect();
}
}
}
public void onConnectionSuspended(int cause) {
mGoogleApiClient.connect();
}
@Override
public void onClick(View v) {
if (v.getId() == R.id.sign_in_button) {
//onSignInClicked();
mGoogleApiClient.connect();
}
// ...
}
/* I find this unnecesary
private void onSignInClicked() {
// User clicked the sign-in button, so begin the sign-in process and automatically
// attempt to resolve any errors that occur.
//mShouldResolve = true;
mGoogleApiClient.connect();
// Show a message to the user that we are signing in.
//mStatusTextView.setText(R.string.signing_in);
}*/
public void backToMainPage(View view) {
Intent j = new Intent(SocialNetworkActivity.this, MainActivity.class);
startActivity(j);
}
}
这是我的该类文件的xml
<RelativeLayout 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:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingBottom="@dimen/activity_vertical_margin"
tools:context="com.instigate.aggregator06.SelectSNActivity"
android:orientation="vertical"
android:id="@+id/SelectSNActivity"
android:weightSum="1">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/backbtn2"
android:id="@+id/backbtntest"
android:layout_gravity="right"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_marginBottom="43dp"
android:onClick="backToMainPage"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="@string/selectSocialNetwork"
android:id="@+id/selectSocialNetworkHeader"
android:textStyle="bold"
android:textSize="36sp"
android:layout_gravity="center_horizontal"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
<com.google.android.gms.common.SignInButton
android:id="@+id/sign_in_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/selectSocialNetworkHeader"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginTop="52dp" />
</RelativeLayout>
非常感谢任何帮助，谢谢。
答案 0 :(得分：1)
你有
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
您缺少setContentView(R.layout.activity_main)
您的布局必须
<com.google.android.gms.common.SignInButton
android:id="@+id/sign_in_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
另外，请检查xml中按钮的ID，并确保在活动中引用相同的内容