將Google plus api集成到片段中時的ClassCastException

Question

我遵循developer.google.com中提到的所有步驟在我的應用程序中實現了googleplus api。

我將googleplus api集成到片段中，並且在運行代碼時出現ClassCastException異常。 我的片段類：在該行

import com.digiapes.apeonomy.animation.Positions; 
    import com.example.apeonomy.R; 
    import com.google.android.gms.common.ConnectionResult; 
    import com.google.android.gms.common.GooglePlayServicesUtil; 
    import com.google.android.gms.common.api.GoogleApiClient; 
    import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks; 
    import com.google.android.gms.plus.Plus; 
    import android.animation.ObjectAnimator; 
import android.app.Activity; 
import android.app.Fragment; 
import android.content.Intent; 
import android.content.IntentSender.SendIntentException; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.view.ViewGroup; 
import android.view.ViewTreeObserver.OnGlobalLayoutListener; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.ImageButton; 
import android.widget.Toast; 


    public class Login extends Fragment implements OnGlobalLayoutListener, 
      OnClickListener, GoogleApiClient.ConnectionCallbacks, 
      GoogleApiClient.OnConnectionFailedListener { 
     EditText UN, Pass; 
     View loginimage, loginusing, loginlayout; 
     ImageButton flogin, Glogin; 
     Button login1; 
     float f; 
     Positions pos = new Positions(); 
     String name = "Harsha"; 
     String pass = "hahaha"; 
     private static final int RC_SIGNIN = 0; 
     private static boolean mSignInClicked; 
     private GoogleApiClient mGoogleApiClient; 
     private boolean mIntentInProgress; 
     private boolean mSignedIn; 
     private ConnectionResult mConnectionResult; 
     private Activity c; 
     private boolean mSignedInClicked; 

     // Login_Register Lg=new Login_Register(); 
     @Override 
     public View onCreateView(LayoutInflater inflater, ViewGroup container, 
       Bundle savedInstanceState) { 
      View login = inflater.inflate(R.layout.login, container, false); 
      // TODO Auto-generated method stub 
      UN = (EditText) login.findViewById(R.id.UsernameL); 
      Pass = (EditText) login.findViewById(R.id.PassswordL); 
      loginimage = login.findViewById(R.id.LoginImage); 
      login1 = (Button) login.findViewById(R.id.Login); 
      loginusing = login.findViewById(R.id.loginusing); 
      loginlayout = login.findViewById(R.id.LoginLayout); 
      f = ((Login_Register) getActivity()).pos.getLIpos(); 
      loginimage.getViewTreeObserver().addOnGlobalLayoutListener(this); 
      UN.getBackground().setAlpha(50); 
      Pass.getBackground().setAlpha(50); 
      ObjectAnimator.ofFloat(loginusing, View.ALPHA, 0, 1).setDuration(1000) 
        .start(); 
      ObjectAnimator.ofFloat(loginlayout, View.ALPHA, 0, 1).setDuration(1000) 
        .start(); 
      login.findViewById(R.id.googlepluslog).setOnClickListener(this); 
      login.findViewById(R.id.facebooklog).setOnClickListener(this); 

      return login; 
     } 

     @Override 
     public void onGlobalLayout() { 
      pos.setLIpos(loginimage.getY()); 
      // TODO Auto-generated method stub 

     } 

     @Override 
     public void onActivityCreated(Bundle savedInstanceState) { 
      // TODO Auto-generated method stub 
      super.onActivityCreated(savedInstanceState); 
      ObjectAnimator 
        .ofFloat(loginimage, View.TRANSLATION_Y, 
          f - loginimage.getY() - 130, 0).setDuration(300) 
        .start(); 
      login1.setOnClickListener(this); 

     } 
     @Override 
     public void onCreate(Bundle savedInstanceState) { 
      // TODO Auto-generated method stub 
      super.onCreate(savedInstanceState); 
      mGoogleApiClient = new GoogleApiClient.Builder(getActivity()) 
      .addConnectionCallbacks((ConnectionCallbacks) getActivity().getApplicationContext()) 
      .addOnConnectionFailedListener(this).addApi(Plus.API, null) 
      .addScope(Plus.SCOPE_PLUS_LOGIN).build(); 

     } 

     @Override 
     public void onClick(View v) { 
      // TODO Auto-generated method stub 
      switch (v.getId()) { 
      case R.id.Login: 
       if (UN.getText().length() == 0 || Pass.getText().length() == 0) { 
        Toast.makeText(getActivity(), 
          "Please enter valid Username and Password", 
          Toast.LENGTH_SHORT).show(); 
       } else if (UN.getText().toString().equals(name) 
         && Pass.getText().toString().equals(pass)) { 

        Intent intent = new Intent(getActivity() 
          .getApplicationContext(), Main.class); 
        startActivity(intent); 
       } 
      break; 
     case R.id.facebooklog: 

      break; 
     case R.id.googlepluslog: 
      signInWithGplus(); 
      break; 

     } 

    } 

    @Override 
    public void onActivityResult(int requestCode, int resultCode, Intent data) { 
     // TODO Auto-generated method stub 
     if (requestCode == RC_SIGNIN) { 
      mIntentInProgress = false; 

      if (!mGoogleApiClient.isConnecting()) { 
       mGoogleApiClient.connect(); 
      } 
     } 
    } 
    private void signInWithGplus() { 
     // TODO Auto-generated method stub 
     if (!mGoogleApiClient.isConnecting()) { 
      mSignedIn = true; 
      resolveSignInerror(); 
     } 

    } 
    private void resolveSignInerror() { 
     // TODO Auto-generated method stub 
     if (mConnectionResult.hasResolution()) { 
      try { 
       mIntentInProgress = true; 
       mConnectionResult.startResolutionForResult(c, RC_SIGNIN); 
      } catch (SendIntentException e) { 
       mIntentInProgress = false; 
       mGoogleApiClient.connect(); 
      } 
     } 
    } 

    @Override 
    public void onConnectionFailed(ConnectionResult result) { 
     // TODO Auto-generated method stub 
     if (!result.hasResolution()) { 
      GooglePlayServicesUtil.getErrorDialog(result.getErrorCode(), c, 0) 
        .show(); 
      return; 
     } 
     if(!mIntentInProgress){ 
      mConnectionResult=result; 
      if(mSignedInClicked) 
       resolveSignInerror(); 
     } 
    } 

    @Override 
    public void onConnected(Bundle arg0) { 
     mSignedInClicked=false; 
     Toast.makeText(c, "Connected", Toast.LENGTH_SHORT).show(); 
     // TODO Auto-generated method stub 

    } 

    @Override 
    public void onConnectionSuspended(int arg0) { 
     // TODO Auto-generated method stub 
     mGoogleApiClient.connect(); 

    } 
    @Override 
    public void onStart() { 
     // TODO Auto-generated method stub 
     super.onStart(); 
     mGoogleApiClient.connect(); 
    } 
    @Override 
    public void onStop() { 
     // TODO Auto-generated method stub 
     super.onStop(); 
     if (mGoogleApiClient.isConnected()) { 
      mGoogleApiClient.disconnect(); 
     } 
    } 
} 

四處錯誤：

mGoogleApiClient = new GoogleApiClient.Builder(getActivity()) 
      .addConnectionCallbacks((ConnectionCallbacks) getActivity().getApplicationContext()) 
      .addOnConnectionFailedListener(this).addApi(Plus.API, null) 
      .addScope(Plus.SCOPE_PLUS_LOGIN).build(); 

的logcat：

在Error implementing GoogleApiClient Builder for Android development給出解決方案並沒有爲我的鍛鍊......

Answer 1

.addConnectionCallbacks((ConnectionCallbacks) getActivity().getApplicationContext()) 

這是錯誤的，該方法接受一個類執行GoogleApiClient.ConnectionCallbacks，請使用Fragment而不是getActivity().getApplicationContext()。