我有一个自定义类来检查网络连接，如果没有连接则显示对话框。但是，无论什么时候没有连接它都会在alertDialog.show();上崩溃。不确定我在哪里出错了。
以下是自定义类。
package com.garciaericn.goodeats.helpers;
import android.app.AlertDialog;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.provider.Settings;
public class CheckConnection {
Context mContext;
ConnectivityManager connectivityManager;
public CheckConnection(Context context) {
mContext = context;
connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
}
public boolean isConnected() {
NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected()) {
// Return true if connected
return true;
} else {
// Display dialog for user to connect, with intent to wifi settings
showConnectionFailedDialog();
}
// Return false by default
return false;
}
private void showConnectionFailedDialog() {
// Display dialog for user to connect, with intent to wifi settings
AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(mContext)
.setTitle("No Network Connection")
.setMessage("Please enable wifi data from.");
alertDialogBuilder.setPositiveButton("Wifi Settings", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Intent mobileSettingsIntent = new Intent(Settings.ACTION_WIRELESS_SETTINGS);
mContext.startActivity(mobileSettingsIntent);
dialog.dismiss();
}
});
alertDialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
alertDialogBuilder.setNeutralButton("Mobile Network", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Intent mobileSettingsIntent = new Intent(Settings.ACTION_WIRELESS_SETTINGS);
mContext.startActivity(mobileSettingsIntent);
dialog.dismiss();
}
});
AlertDialog alertDialog = alertDialogBuilder.create();
alertDialog.show();
}
}
我得到的错误堆栈是：
11-22 17:29:15.895 19326-19326/com.garciaericn.goodeats E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.garciaericn.goodeats, PID: 19326
android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application
at android.view.ViewRootImpl.setView(ViewRootImpl.java:566)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:272)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
at android.app.Dialog.show(Dialog.java:298)
at com.garciaericn.goodeats.helpers.CheckConnection.showConnectionFailedDialog(CheckConnection.java:76)
at com.garciaericn.goodeats.helpers.CheckConnection.isConnected(CheckConnection.java:35)
at com.garciaericn.goodeats.login.LoginFragment.onConnectionFailed(LoginFragment.java:185)
at com.google.android.gms.common.internal.e.b(Unknown Source)
at com.google.android.gms.common.api.b.gn(Unknown Source)
at com.google.android.gms.common.api.b.d(Unknown Source)
at com.google.android.gms.common.api.b$4.onConnectionFailed(Unknown Source)
at com.google.android.gms.common.internal.e.b(Unknown Source)
at com.google.android.gms.common.internal.d$h.b(Unknown Source)
at com.google.android.gms.common.internal.d$h.g(Unknown Source)
at com.google.android.gms.common.internal.d$b.gU(Unknown Source)
at com.google.android.gms.common.internal.d$a.handleMessage(Unknown Source)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
来自：
package com.garciaericn.goodeats.login;
import android.app.Activity;
import android.app.Fragment;
import android.content.Intent;
import android.content.IntentSender;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import com.garciaericn.goodeats.R;
import com.garciaericn.goodeats.helpers.CheckConnection;
import com.garciaericn.goodeats.main.FavoritesActivity;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.SignInButton;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.plus.Plus;
public class LoginFragment extends Fragment implements View.OnClickListener, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener{
public static final String TAG = "com.garciaericn.goodeats.login.LoginFragment.TAG";
/* Request code used to invoke sign in user interactions. */
private static final int RC_SIGN_IN = 0;
private static final int RC_LOGGED_IN = 1034553;
public static final int RC_SIGN_OUT = 34458392;
/* 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;
/* Store the connection result from onConnectionFailed callbacks so that we can
* resolve them when the user clicks sign-in.
*/
private ConnectionResult mConnectionResult;
private boolean mSignInClicked;
private boolean mSignedIn;
private CheckConnection checkConnection;
public LoginFragment() {
}
public static LoginFragment getInstance() {
return new LoginFragment();
}
private void signOut() {
if (mGoogleApiClient.isConnected()){
Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
mGoogleApiClient.disconnect();
mGoogleApiClient.connect();
mIntentInProgress = false;
mSignInClicked = false;
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// checkConnection = new CheckConnection(getActivity().getApplicationContext());
setHasOptionsMenu(true);
mGoogleApiClient = new GoogleApiClient.Builder(getActivity())
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(Plus.API)
.addScope(Plus.SCOPE_PLUS_LOGIN)
.build();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_login, container, false);
checkConnection = new CheckConnection(getActivity().getApplicationContext());
SignInButton signInButton = (SignInButton) view.findViewById(R.id.g_plus_login);
signInButton.setSize(SignInButton.SIZE_WIDE);
signInButton.setOnClickListener(this);
return view;
}
@Override
public void onStart() {
super.onStart();
mGoogleApiClient.connect();
}
@Override
public void onStop() {
super.onStop();
if (mGoogleApiClient.isConnected()) {
mGoogleApiClient.disconnect();
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_sign_out:
if (mGoogleApiClient.isConnected()) {
Plus.AccountApi.clearDefaultAccount(mGoogleApiClient);
mGoogleApiClient.disconnect();
mGoogleApiClient.connect();
}
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onClick(View v) {
checkConnection.isConnected();
switch (v.getId()) {
case R.id.g_plus_login:
if (!mGoogleApiClient.isConnected()) {
mSignInClicked = true;
resolveSignInError();
}
break;
default:
// If default action is needed.
break;
}
}
@Override
public void onConnected(Bundle bundle) {
mSignInClicked = false;
mSignedIn = true;
// User is connected
String accountName = Plus.AccountApi.getAccountName(mGoogleApiClient);
Toast.makeText(getActivity(), accountName, Toast.LENGTH_SHORT).show();
// String accountID = GoogleAuthUtil.getAccountId(getActivity(), accountName);
// try {
// accountID = GoogleAuthUtil.getAccountId(getActivity().getApplicationContext(),accountName);
// } catch (GoogleAuthException e) {
// e.printStackTrace();
// } catch (IOException e) {
// e.printStackTrace();
// }
// if (accountID != null) {
// // TODO: createLocalAccount() = Store account name and id with DB of restaurants
// }
// Launch main activity
Intent intent = new Intent(getActivity(), FavoritesActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
@Override
public void onConnectionSuspended(int i) {
mGoogleApiClient.connect();
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
if (!mIntentInProgress) {
// Store the ConnectionResult so that we can use it later when the user clicks
// 'sign-in'.
mConnectionResult = connectionResult;
if (mSignInClicked) {
resolveSignInError();
}
}
checkConnection.isConnected();
// if (!checkConnection.isConnected()) {
// Toast.makeText(getActivity(), "No network connection", Toast.LENGTH_SHORT).show();
// }
}
public void resolveSignInError() {
if (mConnectionResult.hasResolution()) {
try {
mIntentInProgress = true;
getActivity().startIntentSenderForResult(mConnectionResult.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();
}
}
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == RC_SIGN_IN) {
if (resultCode != Activity.RESULT_OK) {
mSignInClicked = false;
}
mIntentInProgress = false;
if (!mGoogleApiClient.isConnected()) {
mGoogleApiClient.connect();
}
} else if (requestCode == RC_LOGGED_IN) {
if (resultCode == RC_SIGN_OUT) {
signOut();
}
}
}
}
答案 0 :(得分：3)
如果您使用应用程序上下文而不是活动上下文来初始化对话框，则很可能发生此异常。
您是否使用CheckConnection或类似内容初始化了getApplicationContext()个对象？如果是这样，您应该将活动作为您的上下文传递。
编辑：从评论中获取代码，您只需要更改
checkConnection = new CheckConnection(getActivity().getApplicationContext());
到
checkConnection = new CheckConnection(getActivity());