Clear references to inner classes in onDestroy().

Also
- Made inner classes private if possible.
- Made some members final.

Bug 2570603

Change-Id: I34451000f2540c67e1039ea9dc4839dbec5ffab7

src/com/android/email/Utility.java

@@ -31,6 +31,7 @@ import android.content.Context;
 import android.content.res.TypedArray;
 import android.database.Cursor;
 import android.graphics.drawable.Drawable;
+import android.os.AsyncTask;
 import android.text.Editable;
 import android.util.Base64;
 import android.widget.TextView;
@@ -506,4 +507,24 @@ public class Utility {
     public static String replaceBareLfWithCrlf(String str) {
         return str.replace("\r", "").replace("\n", "\r\n");
     }
+
+    /**
+     * Cancel an {@link AsyncTask}.  If it's already running, it'll be interrupted.
+     */
+    public static void cancelTaskInterrupt(AsyncTask<?, ?, ?> task) {
+        cancelTask(task, true);
+    }
+
+    /**
+     * Cancel an {@link AsyncTask}.
+     *
+     * @param mayInterruptIfRunning <tt>true</tt> if the thread executing this
+     *        task should be interrupted; otherwise, in-progress tasks are allowed
+     *        to complete.
+     */
+    public static void cancelTask(AsyncTask<?, ?, ?> task, boolean mayInterruptIfRunning) {
+        if (task != null && task.getStatus() != AsyncTask.Status.FINISHED) {
+            task.cancel(mayInterruptIfRunning);
+        }
+    }
 }

src/com/android/email/activity/AccountFolderList.java

@@ -91,9 +91,8 @@ public class AccountFolderList extends ListActivity implements OnItemClickListen
 
     private LoadAccountsTask mLoadAccountsTask;
     private DeleteAccountTask mDeleteAccountTask;
-
+    private MessageListHandler mHandler;
-    private MessageListHandler mHandler = new MessageListHandler();
+    private ControllerResults mControllerCallback;
-    private ControllerResults mControllerCallback = new ControllerResults();
 
     /**
      * Reduced mailbox projection used by AccountsAdapter
@@ -154,6 +153,8 @@ public class AccountFolderList extends ListActivity implements OnItemClickListen
         getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE,
                 R.layout.list_title);
 
+        mHandler = new MessageListHandler();
+        mControllerCallback = new ControllerResults();
         mProgressIcon = (ProgressBar) findViewById(R.id.title_progress_icon);
 
         mListView = getListView();
@@ -203,19 +204,21 @@ public class AccountFolderList extends ListActivity implements OnItemClickListen
     @Override
     protected void onDestroy() {
         super.onDestroy();
+        Utility.cancelTaskInterrupt(mLoadAccountsTask);
+        mLoadAccountsTask = null;
 
-        if (mLoadAccountsTask != null &&
+        // TODO: We shouldn't call cancel() for DeleteAccountTask.  If the task hasn't
-                mLoadAccountsTask.getStatus() != LoadAccountsTask.Status.FINISHED) {
+        // started, this will mark it as "don't run", but we always want it to finish.
-            mLoadAccountsTask.cancel(true);
+        // (But don't just remove this cancel() call.  DeleteAccountTask.onPostExecute() checks if
-            mLoadAccountsTask = null;
+        // it's been canceled to decided whether to update the UI.)
-        }
+        Utility.cancelTask(mDeleteAccountTask, false); // Don't interrupt if it's running.
-        if (mDeleteAccountTask != null &&
+        mDeleteAccountTask = null;
-                mDeleteAccountTask.getStatus() != DeleteAccountTask.Status.FINISHED) {
-            mDeleteAccountTask.cancel(false); // false == allow the cancel to run to completion
-            mDeleteAccountTask = null;
-        }
 
         mListAdapter.changeCursor(null);
+        mListAdapter = null;
+
+        mHandler = null;
+        mControllerCallback = null;
     }
 
     public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
@@ -357,8 +360,8 @@ public class AccountFolderList extends ListActivity implements OnItemClickListen
     }
 
     private class DeleteAccountTask extends AsyncTask<Void, Void, Void> {
-        private long mAccountId;
+        private final long mAccountId;
-        private String mAccountUri;
+        private final String mAccountUri;
 
         public DeleteAccountTask(long accountId, String accountUri) {
             mAccountId = accountId;
@@ -395,10 +398,7 @@ public class AccountFolderList extends ListActivity implements OnItemClickListen
     }
 
     private void updateAccounts() {
-        if (mLoadAccountsTask != null &&
+        Utility.cancelTaskInterrupt(mLoadAccountsTask);
-                mLoadAccountsTask.getStatus() != LoadAccountsTask.Status.FINISHED) {
-            mLoadAccountsTask.cancel(true);
-        }
         mLoadAccountsTask = (LoadAccountsTask) new LoadAccountsTask().execute();
     }
 
@@ -468,6 +468,7 @@ public class AccountFolderList extends ListActivity implements OnItemClickListen
                     int numAccounts = EmailContent.count(AccountFolderList.this,
                             Account.CONTENT_URI, null, null);
                     mListAdapter.addOnDeletingAccount(mSelectedContextAccount.mId);
+
                     mDeleteAccountTask = (DeleteAccountTask) new DeleteAccountTask(
                             mSelectedContextAccount.mId,
                             mSelectedContextAccount.getStoreUri(AccountFolderList.this)).execute();
@@ -603,7 +604,7 @@ public class AccountFolderList extends ListActivity implements OnItemClickListen
     /**
      * Handler for UI-thread operations (when called from callbacks or any other threads)
      */
-    class MessageListHandler extends Handler {
+    private class MessageListHandler extends Handler {
         private static final int MSG_PROGRESS = 1;
 
         @Override
@@ -685,12 +686,12 @@ public class AccountFolderList extends ListActivity implements OnItemClickListen
 
     /* package */ static class AccountsAdapter extends CursorAdapter {
 
-        Context mContext;
+        private final Context mContext;
-        private LayoutInflater mInflater;
+        private final LayoutInflater mInflater;
-        private int mMailboxesCount;
+        private final int mMailboxesCount;
-        private int mSeparatorPosition;
+        private final int mSeparatorPosition;
-        long mDefaultAccountId;
+        private final long mDefaultAccountId;
-        ArrayList<Long> mOnDeletingAccounts = new ArrayList<Long>();
+        private final ArrayList<Long> mOnDeletingAccounts = new ArrayList<Long>();
 
         public static AccountsAdapter getInstance(Cursor mailboxesCursor, Cursor accountsCursor,
                 Context context, long defaultAccountId) {

src/com/android/email/activity/MailboxList.java

@@ -77,8 +77,8 @@ public class MailboxList extends ListActivity implements OnItemClickListener, On
     private TextView mErrorBanner;
 
     private MailboxListAdapter mListAdapter;
-    private MailboxListHandler mHandler = new MailboxListHandler();
+    private MailboxListHandler mHandler;
-    private ControllerResults mControllerCallback = new ControllerResults();
+    private ControllerResults mControllerCallback;
 
     // DB access
     private long mAccountId;
@@ -109,6 +109,8 @@ public class MailboxList extends ListActivity implements OnItemClickListener, On
         super.onCreate(icicle);
         setContentView(R.layout.mailbox_list);
 
+        mHandler = new MailboxListHandler();
+        mControllerCallback = new ControllerResults();
         mListView = getListView();
         mProgressIcon = (ProgressBar) findViewById(R.id.title_progress_icon);
         mErrorBanner = (TextView) findViewById(R.id.connection_error_text);
@@ -189,22 +191,17 @@ public class MailboxList extends ListActivity implements OnItemClickListener, On
     protected void onDestroy() {
         super.onDestroy();
 
-        if (mLoadMailboxesTask != null &&
+        Utility.cancelTaskInterrupt(mLoadMailboxesTask);
-                mLoadMailboxesTask.getStatus() != LoadMailboxesTask.Status.FINISHED) {
+        mLoadMailboxesTask = null;
-            mLoadMailboxesTask.cancel(true);
+        Utility.cancelTaskInterrupt(mLoadAccountNameTask);
-            mLoadMailboxesTask = null;
+        mLoadAccountNameTask = null;
-        }
+        Utility.cancelTaskInterrupt(mMessageCountTask);
-        if (mLoadAccountNameTask != null &&
+        mMessageCountTask = null;
-                mLoadAccountNameTask.getStatus() != LoadMailboxesTask.Status.FINISHED) {
+
-            mLoadAccountNameTask.cancel(true);
-            mLoadAccountNameTask = null;
-        }
-        if (mMessageCountTask != null &&
-                mMessageCountTask.getStatus() != MessageCountTask.Status.FINISHED) {
-            mMessageCountTask.cancel(true);
-            mMessageCountTask = null;
-        }
         mListAdapter.changeCursor(null);
+        mListAdapter = null;
+        mHandler = null;
+        mControllerCallback = null;
     }
 
     public void onClick(View v) {

src/com/android/email/activity/MessageCompose.java

@@ -150,7 +150,7 @@ public class MessageCompose extends Activity implements OnClickListener, OnFocus
     private TextView mRightTitle;
 
     private Controller mController;
-    private Listener mListener = new Listener();
+    private Listener mListener;
     private boolean mDraftNeedsSaving;
     private boolean mMessageLoaded;
     private AsyncTask mLoadAttachmentsTask;
@@ -295,6 +295,7 @@ public class MessageCompose extends Activity implements OnClickListener, OnFocus
         getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.list_title);
 
         mController = Controller.getInstance(getApplication());
+        mListener = new Listener();
         initViews();
         setDraftNeedsSaving(false);
 
@@ -376,12 +377,6 @@ public class MessageCompose extends Activity implements OnClickListener, OnFocus
         mController.removeResultCallback(mListener);
     }
 
-    private static void cancelTask(AsyncTask<?, ?, ?> task) {
-        if (task != null && task.getStatus() != AsyncTask.Status.FINISHED) {
-            task.cancel(true);
-        }
-    }
-
     /**
      * We override onDestroy to make sure that the WebView gets explicitly destroyed.
      * Otherwise it can leak native references.
@@ -391,22 +386,28 @@ public class MessageCompose extends Activity implements OnClickListener, OnFocus
         super.onDestroy();
         mQuotedText.destroy();
         mQuotedText = null;
-        cancelTask(mLoadAttachmentsTask);
+
+        Utility.cancelTaskInterrupt(mLoadAttachmentsTask);
         mLoadAttachmentsTask = null;
-        cancelTask(mLoadMessageTask);
+        Utility.cancelTaskInterrupt(mLoadMessageTask);
         mLoadMessageTask = null;
         // don't cancel mSaveMessageTask, let it do its job to the end.
+        mSaveMessageTask = null;
 
-        // TODO Make sure the three adapters don't leak their internal cursors
         if (mAddressAdapterTo != null) {
             mAddressAdapterTo.changeCursor(null);
+            mAddressAdapterTo = null;
         }
         if (mAddressAdapterCc != null) {
             mAddressAdapterCc.changeCursor(null);
+            mAddressAdapterCc = null;
         }
         if (mAddressAdapterBcc != null) {
             mAddressAdapterBcc.changeCursor(null);
+            mAddressAdapterBcc = null;
         }
+        mHandler = null;
+        mListener = null;
     }
 
     /**
@@ -1544,7 +1545,7 @@ public class MessageCompose extends Activity implements OnClickListener, OnFocus
         }
     }
 
-    class Listener implements Controller.Result {
+    private class Listener implements Controller.Result {
         public void updateMailboxListCallback(MessagingException result, long accountId,
                 int progress) {
         }

src/com/android/email/activity/MessageList.java

@@ -110,9 +110,10 @@ public class MessageList extends ListActivity implements OnItemClickListener, On
     private int mListFooterMode;
 
     private MessageListAdapter mListAdapter;
-    private MessageListHandler mHandler = new MessageListHandler();
+    private MessageListHandler mHandler;
-    private Controller mController = Controller.getInstance(getApplication());
+    private final Controller mController = Controller.getInstance(getApplication());
-    private ControllerResults mControllerCallback = new ControllerResults();
+    private ControllerResults mControllerCallback;
+
     private TextView mLeftTitle;
     private ProgressBar mProgressIcon;
 
@@ -228,6 +229,8 @@ public class MessageList extends ListActivity implements OnItemClickListener, On
         super.onCreate(icicle);
         setContentView(R.layout.message_list);
 
+        mHandler = new MessageListHandler();
+        mControllerCallback = new ControllerResults();
         mCanAutoRefresh = true;
         mListView = getListView();
         mMultiSelectPanel = findViewById(R.id.footer_organize);
@@ -315,28 +318,19 @@ public class MessageList extends ListActivity implements OnItemClickListener, On
     protected void onDestroy() {
         super.onDestroy();
 
-        if (mLoadMessagesTask != null &&
+        Utility.cancelTaskInterrupt(mLoadMessagesTask);
-                mLoadMessagesTask.getStatus() != LoadMessagesTask.Status.FINISHED) {
+        mLoadMessagesTask = null;
-            mLoadMessagesTask.cancel(true);
+        Utility.cancelTaskInterrupt(mFindMailboxTask);
-            mLoadMessagesTask = null;
+        mFindMailboxTask = null;
-        }
+        Utility.cancelTaskInterrupt(mSetTitleTask);
-        if (mFindMailboxTask != null &&
+        mSetTitleTask = null;
-                mFindMailboxTask.getStatus() != FindMailboxTask.Status.FINISHED) {
+        Utility.cancelTaskInterrupt(mSetFooterTask);
-            mFindMailboxTask.cancel(true);
+        mSetFooterTask = null;
-            mFindMailboxTask = null;
-        }
-        if (mSetTitleTask != null &&
-                mSetTitleTask.getStatus() != SetTitleTask.Status.FINISHED) {
-            mSetTitleTask.cancel(true);
-            mSetTitleTask = null;
-        }
-        if (mSetFooterTask != null &&
-                mSetFooterTask.getStatus() != SetTitleTask.Status.FINISHED) {
-            mSetFooterTask.cancel(true);
-            mSetFooterTask = null;
-        }
 
         mListAdapter.changeCursor(null);
+        mListAdapter = null;
+        mHandler = null;
+        mControllerCallback = null;
     }
 
     @Override

src/com/android/email/activity/MessageView.java

@@ -156,9 +156,9 @@ public class MessageView extends Activity implements OnClickListener {
     private Drawable mFavoriteIconOn;
     private Drawable mFavoriteIconOff;
 
-    private MessageViewHandler mHandler = new MessageViewHandler();
+    private MessageViewHandler mHandler;
     private Controller mController;
-    private ControllerResults mControllerCallback = new ControllerResults();
+    private ControllerResults mControllerCallback;
 
     private View mMoveToNewer;
     private View mMoveToOlder;
@@ -176,7 +176,7 @@ public class MessageView extends Activity implements OnClickListener {
     // this is true when reply & forward are disabled, such as messages in the trash
     private boolean mDisableReplyAndForward;
 
-    class MessageViewHandler extends Handler {
+    private class MessageViewHandler extends Handler {
         private static final int MSG_PROGRESS = 1;
         private static final int MSG_ATTACHMENT_PROGRESS = 2;
         private static final int MSG_LOAD_CONTENT_URI = 3;
@@ -346,6 +346,9 @@ public class MessageView extends Activity implements OnClickListener {
         super.onCreate(icicle);
         setContentView(R.layout.message_view);
 
+        mHandler = new MessageViewHandler();
+        mControllerCallback = new ControllerResults();
+
         mSubjectView = (TextView) findViewById(R.id.subject);
         mFromView = (TextView) findViewById(R.id.from);
         mToView = (TextView) findViewById(R.id.to);
@@ -472,22 +475,16 @@ public class MessageView extends Activity implements OnClickListener {
         }
     }
 
-    private static void cancelTask(AsyncTask<?, ?, ?> task) {
-        if (task != null && task.getStatus() != AsyncTask.Status.FINISHED) {
-            task.cancel(true);
-        }
-    }
-
     private void cancelAllTasks() {
-        cancelTask(mLoadMessageTask);
+        Utility.cancelTaskInterrupt(mLoadMessageTask);
         mLoadMessageTask = null;
-        cancelTask(mLoadBodyTask);
+        Utility.cancelTaskInterrupt(mLoadBodyTask);
         mLoadBodyTask = null;
-        cancelTask(mLoadAttachmentsTask);
+        Utility.cancelTaskInterrupt(mLoadAttachmentsTask);
         mLoadAttachmentsTask = null;
-        cancelTask(mLoadMessageListTask);
+        Utility.cancelTaskInterrupt(mLoadMessageListTask);
         mLoadMessageListTask = null;
-        cancelTask(mPresenceCheckTask);
+        Utility.cancelTaskInterrupt(mPresenceCheckTask);
         mPresenceCheckTask = null;
     }
 
@@ -505,6 +502,9 @@ public class MessageView extends Activity implements OnClickListener {
             mMessageContentView = null;
         }
         // the cursor was closed in onPause()
+
+        mHandler = null;
+        mControllerCallback = null;
     }
 
     private void onDelete() {
@@ -1433,7 +1433,7 @@ public class MessageView extends Activity implements OnClickListener {
     /**
      * Controller results listener.  This completely replaces MessagingListener
      */
-    class ControllerResults implements Controller.Result {
+    private class ControllerResults implements Controller.Result {
 
         public void loadMessageForViewCallback(MessagingException result, long messageId,
                 int progress) {
@@ -1662,7 +1662,7 @@ public class MessageView extends Activity implements OnClickListener {
         private Context mContext;
         private MediaScannerConnection mConnection;
         private File mFile;
-        MessageViewHandler mHandler;
+        private MessageViewHandler mHandler;
 
         public MediaScannerNotifier(Context context, File file, MessageViewHandler handler) {
             mContext = context;

src/com/android/email/activity/UpgradeAccounts.java

@@ -21,6 +21,7 @@ import com.android.email.Email;
 import com.android.email.LegacyConversions;
 import com.android.email.Preferences;
 import com.android.email.R;
+import com.android.email.Utility;
 import com.android.email.activity.setup.AccountSettingsUtils;
 import com.android.email.activity.setup.AccountSettingsUtils.Provider;
 import com.android.email.mail.FetchProfile;
@@ -134,11 +135,8 @@ public class UpgradeAccounts extends ListActivity implements OnClickListener {
     protected void onDestroy() {
         super.onDestroy();
 
-        if (mConversionTask != null &&
+        Utility.cancelTask(mConversionTask, false); // false = Don't interrupt running task
-                mConversionTask.getStatus() != ConversionTask.Status.FINISHED) {
+        mConversionTask = null;
-            mConversionTask.cancel(false);
-            mConversionTask = null;
-        }
     }
 
     /**

src/com/android/email/activity/Welcome.java

@@ -16,16 +16,13 @@
 
 package com.android.email.activity;
 
-import com.android.email.Account;
 import com.android.email.AccountBackupRestore;
 import com.android.email.ExchangeUtils;
-import com.android.email.Preferences;
 import com.android.email.activity.setup.AccountSetupBasics;
 import com.android.email.provider.EmailContent;
 import com.android.email.provider.EmailContent.Mailbox;
 
 import android.app.Activity;
-import android.content.Context;
 import android.content.Intent;
 import android.database.Cursor;
 import android.os.Bundle;