Merge pull request #83 from andrewachen/messageview_save_location

Restore position in MessageView after rotation screen.

src/com/fsck/k9/activity/MessageView.java

@@ -35,6 +35,7 @@ public class MessageView extends K9Activity implements OnClickListener {
     private static final String EXTRA_MESSAGE_REFERENCE = "com.fsck.k9.MessageView_messageReference";
     private static final String EXTRA_MESSAGE_REFERENCES = "com.fsck.k9.MessageView_messageReferences";
     private static final String EXTRA_NEXT = "com.fsck.k9.MessageView_next";
+    private static final String EXTRA_SCROLL_PERCENTAGE = "com.fsck.k9.MessageView_scrollPercentage";
     private static final String SHOW_PICTURES = "showPictures";
     private static final String STATE_PGP_DATA = "pgpData";
     private static final int ACTIVITY_CHOOSE_FOLDER_MOVE = 1;
@@ -372,13 +373,19 @@ public class MessageView extends K9Activity implements OnClickListener {
                 }
             };
         });
+
         mMessageView.initialize(this);
 
+        // Register the ScrollView's listener to handle scrolling to last known location on resume.
+        mController.addListener(mTopView.getListener());
+        mMessageView.setListeners(mController.getListeners());
+
         setTitle("");
         final Intent intent = getIntent();
 
         Uri uri = intent.getData();
         if (icicle != null) {
+            // TODO This code seems unnecessary since the icicle should already be thawed in onRestoreInstanceState().
             mMessageReference = icicle.getParcelable(EXTRA_MESSAGE_REFERENCE);
             mMessageReferences = icicle.getParcelableArrayList(EXTRA_MESSAGE_REFERENCES);
             mPgpData = (PgpData) icicle.getSerializable(STATE_PGP_DATA);
@@ -492,6 +499,7 @@ public class MessageView extends K9Activity implements OnClickListener {
         outState.putParcelableArrayList(EXTRA_MESSAGE_REFERENCES, mMessageReferences);
         outState.putSerializable(STATE_PGP_DATA, mPgpData);
         outState.putBoolean(SHOW_PICTURES, mMessageView.showPictures());
+        outState.putDouble(EXTRA_SCROLL_PERCENTAGE, mTopView.getScrollPercentage());
     }
 
     @Override
@@ -500,6 +508,7 @@ public class MessageView extends K9Activity implements OnClickListener {
         mPgpData = (PgpData) savedInstanceState.getSerializable(STATE_PGP_DATA);
         mMessageView.updateCryptoLayout(mAccount.getCryptoProvider(), mPgpData, mMessage);
         mMessageView.setLoadPictures(savedInstanceState.getBoolean(SHOW_PICTURES));
+        mTopView.setScrollPercentage(savedInstanceState.getDouble(EXTRA_SCROLL_PERCENTAGE));
     }
 
     private void displayMessage(MessageReference ref) {
@@ -619,11 +628,13 @@ public class MessageView extends K9Activity implements OnClickListener {
             onAccountUnavailable();
             return;
         }
+        mController.addListener(mTopView.getListener());
         StorageManager.getInstance(getApplication()).addListener(mStorageListener);
     }
 
     @Override
     protected void onPause() {
+        mController.removeListener(mTopView.getListener());
         StorageManager.getInstance(getApplication()).removeListener(mStorageListener);
         super.onPause();
     }
@@ -850,6 +861,8 @@ public class MessageView extends K9Activity implements OnClickListener {
     }
 
     protected void onNext() {
+        // Reset scroll percentage when we change messages
+        mTopView.setScrollPercentage(0);
         if (mNextMessage == null) {
             Toast.makeText(this, getString(R.string.end_of_folder), Toast.LENGTH_SHORT).show();
             return;
@@ -864,6 +877,8 @@ public class MessageView extends K9Activity implements OnClickListener {
     }
 
     protected void onPrevious() {
+        // Reset scroll percentage when we change messages
+        mTopView.setScrollPercentage(0);
         if (mPreviousMessage == null) {
             Toast.makeText(this, getString(R.string.end_of_folder), Toast.LENGTH_SHORT).show();
             return;
@@ -1091,8 +1106,8 @@ public class MessageView extends K9Activity implements OnClickListener {
                 mTopView.scrollTo(0, 0);
                 try {
                     if (MessageView.this.mMessage != null
-                            && MessageView.this.mMessage.isSet(Flag.X_DOWNLOADED_PARTIAL)
+                        && MessageView.this.mMessage.isSet(Flag.X_DOWNLOADED_PARTIAL)
-                    && message.isSet(Flag.X_DOWNLOADED_FULL)) {
+                        && message.isSet(Flag.X_DOWNLOADED_FULL)) {
                         mMessageView.setHeaders(message, account);
                     }
                     MessageView.this.mMessage = message;
@@ -1252,5 +1267,4 @@ public class MessageView extends K9Activity implements OnClickListener {
         // sometimes shows the original encrypted content
         mMessageView.loadBodyFromText(mAccount.getCryptoProvider(), mPgpData, mMessage, mPgpData.getDecryptedData(), "text/plain");
     }
-
 }

src/com/fsck/k9/controller/MessagingListener.java

@@ -112,6 +112,11 @@ public class MessagingListener {
     public void loadMessageForViewFailed(Account account, String folder, String uid, Throwable t) {
     }
 
+    /**
+     * Called when a message for view has been fully displayed on the screen.
+     */
+    public void messageViewFinished() {}
+
     public void checkMailStarted(Context context, Account account) {
     }
 

src/com/fsck/k9/view/AccessibleWebView.java

@@ -26,11 +26,15 @@ import android.webkit.WebView;
 import android.widget.TextView;
 
 import com.fsck.k9.activity.AccessibleEmailContentActivity;
+import com.fsck.k9.controller.MessagingListener;
+
+import java.util.Set;
 
 public class AccessibleWebView extends TextView {
     private Context mContext;
     private String mHtmlSource;
     private WebView mDummyWebView;
+    private Set<MessagingListener> mListeners = null;
 
     public AccessibleWebView(Context context) {
         super(context);
@@ -68,6 +72,13 @@ public class AccessibleWebView extends TextView {
                                     String historyUrl) {
         mHtmlSource = data;
         this.setText(Html.fromHtml(mHtmlSource, null, null));
+
+        // Let everyone know that loading has finished.
+        if (mListeners != null) {
+            for (MessagingListener l : mListeners) {
+                l.messageViewFinished();
+            }
+        }
     }
 
     public boolean zoomIn() {
@@ -92,4 +103,8 @@ public class AccessibleWebView extends TextView {
         i.putExtra("content", mHtmlSource);
         mContext.startActivity(i);
     }
+
+    public void setListeners(final Set<MessagingListener> listeners) {
+        this.mListeners = listeners;
+    }
 }

src/com/fsck/k9/view/MessageWebView.java

@@ -1,6 +1,7 @@
 package com.fsck.k9.view;
 
 import android.content.Context;
+import android.graphics.Picture;
 import android.os.Build;
 import android.util.AttributeSet;
 import android.util.Log;
@@ -10,10 +11,15 @@ import android.webkit.WebView;
 import android.widget.Toast;
 import com.fsck.k9.K9;
 import com.fsck.k9.R;
+import com.fsck.k9.controller.MessagingListener;
 
 import java.lang.reflect.Method;
+import java.util.Set;
 
 public class MessageWebView extends WebView {
+    // Store a reference to the listeners in MessagingController.  We can't fetch it directly since
+    // we don't know the application name.
+    private Set<MessagingListener> mListeners = null;
 
     /**
      * We use WebSettings.getBlockNetworkLoads() to prevent the WebView that displays email
@@ -97,6 +103,18 @@ public class MessageWebView extends WebView {
 
         // Disable network images by default.  This is overridden by preferences.
         blockNetworkData(true);
+
+        // Listen for when the screen has finished drawing.
+        setPictureListener(new PictureListener() {
+            @Override
+            public void onNewPicture(WebView webView, Picture picture) {
+                if (mListeners != null) {
+                    for (MessagingListener l : mListeners) {
+                        l.messageViewFinished();
+                    }
+                }
+            }
+        });
     }
 
     /*
@@ -115,4 +133,8 @@ public class MessageWebView extends WebView {
             Log.e(K9.LOG_TAG, "Exception in emulateShiftHeld()", e);
         }
     }
+
+    public void setListeners(final Set<MessagingListener> listeners) {
+        this.mListeners = listeners;
+    }
 }

src/com/fsck/k9/view/SingleMessageView.java

@@ -29,6 +29,7 @@ import com.fsck.k9.mail.internet.MimeUtility;
 import com.fsck.k9.mail.store.LocalStore;
 
 import java.util.List;
+import java.util.Set;
 
 
 /**
@@ -116,11 +117,10 @@ public class SingleMessageView extends LinearLayout {
         return false;
     }
 
-
-
     public boolean showPictures() {
         return mShowPictures;
     }
+
     public void setShowPictures(Boolean show) {
         mShowPictures = show;
     }
@@ -312,4 +312,21 @@ public class SingleMessageView extends LinearLayout {
         AttachmentView.AttachmentFileDownloadCallback attachmentCallback) {
         this.attachmentCallback = attachmentCallback;
     }
+
+    /**
+     * Save a copy of the {@link com.fsck.k9.controller.MessagingController#getListeners()}.  This method will also
+     * pass along these listeners to the underlying views.
+     * @param listeners Set of listeners.
+     */
+    public void setListeners(final Set<MessagingListener> listeners) {
+        if(!mScreenReaderEnabled) {
+            if(mMessageContentView != null) {
+                mMessageContentView.setListeners(listeners);
+            }
+        } else {
+            if(mAccessibleMessageContentView != null) {
+                mAccessibleMessageContentView.setListeners(listeners);
+            }
+        }
+    }
 }

src/com/fsck/k9/view/ToggleScrollView.java

@@ -2,13 +2,22 @@ package com.fsck.k9.view;
 
 import android.content.Context;
 import android.util.AttributeSet;
+import android.util.Log;
 import android.view.GestureDetector;
 import android.view.MotionEvent;
 import android.widget.ScrollView;
+import com.fsck.k9.K9;
+import com.fsck.k9.controller.MessagingListener;
 
+/**
+ * An extension of {@link ScrollView} that allows scrolling to be selectively disabled.
+ */
 public class ToggleScrollView extends ScrollView {
     private GestureDetector mDetector;
     private boolean mScrolling = true;
+    private int mCurrentYPosition;
+    private double mScrollPercentage;
+    private ScrollToLastLocationListener mListener;
 
     public ToggleScrollView(Context context, AttributeSet attrs) {
         super(context, attrs);
@@ -59,4 +68,76 @@ public class ToggleScrollView extends ScrollView {
             return false;
         }
     }
+
+    /**
+     * Fetch the current percentage by which this view has been scrolled.
+     * @return Scroll percentage based on the top edge of the screen, from 0 to 100.  This number should never really
+     * be 100, unless the screen is of 0 height...
+     */
+    public double getScrollPercentage() {
+        // We save only the Y coordinate instead of the percentage because I don't know how expensive the
+        // computeVerticalScrollRange() call is.
+        final int scrollRange = computeVerticalScrollRange();
+        if(scrollRange == 0) {
+            return 0;
+        }
+        return (double) mCurrentYPosition / scrollRange;
+    }
+
+    /**
+     * Set the percentage by which we should scroll the page once we get the load complete event.  This is
+     * based on the top edge of the view.
+     * @param percentage Percentage of page to scroll to.
+     */
+    public void setScrollPercentage(final double percentage) {
+        Log.d(K9.LOG_TAG, "ToggleView: Setting last scroll percentage to " + percentage);
+        this.mScrollPercentage = percentage;
+    }
+
+    /**
+     * Override {@link ScrollView#onScrollChanged(int, int, int, int)} to record the current x/y position.  We use this
+     * to save our current position for future scrolling.
+     *
+     * @param x
+     * @param y
+     * @param oldx
+     * @param oldy
+     */
+    @Override
+    protected void onScrollChanged(int x, int y, int oldx, int oldy) {
+        super.onScrollChanged(x, y, oldx, oldy);
+
+        this.mCurrentYPosition = y;
+        // I wish Android has a TRACE log level so I wouldn't have to comment this out.  This one is really noisy.
+        // Log.d(K9.LOG_TAG, "ToggleScrollView: mCurrentYPosition=" + y + " scrollRange=" + computeVerticalScrollRange() + " pct=" + getScrollPercentage());
+    }
+
+    /**
+     * This is a {@link MessagingListener} which listens for when the a message has finished being displayed on the
+     * screen.  We'll scroll the message to the user's last known location once it's done.
+     */
+    class ScrollToLastLocationListener extends MessagingListener {
+        public void messageViewFinished() {
+            // Don't scroll if our last position was at the top.
+            if(mScrollPercentage != 0.0) {
+                final int scrollRange = computeVerticalScrollRange();
+                final int newY = (int)(mScrollPercentage * scrollRange);
+                Log.d(K9.LOG_TAG, "ToggleScrollView: requested " + (100 * mScrollPercentage) + "%, " +
+                    "scrolling to " + newY + "/" + scrollRange);
+                scrollTo(0, newY);
+            }
+        }
+    }
+
+    /**
+     * Fetch the {@link MessagingListener} for this <code>ScrollView</code>.
+     * @return
+     */
+    public MessagingListener getListener() {
+        if(this.mListener != null) {
+            return this.mListener;
+        } else {
+            return this.mListener = new ScrollToLastLocationListener();
+        }
+    }
 }