A first spike of integrating http://code.google.com/p/android-titlebar-webview

on my nexus 7, the webview and titlebar are overlapping each other, still

src/android/webkit/WebViewClassic.java

@@ -0,0 +1,14 @@
+package android.webkit;
+
+import android.view.View;
+
+/**
+ * Trojan class for getting access to a hidden API level 16 interface
+ */
+public class WebViewClassic {
+    public interface TitleBarDelegate {
+        int getTitleHeight();
+
+        public void onSetEmbeddedTitleBar(final View title);
+    }
+}

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

@@ -13,8 +13,8 @@ import android.widget.Toast;
 import com.fsck.k9.K9;
 import com.fsck.k9.R;
 import java.lang.reflect.Method;
-
+import com.nobu_games.android.view.web.TitleBarWebView;
-public class MessageWebView extends WebView {
+public class MessageWebView extends TitleBarWebView {
 
 
     /**
@@ -164,15 +164,4 @@ public class MessageWebView extends WebView {
         }
     }
 
-    public void wrapSetTitleBar(final View title) {
-        try {
-            Class<?> webViewClass = Class.forName("android.webkit.WebView");
-            Method setEmbeddedTitleBar = webViewClass.getMethod("setEmbeddedTitleBar", View.class);
-            setEmbeddedTitleBar.invoke(this, title);
-        }
-
-        catch (Exception e) {
-            Log.v(K9.LOG_TAG, "failed to find the  setEmbeddedTitleBar method",e);
-        }
-    }
 }

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

@@ -159,8 +159,8 @@ public class SingleMessageView extends LinearLayout implements OnClickListener,
             mHeaderContainer.setBackgroundColor(((K9Activity)activity).getThemeBackgroundColor());
 
             mTitleBarHeaderContainer = new LinearLayout(activity);
+            mMessageContentView.setEmbeddedTitleBarCompat(mTitleBarHeaderContainer);
             mTitleBarHeaderContainer.addView(mHeaderContainer);
-            mMessageContentView.wrapSetTitleBar(mTitleBarHeaderContainer);
         }
 
         mShowHiddenAttachments.setOnClickListener(this);

src/com/nobu_games/android/view/web/JBTitleBarWebView.java

@@ -0,0 +1,77 @@
+package com.nobu_games.android.view.web;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.view.View;
+import android.webkit.WebViewClassic.TitleBarDelegate;
+
+public class JBTitleBarWebView extends TitleBarWebView implements
+        TitleBarDelegate {
+
+    public JBTitleBarWebView(Context context) {
+        super(context);
+    }
+
+    public JBTitleBarWebView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+    }
+
+    public JBTitleBarWebView(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+    }
+
+    /**
+     * <i>Makes sure that the title bar view gets touch events</i>
+     * <p>
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean dispatchTouchEvent(MotionEvent event) {
+        if(mTitleBar != null) {
+            final int sy = getScrollY();
+            final int visTitleHeight = getVisibleTitleHeightCompat();
+            final float x = event.getX();
+            float y = event.getY();
+
+            switch(event.getActionMasked()) {
+                case MotionEvent.ACTION_DOWN:
+                    if(y <= visTitleHeight) {
+                        mTouchInTitleBar = true;
+                    }
+                    break;
+
+                case MotionEvent.ACTION_MOVE:
+                    mTouchMove = true;
+                    break;
+
+                case MotionEvent.ACTION_UP:
+                case MotionEvent.ACTION_CANCEL:
+                    mTouchMove = false;
+                    break;
+
+                default:
+            }
+
+            if(mTouchInTitleBar) {
+                y += sy;
+                event.setLocation(x, y);
+
+                return mTitleBar.dispatchTouchEvent(event);
+            }
+        }
+
+        return super.dispatchTouchEvent(event);
+    }
+
+    @Override
+    public int getTitleHeight() {
+        if(mTitleBar != null) return mTitleBar.getHeight();
+        return 0;
+    }
+
+    @Override
+    public void onSetEmbeddedTitleBar(View title) {
+    }
+
+}

src/com/nobu_games/android/view/web/TitleBarWebView.java

@@ -0,0 +1,340 @@
+package com.nobu_games.android.view.web;
+
+/*
+ * Copyright (C) 2012 Thomas Werner
+ * Portions Copyright (C) 2006 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Method;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Matrix;
+import android.graphics.Rect;
+import android.graphics.drawable.Drawable;
+import android.os.Build;
+import android.util.AttributeSet;
+import android.util.Log;
+import android.view.MotionEvent;
+import android.view.View;
+import android.view.ViewGroup;
+import android.webkit.WebView;
+import android.widget.FrameLayout;
+
+/**
+ * WebView derivative with custom setEmbeddedTitleBar implementation for Android
+ * versions that do not support that feature anymore.
+ * <p>
+ * <b>Usage</b>
+ * <p>
+ * Call {@link #setEmbeddedTitleBarCompat(View)} for setting a view as embedded
+ * title bar on top of the displayed WebView page.
+ */
+public class TitleBarWebView extends WebView {
+    /**
+     * Internally used view wrapper for suppressing unwanted touch events on the
+     * title bar view when WebView contents is being touched.
+     */
+    private class TouchBlockView extends FrameLayout {
+        public TouchBlockView(Context context) {
+            super(context);
+        }
+
+        @Override
+        public boolean dispatchTouchEvent(MotionEvent ev) {
+            if(!mTouchInTitleBar) {
+                return false;
+            } else {
+                switch(ev.getActionMasked()) {
+                    case MotionEvent.ACTION_UP:
+                    case MotionEvent.ACTION_CANCEL:
+                        mTouchInTitleBar = false;
+                        break;
+
+                    default:
+
+                }
+
+                return super.dispatchTouchEvent(ev);
+            }
+        }
+    }
+
+    private static final String TAG = "TitleBarWebView";
+    View mTitleBar;
+    int mTitleBarOffs;
+    boolean mTouchInTitleBar;
+    boolean mTouchMove;
+    private Rect mClipBounds = new Rect();
+    private Matrix mMatrix = new Matrix();
+    private Method mNativeGetVisibleTitleHeightMethod;
+
+    public TitleBarWebView(Context context) {
+        super(context);
+        init();
+    }
+
+    public TitleBarWebView(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        init();
+    }
+
+    public TitleBarWebView(Context context, AttributeSet attrs, int defStyle) {
+        super(context, attrs, defStyle);
+        init();
+    }
+
+    /**
+     * Gets the correct TitleBarWebView instance for the current API level.
+     *
+     * @param context
+     * @return
+     */
+    public static TitleBarWebView getInstance(Context context) {
+        if(Build.VERSION.SDK_INT >= 16) {
+            return new JBTitleBarWebView(context);
+        } else {
+            return new TitleBarWebView(context);
+        }
+    }
+
+    /**
+     * <i>Corrects the visual displacement caused by the title bar view.</i>
+     * <p>
+     * {@inheritDoc}
+     */
+    @Override
+    public boolean dispatchTouchEvent(MotionEvent event) {
+        if(mTitleBar != null) {
+            final int sy = getScrollY();
+            final int visTitleHeight = getVisibleTitleHeightCompat();
+            final float x = event.getX();
+            float y = event.getY();
+
+            switch(event.getActionMasked()) {
+                case MotionEvent.ACTION_DOWN:
+                    if(y <= visTitleHeight) {
+                        mTouchInTitleBar = true;
+                    }
+                    break;
+
+                case MotionEvent.ACTION_MOVE:
+                    mTouchMove = true;
+                    break;
+
+                case MotionEvent.ACTION_UP:
+                case MotionEvent.ACTION_CANCEL:
+                    mTouchMove = false;
+                    break;
+
+                default:
+            }
+
+            if(mTouchInTitleBar) {
+                y += sy;
+                event.setLocation(x, y);
+
+                return mTitleBar.dispatchTouchEvent(event);
+            } else {
+                if(Build.VERSION.SDK_INT < 16) {
+                    if(!mTouchMove) {
+                        mTitleBarOffs = getVisibleTitleHeightCompat();
+                    }
+
+                    y -= mTitleBarOffs;
+                    if(y < 0) y = 0;
+                    event.setLocation(x, y);
+                }
+
+                return super.dispatchTouchEvent(event);
+            }
+        } else {
+            return super.dispatchTouchEvent(event);
+        }
+    }
+
+    /**
+     * Sets a {@link View} as an embedded title bar to appear on top of the
+     * WebView page.
+     * <p>
+     * This method tries to call the hidden API method setEmbeddedTitleBar if
+     * present. On failure the custom implementation provided by this class will
+     * be used instead.
+     *
+     * @param v The view to set or null for removing the title bar view.
+     */
+    public void setEmbeddedTitleBarCompat(View v) {
+        try {
+            Method nativeMethod = getClass().getMethod("setEmbeddedTitleBar",
+                    View.class);
+            nativeMethod.invoke(this, v);
+        } catch(Exception e) {
+            Log.d(TAG,
+                    "Native setEmbeddedTitleBar not available. Starting workaround");
+            setEmbeddedTitleBarJellyBean(v);
+        }
+    }
+
+    @Override
+    protected int computeVerticalScrollExtent() {
+        if(mTitleBar == null) return super.computeVerticalScrollExtent();
+        return getViewHeightWithTitle() - getVisibleTitleHeightCompat();
+    }
+
+    @Override
+    protected int computeVerticalScrollOffset() {
+        if(mTitleBar == null) return super.computeVerticalScrollOffset();
+        return Math.max(getScrollY() - getTitleHeight(), 0);
+    }
+
+    @Override
+    protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
+        canvas.save();
+
+        if(child == mTitleBar) {
+            mTitleBar.offsetLeftAndRight(getScrollX() - mTitleBar.getLeft());
+
+            if(Build.VERSION.SDK_INT < 16) {
+                mMatrix.set(canvas.getMatrix());
+                mMatrix.postTranslate(0, -getScrollY());
+                canvas.setMatrix(mMatrix);
+            }
+        }
+
+        boolean result = super.drawChild(canvas, child, drawingTime);
+        canvas.restore();
+
+        return result;
+    }
+
+    /**
+     * Gets the currently visible height of the title bar view if set.
+     *
+     * @return Visible height of title bar view or 0 if not set.
+     */
+    protected int getVisibleTitleHeightCompat() {
+        if(mTitleBar == null && mNativeGetVisibleTitleHeightMethod != null) {
+            try {
+                return (Integer) mNativeGetVisibleTitleHeightMethod
+                        .invoke(this);
+            } catch(Exception e) {
+            }
+        }
+
+        return Math.max(getTitleHeight() - Math.max(0, getScrollY()), 0);
+    }
+
+    @Override
+    protected void onDraw(Canvas canvas) {
+        if(Build.VERSION.SDK_INT >= 16) {
+            super.onDraw(canvas);
+            return;
+        }
+
+        canvas.save();
+
+        if(mTitleBar != null) {
+            final int sy = getScrollY();
+            final int sx = getScrollX();
+            mClipBounds.top = sy;
+            mClipBounds.left = sx;
+            mClipBounds.right = mClipBounds.left + getWidth();
+            mClipBounds.bottom = mClipBounds.top + getHeight();
+            canvas.clipRect(mClipBounds);
+            mMatrix.set(canvas.getMatrix());
+            int titleBarOffs = getVisibleTitleHeightCompat();
+            if(titleBarOffs < 0) titleBarOffs = 0;
+            mMatrix.postTranslate(0, titleBarOffs);
+            canvas.setMatrix(mMatrix);
+        }
+
+        super.onDraw(canvas);
+        canvas.restore();
+    }
+
+    /**
+     * Overrides a hidden method by replicating the behavior of the original
+     * WebView class from Android 2.3.4.
+     * <p>
+     * The worst that could happen is that this method never gets called, which
+     * isn't too bad because this does not harm the functionality of this class.
+     */
+    protected void onDrawVerticalScrollBar(Canvas canvas, Drawable scrollBar,
+            int l, int t, int r, int b) {
+        int sy = getScrollY();
+
+        if(sy < 0) {
+            t -= sy;
+        }
+        scrollBar.setBounds(l, t + getVisibleTitleHeightCompat(), r, b);
+        scrollBar.draw(canvas);
+    }
+
+    private int getTitleHeight() {
+        if(mTitleBar != null) return mTitleBar.getHeight();
+        return 0;
+    }
+
+    private int getViewHeightWithTitle() {
+        int height = getHeight();
+        if(isHorizontalScrollBarEnabled() && !overlayHorizontalScrollbar()) {
+            height -= getHorizontalScrollbarHeight();
+        }
+        return height;
+    }
+
+    private void init() {
+        try {
+            mNativeGetVisibleTitleHeightMethod = WebView.class
+                    .getDeclaredMethod("getVisibleTitleHeight");
+        } catch(NoSuchMethodException e) {
+            Log.w(TAG,
+                    "Could not retrieve native hidden getVisibleTitleHeight method");
+        }
+    }
+
+    /**
+     * The hidden method setEmbeddedTitleBar has been removed from Jelly Bean.
+     * This method replicates the functionality.
+     *
+     * @param v
+     */
+    private void setEmbeddedTitleBarJellyBean(View v) {
+        if(mTitleBar == v) return;
+
+        if(mTitleBar != null) {
+            removeView(mTitleBar);
+        }
+
+        if(null != v) {
+            LayoutParams vParams = new LayoutParams(
+                    ViewGroup.LayoutParams.MATCH_PARENT,
+                    ViewGroup.LayoutParams.WRAP_CONTENT, 0, 0);
+
+            if(Build.VERSION.SDK_INT >= 16) {
+                TouchBlockView tbv = new TouchBlockView(getContext());
+                FrameLayout.LayoutParams tbvParams = new FrameLayout.LayoutParams(
+                        LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
+                tbv.addView(v, tbvParams);
+                addView(tbv, vParams);
+                v = tbv;
+            } else {
+                addView(v, vParams);
+            }
+        }
+
+        mTitleBar = v;
+    }
+}