Resize the fullscreen conversation window when IME appears instead of scrolling

When an activity sets FLAG_FULLSCREEN on its window, Android assumes
that the window size will always be the same as the screen size.  This
causes the window to scroll instead of resizing when the soft keyboard
comes up, which (according to a quick Google search) isn't the behavior
most developers are expecting.

This patch implements an ugly workaround: extend the root element of the
layout (in our case, a LinearLayout) to hook into the onMeasure()
callback, which is called when the window size changes, so that we can
resize ourselves when the window size changes.

application/res/layout/conversations.xml

@@ -19,7 +19,7 @@ GNU General Public License for more details.
 You should have received a copy of the GNU General Public License
 along with Yaaic.  If not, see <http://www.gnu.org/licenses/>.
 -->
-<LinearLayout
+<org.yaaic.view.ConversationLayout
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:layout_width="fill_parent"
@@ -81,4 +81,4 @@ along with Yaaic.  If not, see <http://www.gnu.org/licenses/>.
             android:drawableLeft="@android:drawable/ic_btn_speak_now"
             android:visibility="gone" />
     </LinearLayout>
-</LinearLayout>
+</org.yaaic.view.ConversationLayout>

application/src/org/yaaic/activity/ConversationActivity.java

@@ -65,6 +65,7 @@ import android.content.ServiceConnection;
 import android.content.pm.PackageManager;
 import android.content.pm.ResolveInfo;
 import android.content.res.Configuration;
+import android.graphics.Rect;
 import android.os.Bundle;
 import android.os.Handler;
 import android.os.IBinder;
@@ -84,6 +85,7 @@ import android.widget.Button;
 import android.widget.EditText;
 import android.widget.Gallery;
 import android.widget.ImageView;
+import android.widget.LinearLayout;
 import android.widget.TextView;
 import android.widget.Toast;
 import android.widget.ViewSwitcher;

application/src/org/yaaic/view/ConversationLayout.java

@@ -0,0 +1,135 @@
+/*
+Yaaic - Yet Another Android IRC Client
+
+Copyright 2009-2011 Sebastian Kaspari
+
+This file is part of Yaaic.
+
+Yaaic is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Yaaic is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Yaaic.  If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.yaaic.view;
+
+import org.yaaic.model.Settings;
+
+import android.app.Activity;
+import android.content.Context;
+import android.content.res.Configuration;
+import android.graphics.Canvas;
+import android.graphics.Rect;
+import android.util.AttributeSet;
+import android.view.Gravity;
+import android.view.View;
+import android.widget.FrameLayout;
+import android.widget.LinearLayout;
+
+/**
+ * ConversationLayout: LinearLayout that resizes correctly when an IME
+ * comes up in fullscreen mode
+ * 
+ * @author Steven Luo <steven+android@steven676.net>
+ */
+public class ConversationLayout extends LinearLayout
+{
+    Activity activity;
+    int curHeight = 0;
+    boolean fullscreen = false, isLandscape = false;
+    boolean redoLayout = false;
+
+    /**
+     * Create a new conversation view switcher
+     * 
+     * @param context
+     */
+    public ConversationLayout(Context context)
+    {
+        super(context);
+        doInit(context);
+    }
+
+    /**
+     * Create a new conversation view switcher
+     * 
+     * @param context
+     * @param attrs
+     */
+    public ConversationLayout(Context context, AttributeSet attrs)
+    {
+        super(context, attrs);
+        doInit(context);
+    }
+
+    /**
+     * Initialize the ConversationLayout
+     */
+    private void doInit(Context context)
+    {
+        activity = (Activity) context;
+        fullscreen = (new Settings(context)).fullscreenConversations();
+        isLandscape = (activity.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE);
+    }
+
+    /**
+     * Get the height of the window's visible area
+     */
+    private int getWindowHeight()
+    {
+        Rect visible = new Rect();
+        getWindowVisibleDisplayFrame(visible);
+        return visible.height();
+    }
+
+    /**
+     * onMeasure (ask the view how much space it wants)
+     * This is called when the window size changes, so we can hook into it to
+     * resize ourselves when the IME comes up
+     */
+    @Override
+    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
+    {
+        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+
+        /* XXX: We should probably use some heuristic of how many pixels are
+           available for deciding whether to scroll instead of resize, instead
+           of refusing to resize in landscape */
+        if (!fullscreen || isLandscape) {
+            return;
+        }
+
+        int height = getWindowHeight();
+        if (curHeight != height) {
+            curHeight = height;
+            FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(
+                FrameLayout.LayoutParams.FILL_PARENT,
+                height
+            );
+            params.gravity = Gravity.BOTTOM | Gravity.CLIP_VERTICAL;
+            setLayoutParams(params);
+            redoLayout = true;
+        }
+    }
+
+    /**
+     * onDraw (draw the view)
+     */
+    @Override
+    protected void onDraw(Canvas canvas)
+    {
+        if (redoLayout) {
+            // Layout params have changed -- force a layout update
+            requestLayout();
+            redoLayout = false;
+        }
+        super.onDraw(canvas);
+    }
+}