gistfile1.java

package com.example.wwwithscrolltest;

import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebView;
import android.widget.EditText;

public class TitleBarWebView extends WebView {
    private View mTitleBar;
    public EditText title;
    private LayoutParams mTitleBarLayoutParams;
    private Matrix mMatrix = new Matrix();
    private Rect mClipBounds = new Rect();

    public TitleBarWebView(Context context) {
        super(context);

    }

    public TitleBarWebView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public TitleBarWebView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public void setEmbeddedTitleBar(View v) {
        if(mTitleBar == v) return;
        if(mTitleBar != null) {
            removeView(mTitleBar);
        }
        if(null != v) {
        	Resources r = getResources();
        	int px = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 40, r.getDisplayMetrics());
            mTitleBarLayoutParams = new LayoutParams(
                    ViewGroup.LayoutParams.MATCH_PARENT,
                    40, 0, 0);
            addView(v, mTitleBarLayoutParams);
        }
        mTitleBar = v;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        canvas.save();

        if(mTitleBar != null) {
            final int sy = getScrollY();
            int titleBarOffs = mTitleBar.getHeight() - sy;
            if(titleBarOffs < 0) titleBarOffs = 0;
            canvas.translate(0, titleBarOffs);
        }

        super.onDraw(canvas);
        canvas.restore();
    }

    @Override
    protected boolean drawChild(Canvas canvas, View child, long drawingTime) {
        if(child == mTitleBar) {
            mTitleBar.offsetLeftAndRight((int) (getScrollX() - mTitleBar.getLeft()));
        }

        return super.drawChild(canvas, child, drawingTime);
    }
    
    @Override
	protected void onScrollChanged(int l, int t, int oldl, int oldt) {
		Log.d("SCROLL", "t = " + t + " oldT = " + oldt);
		super.onScrollChanged(l, t, oldl, oldt);
		if (t < 0)
			return;
		if (t > oldt) {
			if (title.getY() - (t - oldt) / 2 > -title.getHeight())
				title.setY(title.getY() - (t - oldt) / 2);
			else
				title.setY(-title.getHeight());
		} else if (t < oldt) {
			if (title.getY() + (oldt - t) / 2 < 0)
				title.setY(title.getY() + (oldt - t) / 2);
			else
				title.setY(0);
		}
		if (t == 0 && oldt == 0)
			title.setY(0);
	}
}