Simplify native interface of widget implementations

Makes it easier to overwrite behavior in subclasses. Have a fallback
implementation for ViewGroup.
Save some _GET_LONG_FIELD / _SET_LONG_FIELD calls by directly passing
the native pointers to and from native methods.

src/api-impl/android/view/SurfaceView.java

@@ -3,6 +3,8 @@ package android.view;
 import android.content.Context;
 import android.graphics.Canvas;
 import android.graphics.Rect;
+import android.util.AttributeSet;
+
 import java.util.ArrayList;
 
 public class SurfaceView extends View {
@@ -12,8 +14,6 @@ public class SurfaceView extends View {
 	public SurfaceView(Context context) {
 		super(context);
 
-		native_constructor(context);
-
 		mSurface.widget = this.widget;
 	}
 
@@ -23,7 +23,8 @@ public class SurfaceView extends View {
 		}
 	}
 
-	private native void native_constructor(Context context);
+	@Override
+	protected native long native_constructor(Context context, AttributeSet attrs);
 
 	public SurfaceHolder getHolder() {
 		return mSurfaceHolder;

src/api-impl/android/view/View.java

@@ -778,7 +778,7 @@ public class View extends Object {
 	public View() {} // FIXME
 
 	public View(Context context, AttributeSet attrs) {
-		this(context);
+		this(context, attrs, 0);
 
 		if (attrs != null) {
 			id = attrs.getAttributeResourceValue("http://schemas.android.com/apk/res/android", "id", 0);
@@ -788,7 +788,9 @@ public class View extends Object {
 	}
 
 	public View(Context context, AttributeSet attrs, int defStyle) {
-		this(context, attrs);
+		this.context = context;
+
+		widget = native_constructor(context, attrs);
 	}
 
 	public View findViewById(int id) {
@@ -799,21 +801,7 @@ public class View extends Object {
 	public void onDraw(Canvas canvas) {}
 
 	public View(Context context) {
-		boolean custom_drawing;
-
-		this.context = context;
-
-		try {
-			Class[] cArg = new Class[1];
-			cArg[0] = Canvas.class;
-			custom_drawing = !(this.getClass().getMethod("onDraw", cArg).getDeclaringClass() == View.class);
-		} catch (NoSuchMethodException e) {
-			custom_drawing = false;
-		}
-
-		if (custom_drawing) {
-			native_constructor(context);
-		}
+		this(context, null);
 	}
 
 	public final ViewParent getParent() {
@@ -853,7 +841,7 @@ public class View extends Object {
 	public native final int getWidth();
 	public native final int getHeight();
 
-	private native void native_constructor(Context context); // will create a custom GtkWidget with a custom drawing function
+	protected native long native_constructor(Context context, AttributeSet attrs); // will create a custom GtkWidget with a custom drawing function
 	private native void native_set_size_request(int width, int height);
 
 	// --- stubs

src/api-impl/android/view/ViewGroup.java

@@ -6,6 +6,7 @@ import android.content.Context;
 import android.content.res.TypedArray;
 import android.util.AttributeSet;
 import java.util.ArrayList;
+import java.util.Iterator;
 
 public class ViewGroup extends View implements ViewParent, ViewManager {
 	public int id;
@@ -55,10 +56,34 @@ public class ViewGroup extends View implements ViewParent, ViewManager {
 		addView(child, new LayoutParams(width, height));
 	}
 
-	public native void addView(View child, int index, LayoutParams params);
+	public void addView(View child, int index, LayoutParams params) {
+		if (params != null) {
+			child.setLayoutParams(params);
+		}
+		child.parent = this;
+		children.add(child);
+		native_addView(widget, child.widget, index, params);
+	}
 
-	public native void removeView(View view);
-	public native void removeAllViews();
+	public void removeView(View child) {
+		child.parent = null;
+		children.remove(child);
+		native_removeView(widget, child.widget);
+	}
+
+	public void removeAllViews() {
+		for (Iterator<View> it = children.iterator(); it.hasNext();) {
+			View child = it.next();
+			child.parent = null;
+			it.remove();
+			native_removeView(widget, child.widget);
+		}
+	}
+
+	@Override
+	protected native long native_constructor(Context context, AttributeSet attrs);
+	protected native void native_addView(long widget, long child, int index, LayoutParams params);
+	protected native void native_removeView(long widget, long child);
 
 	public View getChildAt(int index) {
 		return children.get(index);