上記の提案のいくつかを組み合わせると、良い解決策を得ることができました：
カスタムScrollView：
package com.scrollable.view;
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.ScrollView;
public class VScroll extends ScrollView {
public VScroll(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public VScroll(Context context, AttributeSet attrs) {
super(context, attrs);
}
public VScroll(Context context) {
super(context);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
return false;
}
}
カスタムHorizontalScrollView：
package com.scrollable.view;
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.widget.HorizontalScrollView;
public class HScroll extends HorizontalScrollView {
public HScroll(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public HScroll(Context context, AttributeSet attrs) {
super(context, attrs);
}
public HScroll(Context context) {
super(context);
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
return false;
}
}
ScrollableImageActivity：
package com.scrollable.view;
import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.widget.HorizontalScrollView;
import android.widget.ScrollView;
public class ScrollableImageActivity extends Activity {
private float mx, my;
private float curX, curY;
private ScrollView vScroll;
private HorizontalScrollView hScroll;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
vScroll = (ScrollView) findViewById(R.id.vScroll);
hScroll = (HorizontalScrollView) findViewById(R.id.hScroll);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float curX, curY;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mx = event.getX();
my = event.getY();
break;
case MotionEvent.ACTION_MOVE:
curX = event.getX();
curY = event.getY();
vScroll.scrollBy((int) (mx - curX), (int) (my - curY));
hScroll.scrollBy((int) (mx - curX), (int) (my - curY));
mx = curX;
my = curY;
break;
case MotionEvent.ACTION_UP:
curX = event.getX();
curY = event.getY();
vScroll.scrollBy((int) (mx - curX), (int) (my - curY));
hScroll.scrollBy((int) (mx - curX), (int) (my - curY));
break;
}
return true;
}
}
レイアウト：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="fill_parent"
android:layout_height="fill_parent">
<com.scrollable.view.VScroll android:layout_height="fill_parent"
android:layout_width="fill_parent" android:id="@+id/vScroll">
<com.scrollable.view.HScroll android:id="@+id/hScroll"
android:layout_width="fill_parent" android:layout_height="fill_parent">
<ImageView android:layout_width="fill_parent" android:layout_height="fill_parent" android:src="@drawable/bg"></ImageView>
</com.scrollable.view.HScroll>
</com.scrollable.view.VScroll>
</LinearLayout>