看起来我无法在我的简单布局中获取或设置任何位置或滚动量：
// Relative layout - main_layout
<horizontalscrollview
android:id="@+id/MenuScroll"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:fillViewport="true"
android:scrollbars="none" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="48dp"
android:orientation="horizontal"
android:layout_gravity="center"
android:padding="0dp" >
<Button
android:id="@+id/button1"
android:layout_width="150dp"
android:layout_height="fill_parent" />
<Button
android:id="@+id/button2"
android:layout_width="150dp"
android:layout_height="fill_parent" />
<Button
android:id="@+id/button3"
android:layout_width="150dp"
android:layout_height="fill_parent" />
<Button
android:id="@+id/button4"
android:layout_width="150dp"
android:layout_height="fill_parent" />
<Button
android:id="@+id/button5"
android:layout_width="150dp"
android:layout_height="fill_parent" />
</LinearLayout>
</horizontalscrollview>
// End of RelativeLayout - main_layout
我在MainActivity中想要的是获取HorizontalScrollView中任何按钮的位置并滚动到该位置.目前我无法得到左值(它始终为0),如果我尝试滚动到HorizontalScrollView,它就不会,无论x或y的值是什么.
// imports
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
final Button button3 = (Button)findViewById(R.id.button3);
Rect rectf = new Rect();
button3.getLocalVisibleRect(rectf);
Log.i("Left: ",String.valueOf(rectf.left)); // it is always 0
horizontalscrollview MenuScroll = (horizontalscrollview)findViewById(R.id.MenuScroll);
// Trying to scroll to X=100 but it doesn't
MenuScroll.scrollTo(100,MenuScroll.getBottom());
}
}
所以,正如我所说,我无法获得按钮的左侧位置,也可以滚动到我的HorizontalScrollView中的某个X位置.这可能吗？
解决方法
(it’s always 0)
请记住,视图在onCreate方法中没有维度,因为它们在onCreate回调返回后放在屏幕上.
What I want in my MainActivity is to get the position of any button
inside the horizontalscrollview and scroll to that position.
看看下面的代码(放在onCreate方法中)：
final horizontalscrollview MenuScroll = (horizontalscrollview) findViewById(R.id.MenuScroll);
MenuScroll.post(new Runnable() {
@Override
public void run() {
final Button button3 = (Button) findViewById(R.id.button3);
int scrollTo = 0;
final int count = ((LinearLayout) MenuScroll.getChildAt(0))
.getChildCount();
for (int i = 0; i < count; i++) {
final View child = ((LinearLayout) MenuScroll.getChildAt(0))
.getChildAt(i);
if (child != button3) {
scrollTo += child.getWidth();
} else {
break;
}
}
MenuScroll.scrollTo(scrollTo,0);
}
});
另外要小心你在布局中使用的属性(我指的是layout_gravity,如果我没有弄错的话可能会导致问题).