我最后編寫了自己的類,擴展了ScrollView
既然你問……這是代碼.可能不是最干凈但它做我想要的.
請注意,它期望在創建視圖時設置layout_weight,并且不應在父LinearLayout中設置weigthSum,否則你會得到有趣的東西(因為這個的權重從原始值變為0,具體取決于大小ScrollView的內容)
首先,在布局文件中,視圖聲明如下：
android:id="@+id/scroll"
android:scrollbars="vertical"
android:layout_height="0dp"
android:layout_width="fill_parent"
android:layout_weight="4"
android:background="#cc0000"
>
android:id="@+id/in_scroll_view"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:background="#0000bb"
/>
然后是小部件的代碼：
import android.content.Context;
import android.util.AttributeSet;
import android.widget.LinearLayout;
import android.widget.ScrollView;
public class ShrinkingScrollView extends ScrollView {
private float original_weight=-1;
public ShrinkingScrollView(Context context) {
super(context);
}
public ShrinkingScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ShrinkingScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) getLayoutParams();
float previous_weight = params.weight;
if (original_weight == -1)
original_weight = params.weight;
if ((getChildCount()>0) && (getVisibility()!=GONE)) {
super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0,MeasureSpec.UNSPECIFIED));
int overall_height = getChildAt(0).getMeasuredHeight();
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (getMeasuredHeight() >= overall_height) {
if (previous_weight != 0) {
params.weight=0;
params.height = overall_height;
setLayoutParams(params);
post(new Runnable() {
public void run() {
requestLayout();
}
});
}
setMeasuredDimension(getMeasuredWidth(),overall_height);
}
else if (previous_weight == 0) {
params.weight = original_weight;
params.height = 0;
setLayoutParams(params);
post(new Runnable() {
public void run() {
requestLayout();
}
});
}
}
else {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}
}
