这个确切的问题已经困扰我一段时间了,但直到现在我才解决了它。
乍一看,问题在于声明性内容(在您的情况下为 TextView)有时会被实例化afterctor(我们通常会在其中膨胀布局),因此现在手头有声明性内容和模板内容将前者推入后者还为时过早。
我发现了一个这样的地方,我们可以操纵这两者:它是一个 onFinishInflate() 方法。我的情况是这样的:
@Override
protected void onFinishInflate() {
int index = getChildCount();
// Collect children declared in XML.
View[] children = new View[index];
while(--index >= 0) {
children[index] = getChildAt(index);
}
// Pressumably, wipe out existing content (still holding reference to it).
this.detachAllViewsFromParent();
// Inflate new "template".
final View template = LayoutInflater.from(getContext())
.inflate(R.layout.labeled_layout, this, true);
// Obtain reference to a new container within "template".
final ViewGroup vg = (ViewGroup)template.findViewById(R.id.layout);
index = children.length;
// Push declared children into new container.
while(--index >= 0) {
vg.addView(children[index]);
}
// They suggest to call it no matter what.
super.onFinishInflate();
}
上面引用的labeled_layout.xml 与这样的东西没有什么不同:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation ="vertical"
android:layout_width ="fill_parent"
android:layout_height ="wrap_content"
android:layout_marginLeft ="8dip"
android:layout_marginTop ="3dip"
android:layout_marginBottom ="3dip"
android:layout_weight ="1"
android:duplicateParentState ="true">
<TextView android:id ="@+id/label"
android:layout_width ="fill_parent"
android:layout_height ="wrap_content"
android:singleLine ="true"
android:textAppearance ="?android:attr/textAppearanceMedium"
android:fadingEdge ="horizontal"
android:duplicateParentState="true" />
<LinearLayout
android:id ="@+id/layout"
android:layout_width ="fill_parent"
android:layout_height ="wrap_content"
android:layout_marginLeft ="8dip"
android:layout_marginTop ="3dip"
android:duplicateParentState="true" />
</LinearLayout>
现在(仍然省略一些细节)在其他地方我们可能会像这样使用它:
<com.example.widget.LabeledLayout
android:layout_width ="fill_parent"
android:layout_height ="wrap_content">
<!-- example content -->
</com.example.widget.LabeledLayout>