Android:多视图子视图，用于现有布局的自定义视图
Android:多视图子视图，用于现有布局的自定义视图
提问于 2012-06-26 06:02:42
我必须在Android中构建一个更复杂的自定义视图。最终的布局应该如下所示：
<RelativeLayout>
<SomeView />
<SomeOtherView />
<!-- maybe more layout stuff here later -->
<LinearLayout>
<!-- the children -->
</LinearLayout>
</RelativeLayout>但是，我只想在XML文件中定义这个(不定义SomeView、SomeOtherView等)：
<MyCustomView>
<!-- the children -->
</MyCustomView>这在Android中是可能的吗?如果可能:最干净的方式是什么？我想到的可能的解决方案是“覆盖addView()方法”和“删除所有视图，稍后再添加它们”，但我不确定该走哪条路……
非常感谢您的帮助！:)
回答 1
Stack Overflow用户
回答已采纳
发布于 2012-06-26 06:22:30
创建自定义容器视图是完全可能的，也是鼓励的。这就是Android所说的复合控件。所以：
public class MyCustomView extends RelativeLayout {
private LinearLayout mContentView;
public MyCustomView(Context context) {
this(context, null);
}
public MyCustomView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public MyCustomView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
//Inflate and attach your child XML
LayoutInflater.from(context).inflate(R.layout.custom_layout, this);
//Get a reference to the layout where you want children to be placed
mContentView = (LinearLayout) findViewById(R.id.content);
//Do any more custom init you would like to access children and do setup
}
@Override
public void addView(View child, int index, ViewGroup.LayoutParams params) {
if(mContentView == null){
super.addView(child, index, params);
} else {
//Forward these calls to the content view
mContentView.addView(child, index, params);
}
}
}您可以根据需要覆盖任意多个版本的addView()，但最终它们都会回调到我放在示例中的版本。仅覆盖此方法将使框架将其XML标记中找到的所有子对象传递给特定的子容器。
然后按如下方式修改XML：
res/layout/custom_layout.xml
<merge>
<SomeView />
<SomeOtherView />
<!-- maybe more layout stuff here later -->
<LinearLayout
android:id="@+id/content" />
</merge>使用<merge>的原因是为了简化层次结构。所有的子视图都将附加到您的自定义类，这是一个RelativeLayout。如果您不使用<merge>，您最终会得到一个连接到另一个RelativeLayout的RelativeLayout，该RelativeLayout连接到所有子进程，这可能会导致问题。
Kotlin版本：
private fun expand(view: View) {
val parentWidth = (view.parent as View).width
val matchParentMeasureSpec = MeasureSpec.makeMeasureSpec(parentWidth, MeasureSpec.EXACTLY)
val wrapContentMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)
view.measure(matchParentMeasureSpec, wrapContentMeasureSpec)
val targetHeight = view.measuredHeight
view.isVisible = true
val animation: Animation = getExpandAnimation(view, targetHeight)
view.startAnimation(animation)
}
private fun getExpandAnimation(
view: View,
targetHeight: Int
): Animation = object : Animation() {
override fun applyTransformation(
interpolatedTime: Float,
transformation: Transformation
) {
view.layoutParams.height =
if (interpolatedTime == 1f) {
LayoutParams.WRAP_CONTENT
} else {
(targetHeight * interpolatedTime).toInt()
}
view.requestLayout()
}
override fun willChangeBounds(): Boolean {
return true
}
}.apply {
duration = getDuration(targetHeight, view)
}
private fun collapse(view: View) {
val initialHeight = view.measuredHeight
val animation: Animation = getCollapseAnimation(view, initialHeight)
view.startAnimation(animation)
}
private fun getCollapseAnimation(
view: View,
initialHeight: Int
): Animation = object : Animation() {
override fun applyTransformation(
interpolatedTime: Float,
transformation: Transformation
) {
if (interpolatedTime == 1f) {
view.isVisible = false
} else {
view.layoutParams.height =
initialHeight - (initialHeight * interpolatedTime).toInt()
view.requestLayout()
}
}
override fun willChangeBounds(): Boolean = true
}.apply {
duration = getDuration(initialHeight, view)
}
/**
* Speed = 1dp/ms
*/
private fun getDuration(initialHeight: Int, view: View) =
(initialHeight / view.context.resources.displayMetrics.density).toLong()页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/11198026
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