ViewStub 与 setTranslationX

开发过程中有个地方使用了ViewStub，但是发现ViewStub调用setTranslationX之后并没有任何反应，经过一番实验，发现使用inflate获取了View之后，再对View使用setTranslationX才会有效果

public class ViewStubTestActivity extends Activity {

 ViewStub sb1;
 ViewStub sb2;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main_viewstub);
  sb1 = (ViewStub) findViewById(R.id.stub_1);
  sb2 = (ViewStub) findViewById(R.id.stub_2);
  // sb1.setVisibility(View.VISIBLE); // 或者使用sb1.inflate()
  // sb1.setTranslationX(100); // 然后这个并没有效果
  sb1.inflate().setTranslationX(100); // 这个才有效
 }
}

简单读了一下源码，发现ViewStub在实例化具体内容的时候，把自己给移除了，同时将具体内容作为一个引用存了下来。而不是自身转换为目标，也不是自己将目标作为自身的子view。

所以我们应该去用这个mInflatedViewRef所指代的View
而不是用ViewStub本身。

贴一段源码。

  /**
     * Inflates the layout resource identified by {@link #getLayoutResource()}
     * and replaces this StubbedView in its parent by the inflated layout resource.
     *
     * @return The inflated layout resource.
     *
     */
    public View inflate() {
        final ViewParent viewParent = getParent();

        if (viewParent != null && viewParent instanceof ViewGroup) {
            if (mLayoutResource != 0) {
                final ViewGroup parent = (ViewGroup) viewParent;
                final LayoutInflater factory;
                if (mInflater != null) {
                    factory = mInflater;
                } else {
                    factory = LayoutInflater.from(mContext);
                }
                final View view = factory.inflate(mLayoutResource, parent,
                        false);

                if (mInflatedId != NO_ID) {
                    view.setId(mInflatedId);
                }

                final int index = parent.indexOfChild(this);
                parent.removeViewInLayout(this);

                final ViewGroup.LayoutParams layoutParams = getLayoutParams();
                if (layoutParams != null) {
                    parent.addView(view, index, layoutParams);
                } else {
                    parent.addView(view, index);
                }

                mInflatedViewRef = new WeakReference(view);

                if (mInflateListener != null) {
                    mInflateListener.onInflate(this, view);
                }

                return view;
            } else {
                throw new IllegalArgumentException("ViewStub must have a valid layoutResource");
            }
        } else {
            throw new IllegalStateException("ViewStub must have a non-null ViewGroup viewParent");
        }
}

以上。