fragment或adapter中使用LayoutInflater加载布局时出现的问题

一般情况下，我们在fragment或是adapter中加载布局都是如此使用：

inflater.inflate(R.layout.fragment_recommend,container,false);

其中false意思为：把布局添加到父视图中，并保留父视图中的其他视图；

而infate方法也可以省略boolean 参数，而如果省略了Boolean变量，而container不为空的情况下，第三个参数默认是为true的，即：

public View inflate(@LayoutRes int resource, @Nullable ViewGroup root) {    return inflate(resource, root, root != null);}

这个时候如果我们调用

inflater.inflate(R.layout.fragment_recommend,container)

则表示，要删除父视图中其他子视图。于是可能就会报如下的错误了。所以还是乖乖的添加false吧。

12-25 17:16:26.870 6580-6580/? E/AndroidRuntime: FATAL EXCEPTION: main
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.addViewInner(ViewGroup.java:3381)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.addView(ViewGroup.java:3252)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.addView(ViewGroup.java:3197)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.RecyclerView$4.addView(RecyclerView.java:544)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.ChildHelper.addView(ChildHelper.java:107)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.RecyclerView$LayoutManager.addViewInt(RecyclerView.java:6314)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:6272)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.RecyclerView$LayoutManager.addView(RecyclerView.java:6260)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1385)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1334)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:563)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.RecyclerView.dispatchLayout(RecyclerView.java:2847)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.support.v7.widget.RecyclerView.onLayout(RecyclerView.java:3145)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.View.layout(View.java:13772)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.layout(ViewGroup.java:4365)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:948)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.View.layout(View.java:13772)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.layout(ViewGroup.java:4365)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:948)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.View.layout(View.java:13772)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.layout(ViewGroup.java:4365)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.View.layout(View.java:13772)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.layout(ViewGroup.java:4365)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.widget.RelativeLayout.onLayout(RelativeLayout.java:948)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.View.layout(View.java:13772)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.layout(ViewGroup.java:4365)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.View.layout(View.java:13772)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.layout(ViewGroup.java:4365)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1649)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1507)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.widget.LinearLayout.onLayout(LinearLayout.java:1420)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.View.layout(View.java:13772)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.layout(ViewGroup.java:4365)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.View.layout(View.java:13772)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewGroup.layout(ViewGroup.java:4365)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1866)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1687)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4212)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.Choreographer.doCallbacks(Choreographer.java:555)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.Choreographer.doFrame(Choreographer.java:525)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.os.Handler.handleCallback(Handler.java:615)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:92)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:137)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:4745)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at java.lang.reflect.Method.invokeNative(Native Method)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:511)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-25 17:16:26.870 6580-6580/? E/AndroidRuntime:     at dalvik.system.NativeStart.main(Native Method)

另外一个问题，如果parent参数传空的话，再怎么改变根布局 的长宽属性（即fragment_recommend布局文件的跟布局长宽），始终是已包裹内容的方式来布局

inflater.inflate(R.layout.fragment_recommend,null)

例如

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"        android:id="@+id/ll_home_f_channel_item_bg"        android:layout_centerInParent="true"        android:layout_width="220dp"        android:layout_height="200dp"        android:gravity="center"        android:orientation="vertical"        android:focusable="true"        android:background="@mipmap/home_f_channel_1_bg"        >        <RelativeLayout            android:id="@+id/rl_recomm_channel"            android:layout_width="match_parent"            android:layout_height="120dp"/>

</LinearLayout>

不论我如何改变父布局（这里是LinearLayout）的高度，经过inflate加载的布局的高度始终以子布局（这里是RelativeLayout）的高度为准。

所以如果要得到根布局的高度，则parent不能传空。