java - 如何膨胀合并

Question

我通过适配器创建了一个帐户设置页面，其中包含部分标题和选项 ListView 。 ListView 是一个“合并”，这样它就可以包含到主文件中。然而，似乎认为合并文件不能被夸大。

这是我得到的错误:

E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.archive.pod, PID: 13046
android.view.InflateException: Binary XML file line #1 in com.archive.pod:layout/layout_center_accountsettings: <merge /> can be used only with a valid ViewGroup root and attachToRoot=true
Caused by: android.view.InflateException: <merge /> can be used only with a valid ViewGroup root and attachToRoot=true
    at android.view.LayoutInflater.inflate(LayoutInflater.java:652)
    at android.view.LayoutInflater.inflate(LayoutInflater.java:534)
    at com.archive.pod.Profile.AccountSettingsAdapter.getView(AccountSettingsAdapter.java:66)
    at android.widget.AbsListView.obtainView(AbsListView.java:2405)
    at android.widget.ListView.makeAndAddView(ListView.java:2071)
    at android.widget.ListView.fillDown(ListView.java:797)
    at android.widget.ListView.fillFromTop(ListView.java:859)
    at android.widget.ListView.layoutChildren(ListView.java:1842)
    at android.widget.AbsListView.onLayout(AbsListView.java:2202)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1103)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1103)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1103)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at androidx.coordinatorlayout.widget.CoordinatorLayout.layoutChild(CoordinatorLayout.java:1183)
    at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayoutChild(CoordinatorLayout.java:870)
    at androidx.coordinatorlayout.widget.CoordinatorLayout.onLayout(CoordinatorLayout.java:889)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
    at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
    at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
    at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
    at com.android.internal.policy.DecorView.onLayout(DecorView.java:779)
    at android.view.View.layout(View.java:22466)
    at android.view.ViewGroup.layout(ViewGroup.java:6304)
    at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3157)
    at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2614)
    at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1745)
    at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7768)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:967)
    at android.view.Choreographer.doCallbacks(Choreographer.java:791)
    at android.view.Choreographer.doFrame(Choreographer.java:726)
    at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:952)
    at android.os.Handler.handleCallback(Handler.java:883)
    at android.os.Handler.dispatchMessage(Handler.java:100)
    at android.os.Looper.loop(Looper.java:214)
    at android.app.ActivityThread.main(ActivityThread.java:7356)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

合并ListView文件layout_center_accountsettings.xml

<merge xmlns:android="http://schemas.android.com/apk/res/android">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="30dp"
        android:background="@color/windowBackground">

        <ListView
            android:id="@+id/lvAccountSettings"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:divider="@null"
            android:dividerHeight="0dp">

        </ListView>

    </RelativeLayout>

</merge>

AccountSettingsAdapter.java

package com.archive.pod.Profile;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

import com.archive.pod.R;

import java.util.ArrayList;

public class AccountSettingsAdapter extends BaseAdapter {

  ArrayList < Object > list;
  private static final int OPTIONS = 0;
  private static final int HEADER = 1;
  private LayoutInflater inflater;

  public AccountSettingsAdapter(Context context, ArrayList < Object > list) {
    this.list = list;
    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
  }

  @Override
  public int getItemViewType(int position) {

    if (list.get(position) instanceof AccountSettingsOptions) {
      return OPTIONS;

    } else {
      return HEADER;
    }
  }

  @Override
  public int getViewTypeCount() {
    return 2;
  }

  @Override
  public int getCount() {
    return list.size();
  }

  @Override
  public Object getItem(int i) {
    return list.get(i);
  }

  @Override
  public long getItemId(int i) {
    return i;
  }

  /** This distinguishes between section title and list view options,
  then using switch it beings to populate the options in the list
  view with titles and descriptions */

  @Override
  public View getView(int i, View view, ViewGroup viewGroup) {
    if (view == null) {
      switch (getItemViewType(i)) {
        case OPTIONS:
          view = inflater.inflate(R.layout.layout_center_accountsettings, null);
          break;
        case HEADER:
          view = inflater.inflate(R.layout.listview_section_header_accountsettings, null);
          break;
      }
    }
    switch (getItemViewType(i)) {
      case OPTIONS:
        TextView name = view.findViewById(R.id.listViewTitle);
        TextView description = view.findViewById(R.id.listViewDescription);

        name.setText(((AccountSettingsOptions) list.get(i)).getName());
        description.setText(((AccountSettingsOptions) list.get(i)).getDescription());
        break;
      case HEADER:

        TextView title = view.findViewById(R.id.optionListViewHeader);
        title.setText(((String) list.get(i)));
        break;
    }
    return view;
  }
}

这个特定问题的简单解决方案是什么？我看过以前的帖子，但无法完全理解他们做了什么。

Answer 1

因为getView要求您仅返回一个 View ，不幸的是你不能拥有 <merge>通过适配器作为 ListView 的直接子级。 <merge>标签只能膨胀到父级中 - 这不是这里发生的情况，因为 getView需要你用 attachToRoot = false 充气这样它就可以附加你的 View 本身。您需要将其包装在单个父布局中，例如 LinearLayout .

作为附加警告:您的项目布局似乎有 ListView在里面。 ListView s 不能很好地处理嵌套滚动 - 如果您需要这个，您可能需要查看 RecyclerView .