java - Android:扩展 LinearLayout 的自定义复合类认为它是 LinearLayout

Question

我正在创建一个自定义复合布局，它由一个可点击的水平 LinearLayout 组成，其中包含一个 ImageView 和两个 TextView。最终，我希望能够使用单个字段引用整个内容，并根据用户 Activity 对我的 Activity 进行添加、删除和编辑。我正在使用我在构造函数中膨胀的 XML 资源。但是我的手机认为我正在创建一个 LinearLayout，当我尝试实现自定义类时出现以下错误:

D/ConnectionButton﹕ Ready to inflate
D/ConnectionButton﹕ constructor 2
D/AndroidRuntime﹕ Shutting down VM
W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x417be898)
E/AndroidRuntime﹕ FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.exampleapp.app/com.exampleapp.app.ManageFriends}: android.view.InflateException: Binary XML file line #3: Error inflating class com.exampleapp.utils.ConnectionButton

设置NameText时的错误。如果我离开那条线，它会运行，但我后来的日志告诉我 android 认为它是 LinearLayout，而不是 ConnectionButton

所以这是我的定义类 ConnectionButton:

public class ConnectionButton extends LinearLayout {
    ImageView IconView;
    TextView  NameView;
    TextView  StatusView;

    public ConnectionButton(Context context) {
        super(context);
        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        Log.d("ConnectionButton","Ready to inflate");
        addView(inflater.inflate(R.layout.connection_row, null));
        Log.d("ConnectionButton","Inflated");
        IconView = (ImageView) findViewById(R.id.icon);
        NameView = (TextView) findViewById(R.id.name);
        StatusView = (TextView) findViewById(R.id.status);
    }

    public ConnectionButton (Context context, AttributeSet attrs) {
        super(context, attrs);
        Log.d("ConnectionButton","constructor 2");
/*        LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        Log.d("ConnectionButton","Ready to inflate");
        addView(inflater.inflate(R.layout.connection_row, null));
        Log.d("ConnectionButton","Inflated");*/
        IconView = (ImageView) this.findViewById(R.id.icon);
        NameView = (TextView) this.findViewById(R.id.name);
        StatusView = (TextView) this.findViewById(R.id.status);
        NameView.setText("From Constructor 2");
    }
}

这是我的 XML 资源:

<com.exampleapp.utils.ConnectionButton xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:orientation="horizontal"
    android:clickable="true"
    style="@android:style/Widget.Button">
        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="left"
            android:adjustViewBounds="true"
            android:paddingRight="5dp"
            android:id="@+id/icon"/>
        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:textSize="16sp"
            android:layout_weight="2"
            android:id="@+id/name"/>
        <TextView
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:textSize="16sp"
            android:layout_weight="1"
            android:id="@+id/status"/>
</com.exampleapp.utils.ConnectionButton>

这里是我创建它的地方:(注意 ConnectionList 是应该包含这些对象的现有垂直 LinearLayout)

    LinearLayout box = (LinearLayout)findViewById(R.id.ConnectionList);
    LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    Log.d("ConnectionButton","Ready to inflate");
    View CBv = inflater.inflate(R.layout.connection_row, box);
    Log.d("CBv class",CBv.getClass().toString());

Answer 1

您错误地假设 inflater.inflate 会返回新 View 。根据它返回的文档:

The root View of the inflated hierarchy. If root was supplied, this is the root View; otherwise it is the root of the inflated XML file.

因此，在您的情况下，CBv 是一个 LinearLayout，因为这就是父级。要访问您的 View ，只需使用 findViewById。