findViewById里面一个一个的LinearLayout返回null d图(findVi

我不能在这里找出错误。我可oevrlooking一些事情...

布局XML：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/listLayout"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="#ffffff"
    android:orientation="vertical" >

    <include
        android:id="@+id/headerInclude"
        android:layout_width="fill_parent"
        android:layout_height="38dp"
        android:layout_gravity="top"
        layout="@layout/header" />

    <LinearLayout
        android:id="@+id/actualView"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:layout_marginBottom="10dp"
        android:layout_marginTop="10dp"
        android:layout_weight="1" >

        <ListView
            android:id="@android:id/list"
            android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:divider="@drawable/dotted_line"
            android:dividerHeight="2dp"
            android:drawSelectorOnTop="false"
            android:paddingBottom="10dp"
            android:paddingTop="10dp" />
    </LinearLayout>

    <include
        android:layout_width="fill_parent"
        android:layout_height="35dp"
        android:layout_gravity="bottom"
        layout="@layout/footer" />

</LinearLayout>

包含的头XML：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/headerLayout"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:background="@drawable/header_bgr"
    android:orientation="horizontal"
    android:paddingLeft="5dp"
    android:paddingRight="5dp"
    android:paddingTop="7dp" >

    <TextView
        android:id="@+id/tvScreenTitle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="0.8"
        android:ellipsize="end"
        android:gravity="center|left"
        android:singleLine="true"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:textColor="#ffffff"
        android:textSize="17sp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/tvScreenSubTitle"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        android:layout_weight="0.2"
        android:gravity="center|right"
        android:text=""
        android:textAppearance="?android:attr/textAppearanceMedium"
        android:textColor="#ffffff"
        android:textSize="15sp"
        android:textStyle="bold" />

</LinearLayout>

清单活动java代码：

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    appData = ((DxApp) this.getApplicationContext()).getData();
    setContentView(R.layout.list);
    setTitle("Some Title...");
    // some more code...
    addButtons();
}

protected void addButtons() {
    LinearLayout headerLayout = (LinearLayout) findViewById(R.id.headerLayout);
    Button btn = new Button(this);
    btn.setText("Go to My Sets");
    btn.setOnClickListener(new View.OnClickListener() {
        public void onClick(View view) {
            // do some thing here...
        }
    });

    if (headerLayout != null)
        headerLayout.addView(btn);
}

@Override
public void setTitle(CharSequence title) {
    TextView tvTitle = (TextView) findViewById(R.id.tvScreenTitle);
    tvTitle.setText(title);
}

如果我删除检查if(headerLayout != null)我得到null的指针异常headerLayout.addView(btn)
我能得到TextView在功能上setTitle但有些怎么也无法得到LinearLayout

任何一个可以帮我搞清楚什么是错的代码...

Answer 1:

如果设置的id该属性include元素，则这将是膨胀的布局的根的ID。因此，而不是寻找一个LinearLayout与ID headerLayout认准ID headerInclude （或不设置了一个id include元素）。

Answer 2:

试试这个：

View v = getlayoutInflater().inflate(((LinearLayout)findViewById(R.id.headerInclude)), null);
TextView tvTitle = (TextView)  v.findViewById(R.id.tvScreenTitle);