我在这里找不到错误。我可能正在寻找一些东西...
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>
包含的标题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>
列出 Activity 的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);
}
如果删除检查
if(headerLayout != null)
,则会在null
上收到headerLayout.addView(btn)
指针异常。我可以在函数
TextView
中获得setTitle
,但是有些方法无法获得LinearLayout
谁能帮我弄清楚代码出了什么问题...
最佳答案
如果为id
元素设置include
属性,则该属性将为展开式布局的根的ID。因此,与其寻找ID为LinearLayout
的headerLayout
,不如寻找ID headerInclude
(或者不为include
元素设置ID)。
关于android - findViewById在<include> d View 内的LinearLayout上返回null,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/59403836/