java - 添加 fragment 会导致崩溃

Question

我遇到了一个与 fragment 相关的问题。我有一个启动画面，它将“加载”3 秒，然后将创建一个新的 Intent 并启动 MainActivity。

主要 Activity 代码:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }
}

和相应的 XML:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:paddingLeft="@dimen/activity_horizontal_margin"
   android:paddingRight="@dimen/activity_horizontal_margin"
   android:paddingTop="@dimen/activity_vertical_margin"
   android:paddingBottom="@dimen/activity_vertical_margin"
   tools:context="com.example.paolo.ebolatrack.MainActivity">


    <fragment
       android:layout_width="fill_parent"
       android:layout_height="fill_parent"
       android:name="com.example.paolo.ebolatrack.NewsFragment"
       ></fragment>

</RelativeLayout>

和 fragment 的 xml:

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
   android:layout_height="match_parent" tools:context="com.example.paolo.ebolatrack.NewsFragment">

    <!-- TODO: Update blank fragment layout -->
    <TextView android:layout_width="match_parent" android:layout_height="match_parent"
       android:text="@string/hello_blank_fragment" />

</FrameLayout>

这是我遇到的错误(完整跟踪 here ):

10-26 12:05:05.153 2855-2855/com.example.paolo.ebolatrack E/AndroidRuntime: FATAL EXCEPTION: main
10-26 12:05:05.153 2855-2855/com.example.paolo.ebolatrack E/AndroidRuntime: Process: com.example.paolo.ebolatrack, PID: 2855
10-26 12:05:05.153 2855-2855/com.example.paolo.ebolatrack E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.paolo.ebolatrack/com.example.paolo.ebolatrack.MainActivity}: android.view.InflateException: Binary XML file line #11: Error inflating class fragment
...

添加 fragment 似乎会使应用程序崩溃。我正在使用 Android Studio。

Answer 1

这里有答案:

Caused by: java.lang.IllegalArgumentException: Binary XML file line #11: Must specify unique android:id, android:tag, or have a parent with an id for com.example.paolo.ebolatrack.NewsFragment

在布局 xml 中为您的 fragment 添加 id:

<fragment
   android:id="@+id/some_frag"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:name="com.example.paolo.ebolatrack.NewsFragment"
   ></fragment>

这是缺失的行:

 android:id="@+id/some_frag"