当我将Fragment添加到XML时，我的Android应用崩溃

Question

这是主要活动XML

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:tools="http://schemas.android.com/tools"
        android:id="@+id/activity_main"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="@dimen/activity_vertical_margin"
        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        android:background="#71b7d6"
        tools:context="com.csdelta.haroon.fragmentpractice.MainActivity">
<!--Binary XML file line #13  --> 
 <fragment    
        android:id="@+id/my_frag"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:name="com.csdelta.haroon.fragmentpractice.MyFragment"/>
    </LinearLayout>

这是片段活动XML

    <LinearLayout 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:background="#f7dc0f"
        tools:context="com.csdelta.haroon.fragmentpractice.MyFragment">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:text="Hello, This is Fragment"
            android:textSize="25dp"
            android:layout_margin="20dp"
            android:textColor="#000"
            />

    </LinearLayout>

这是主要活动Java文件

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d("Haroon", "onCreate");
        setContentView(R.layout.activity_main);

    }
}

这是片段Java文件

public class MyFragment extends Fragment {

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        Log.d("Haroon", "onCreateView");
        return inflater.inflate(R.layout.fragment_fragment_layout, container, false);
    }
}

我收到的logcat消息说：

java.lang.RuntimeException：无法启动活动ComponentInfo {com.csdelta.haroon.fragmentpractice / com.csdelta.haroon.fragmentpractice.MainActivity}：android.view.InflateException：二进制XML文件行＃13：二进制XML文件行13 ：错误膨胀类片段原因：android.view.InflateException：二进制XML文件行＃13：二进制XML文件行＃13：错误膨胀类片段原因：android.view.InflateException：二进制XML文件行13：错误膨胀类片段造成原因：android.app.Fragment $ InstantiationException：尝试实例化com.csdelta.haroon.fragmentpractice.MyFragment类

那不是片段

这是完整的LogCat： https : //pastebin.com/iss7ui16

Answer 1

我认为您的片段扩展支持Fragment，因此您的活动需要扩展AppCompatActivity而不是Activity。

Answer 2

像这样隐式片段到FrameLayout标签

<FrameLayout   
    android:id="@+id/my_frag"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:name="com.csdelta.haroon.fragmentpractice.MyFragment"/>

Answer 3

如果遇到相同的错误，请尝试使用FrameLayout作为

   <FrameLayout
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginBottom="70dp"/>

并将片段称为

    getSupportFragmentManager().beginTransaction().replace(R.id.container, new MyFragment()).commit();

Answer 4

将您的MainActivity更改为此

public class MainActivity extends FragmentActivity{

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    FragmentManager manager = getSupportFragmentManager();
    FragmentTransaction transaction = manager.beginTransaction();
    transaction.replace(R.id.my_frag, new MyFragment()).commit();
 }
}