Question

我看到有关于这个主题的几个问题，但我仍然无法理解。 Android documentation声明您可以添加这样的片段： FragmentManager fragmentManager = getFragmentManager(); FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction(); ExampleFragment fragment = new ExampleFragment(); fragmentTransaction.add(R.id.fragment_container, fragment); fragmentTransaction.commit();

但是当我尝试使用我的代码时，它却找不到.add()方法......

MainActivity

import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

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

        MyFragment frag = new MyFragment();
        FragmentManager fragmentManager = getFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

        fragmentTransaction.add(R.id.myContainer, frag);
        fragmentTransaction.commit();


    }
}

MyFragment

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

/**
 * A simple {@link Fragment} subclass.
 */
public class MyFragment extends Fragment {


    public MyFragment() {
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.my_fragment, container, false);
        return rootView;
    }

}

activity_main

<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"
    android:id="@+id/myContainer"
    tools:context="com.example.alin.lynda_fragments008.MainActivity">



</FrameLayout>

my_fragment

<?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:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.alin.lynda_fragments008.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello from a fragment" />

</LinearLayout>

Answer 1

将getFragmentManager()更改为getSupportFragmentManager();

Answer 2

您不必使用SupportFragmentManager。你很可能还有其他一些问题。方法add可根据文档提供。 https://developer.android.com/reference/android/app/FragmentTransaction.html#add(int,%20android.app.Fragment)

您使用的是Android Studio吗？键入fragmentTransaction后，您应该能够看到方法的建议。（OSX上的cmd +空格）

fragmentTransaction.add（）方法问题

2 个答案: