Android 使用按钮使用片段更改布局

所以我试图用一个使用fragment的按钮来改变我的布局，但我无法让它工作，可能是因为我不太理解它是如何工作的。总体来说，我对编程非常陌生，所以我在理解一些东西时有点困难。不管怎样，这就是我想做的

主要活动

public class MainActivity extends ActionBarActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    FragmentManager fragmentManager = getFragmentManager();
    FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

    Fragmenttwo thenewfrag = new Fragmenttwo();
    fragmentTransaction.replace(android.R.id.content, thenewfrag);

    Button splay = (Button) findViewById(R.id.splay);

    splay.setOnClickListener(new View.OnClickListener(){
    public void onClick(View v) {
          FragmentManager fragmentManager = getFragmentManager();
          FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();

          Fragmentone newfrag = new Fragmentone();
          fragmentTransaction.replace(android.R.id.content, newfrag);

          fragmentTransaction.commit();
    }
});
fragmentTransaction.commit();
}
}

碎片

public class Fragmentone extends Fragment {

 public Fragmentone() {}

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

    }
}

碎片二

public class Fragmenttwo extends Fragment{

 public Fragmenttwo() {}

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

    }
}

main menu.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/mainmenu"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/mainmenu" >

<Button
    android:id="@+id/splay"
    android:layout_width="195dp"
    android:layout_height="64dp"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true" />

</RelativeLayout>

---

有没有办法解决这个问题？或者如何使用按钮更改布局？

您的按钮splay位于mainmenu.xml中，它加载在FragmentOne中。因此，您需要找到如下参考：

public class Fragmentone extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.mainmenu, container, false);
        Button splay = (Button) view.findViewById(R.id.splay);
        //onClick here
        return view;
    }
}

您的按钮显示为空。所以你得到了

E/AndroidRuntime(2001): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.gerfort.gerfortrps/com.gerfort.gerfortrps.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference

希望能有帮助

---

附言：为了更好地理解片段

在这之后似乎仍然会崩溃，同样的错误。结合你在fragmentone和jaydroiders代码中加入onClick的技巧，它工作得很好。非常感谢。内容无法解析。这也不起作用。编辑：我的文字写错了，效果很好！（在“R.id.content”之前添加“android”之后）

Button yourButton = (Button) rootView
            .findViewById(R.id.btnid);
    yourButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            Fragment newFragment = new YourFragment();
            FragmentTransaction transaction = getFragmentManager()
                    .beginTransaction();

            // Replace whatever is in the fragment_container view with this
            // fragment,
            // and add the transaction to the back stack
            transaction.replace(android.R.id.content, newFragment);
            transaction.addToBackStack("tag");

            // Commit the transaction
            transaction.commitAllowingStateLoss();

        }
    });

Button yourButton = (Button) rootView
            .findViewById(R.id.btnid);
    yourButton.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

            Fragment newFragment = new YourFragment();
            FragmentTransaction transaction = getFragmentManager()
                    .beginTransaction();

            // Replace whatever is in the fragment_container view with this
            // fragment,
            // and add the transaction to the back stack
            transaction.replace(android.R.id.content, newFragment);
            transaction.addToBackStack("tag");

            // Commit the transaction
            transaction.commitAllowingStateLoss();

        }
    });