Question

我是android的新手，我似乎无法理解一件事。

我正在尝试从MainActivity跳转到MainFragment。在它里面有一个按钮。当触发onClickListener时，它应该跳转到另一个ResultFragment。但我似乎无法理解如何做到这一点。

<?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: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"
    tools:context="com.something.MainActivity">

    <fragment
        android:id="@+id/container"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        tools:layout="@layout/fragment_main" />
</RelativeLayout>

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Fragment fragment = new MainFragment();
        getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment, null).commit();
    }
}

public class MainFragment extends Fragment {
    public MainFragment() {
    }

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

        Button button = (Button) rootView.findViewById(R.id.button);

        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getContext(), "iskviesta", Toast.LENGTH_SHORT).show();
                getFragmentManager().beginTransaction().replace(R.id.container, new ResultFragment()).commit();
            }
        });

        return rootView;
    }
}

public class ResultFragment extends Fragment {

    public ResultFragment() {
        // Required empty public constructor
    }

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

        return rootView;
    }
}

我做错了什么？该应用程序甚至没有启动。

E/AndroidRuntime: FATAL EXCEPTION: main
                  Process: com.something, PID: 14245
                  java.lang.RuntimeException: Unable to start activity ComponentInfo{com.something/com.something.MainActivity}: android.view.InflateException: Binary XML file line #13: Binary XML file line #13: Error inflating class fragment
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2665)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
                      at android.app.ActivityThread.-wrap12(ActivityThread.java)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6119)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
                   Caused by: android.view.InflateException: Binary XML file line #13: Binary XML file line #13: Error inflating class fragment
                   Caused by: android.view.InflateException: Binary XML file line #13: Error inflating class fragment
                   Caused by: java.lang.NullPointerException
                      at java.lang.VMClassLoader.findLoadedClass(Native Method)
                      at java.lang.ClassLoader.findLoadedClass(ClassLoader.java:742)
                      at java.lang.ClassLoader.loadClass(ClassLoader.java:362)
                      at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
                      at android.support.v4.app.Fragment.isSupportFragmentClass(Fragment.java:459)
                      at android.support.v4.app.FragmentManagerImpl.onCreateView(FragmentManager.java:3321)
                      at android.support.v4.app.FragmentController.onCreateView(FragmentController.java:120)
                      at android.support.v4.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:378)
                      at android.support.v4.app.BaseFragmentActivityHoneycomb.onCreateView(BaseFragmentActivityHoneycomb.java:33)
                      at android.support.v4.app.FragmentActivity.onCreateView(FragmentActivity.java:79)
                      at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:777)
                      at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
                      at android.view.LayoutInflater.rInflate(LayoutInflater.java:858)
                      at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821)
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:518)
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:426)
                      at android.view.LayoutInflater.inflate(LayoutInflater.java:377)
                      at android.support.v7.app.AppCompatDelegateImplV9.setContentView(AppCompatDelegateImplV9.java:288)
                      at android.support.v7.app.AppCompatActivity.setContentView(AppCompatActivity.java:143)
                      at com.something.MainActivity.onCreate(MainActivity.java:12)
                      at android.app.Activity.performCreate(Activity.java:6679)
                      at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2618)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726)
                      at android.app.ActivityThread.-wrap12(ActivityThread.java)
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
                      at android.os.Handler.dispatchMessage(Handler.java:102)
                      at android.os.Looper.loop(Looper.java:154)
                      at android.app.ActivityThread.main(ActivityThread.java:6119)
                      at java.lang.reflect.Method.invoke(Native Method)
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

Answer 1

在你的xml中使用FrameLayout而不是Fragment：

<FrameLayout
        android:id="@+id/container"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

使用片段标记不允许您在视图上执行片段事务。

Answer 2

您应该在听众中使用getSupportFragmentManager()代替getFragmentManager：

button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(getContext(), "iskviesta", Toast.LENGTH_SHORT).show();
                getSupportFragmentManager().beginTransaction().replace(R.id.container, new ResultFragment()).commit();
            }
        });

使用xml代码中的FrameLayout重新设置片段布局。

希望这有帮助。

抱歉我的英文。

从活动到片段再到另一个片段

2 个答案: