Question

我正在学习Android中的Fragments，我遇到了Logcat的问题。

我有2个活动和2个碎片及其布局：

PlayerActivity - PlayerFragment / activity_player - fragment_player

LibraryActivity - LibraryFragment / activity_library - fragment_library

我有一个PlayerFragment到LibraryActivity的按钮，在那里我给LibraryFragment充气。问题是我在LibraryFragment时Logcat没有显示任何内容。

这是我用来调用LibraryActivity的Intent（此按钮位于onActivityCreated方法的PlayerFragment中）

final Button to_library = (Button) getView().findViewById(R.id.library);
        to_library.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent newIntent = new Intent(getActivity(), LibraryActivity.class);
                startActivity(newIntent);
            }
        });

LibraryActivity：

public class LibraryActivity extends Activity {

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

        if (savedInstanceState == null) {
            getFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment()).commit();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.library, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

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

}

LibraryFragment

public class LibraryFragment extends Fragment {

    private final String LOG_TAG = "test";

    public LibraryFragment() {
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        Log.v(LOG_TAG, "onAttach");
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.v(LOG_TAG, "onCreate");
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_library, container,
                false);
        Log.v(LOG_TAG, "onCreateViewLibraryFragment");
        /*
         * Aquí podemos seleccionar las Views contenidas en el Layout para
         * trabajar con ellas, por ejemplo con: TipoView miView = (TipoView)
         * rootView.findViewById(R.id.miViewXML);
         */
        return rootView;
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        Log.v(LOG_TAG, "onActivityCreatedLibraryFragment");
    }

    @Override
    public void onStart() {
        super.onStart();
        Log.v(LOG_TAG, "onStart");

    }

    @Override
    public void onResume() {
        super.onResume();
        Log.v(LOG_TAG, "onResume");
    }

    @Override
    public void onPause() {
        super.onPause();
        Log.v(LOG_TAG, "onPause");
    }

    @Override
    public void onStop() {
        super.onStop();
        Log.v(LOG_TAG, "onStop");
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();
        Log.v(LOG_TAG, "onDestroyView");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.v(LOG_TAG, "onDestroy");
    }

    @Override
    public void onDetach() {
        super.onDetach();
        Log.v(LOG_TAG, "onDetach");
    }

}

这是我遇到问题的地方。

Logcat不会显示消息“onActivityCreatedLibraryFragment”。我有方法onStart（），onResume（），onStop（）等，他们的“Log.v”和我有同样的问题。

提前感谢您的帮助。

activity_library.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.jgutierrezgil.bmusic.LibraryActivity"
    tools:ignore="MergeRootFrame" />

fragment_library.xml

<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: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.jgutierrezgil.bmusic.LibraryActivity$PlaceholderFragment" >
</RelativeLayout>

编辑1 ：我已经完成了LibraryFragment的代码，并添加了activity_library.xml和fragment_library.xml

Answer 1

看起来您实际上从未在代码中添加LibraryFragment。您只是添加了PlaceholderFragment，这是您所做的教程中的剩余部分。

在onCreate()的{{1}}中，进行以下更改：

LibraryActivity

@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_library); if (savedInstanceState == null) { getFragmentManager().beginTransaction() //.add(R.id.container, new PlaceholderFragment()).commit(); .add(R.id.container, new LibraryFragment()).commit(); } }定义在PlaceholderFragment的底部，意为虚拟。显示正确布局的原因是因为您将输入的布局文件更改为LibraryActivity R.layout.fragment_library，表明它夸大了正确的PlaceholderFragment。

Logcat不显示片段的任何内容

1 个答案: