Question

在我的自定义列表片段中，我显示了糖果名称及其图像列表（甜A，甜B，甜C）。请检查我的Sweet.java代码。当用户单击列表项时，它将在Fragment中显示相应的sweet。这个概念完美无缺。但我的问题是，当用户在查看相应的甜点后单击后退按钮时，列表项会显示两次。（那是甜A，甜B，甜C，甜A，甜B，甜C）。（只有前3个项目可点击）。再次，如果我点击列表项（这是甜蜜的A），它会转到甜蜜的A.如果我点击后退按钮，那么列表再次克隆自己。它显示为（甜A，甜B，甜C，甜A，甜B，甜C，甜A，甜B，甜C）。请帮帮我。

这是我的Sweet.java代码

public class Sweet extends ListFragment {
    String[] players = {"sweet A", "sweet B", "sweet C"};
    int[] images = {R.drawable.veg, R.drawable.veg2, R.drawable.veg};
    ArrayList<HashMap<String, String>> data = new ArrayList<HashMap<String, String>>();
    SimpleAdapter adapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        HashMap<String, String> map = new HashMap<String, String>();
        for (int i = 0; i < players.length; i++) {
            map = new HashMap<String, String>();
            map.put("Player", players[i]);
            map.put("Image", Integer.toString(images[i]));
            data.add(map);
        }
        String[] from = {"Player", "Image"};
        int[] to = {R.id.nameTxt, R.id.imageView1};
        adapter = new SimpleAdapter(getActivity(), data, R.layout.sweet, from, to);
        setListAdapter(adapter);
        return super.onCreateView(inflater, container, savedInstanceState);
    }

    @Override
    public void onStart() {
        super.onStart();
        getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> av, View v, int pos,
                                    long id) {
                selectItem(pos);
            }
        });
    }

    private void selectItem(int pos) {
        Fragment newFragment;
        FragmentTransaction transaction = getFragmentManager().beginTransaction();

        switch (pos) {
            case 0:
                newFragment = new SweetA();
                transaction.replace(R.id.containerID, newFragment);
                transaction.addToBackStack(null);
                transaction.commit();
                break;

            case 1:
                newFragment = new SweetB();
                transaction.replace(R.id.containerID, newFragment);
                transaction.addToBackStack(null);
                transaction.commit();
                break;
        }
    }

    @Override
    public String toString() {
        return "Home";
    }
}

这是我的sweet.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <ImageView
        android:background="@drawable/customshape"
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="20dp"
        android:layout_marginTop="10dp"
        android:layout_marginBottom="10dp"
        android:src="@drawable/veg" />
    <TextView
        android:id="@+id/nameTxt"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentRight="true"
        android:layout_alignTop="@+id/imageView1"
        android:layout_marginTop="10dp"
        android:padding="10dp"
        android:layout_toRightOf="@+id/imageView1"
        android:text="Name"
        android:textAppearance="?android:attr/textAppearanceMedium" />
</RelativeLayout>

Answer 1

OnCreate方法在片段中被调用一次，但是在第一次创建片段时调用onCreateView（），甚至当片段从backstack加载时也是如此，所以无论何时按下片段都是从backstack和acc中选取的。逻辑再次添加数据。因此，为了纠正这种情况，您可以将列表设置为本地，以防止数据一次又一次地添加。

Answer 2

这也可以解决问题。谢谢你的帮助Neha

newFragment = new SweetA();
transaction.addToBackStack(null);
transaction.hide(this);
transaction.add(R.id.containerID, newFragment);
transaction.commit();
break;

完整的代码在

下面

public class Sweet extends ListFragment {
    String[] players = {"sweet A", "sweet B", "sweet C"};
    int[] images = {R.drawable.veg, R.drawable.veg2, R.drawable.veg};
    ArrayList<HashMap<String, String>> data = new ArrayList<HashMap<String, String>>();
    SimpleAdapter adapter;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        HashMap<String, String> map = new HashMap<String, String>();
        for (int i = 0; i < players.length; i++) {
            map = new HashMap<String, String>();
            map.put("Player", players[i]);
            map.put("Image", Integer.toString(images[i]));
            data.add(map);
        }
        String[] from = {"Player", "Image"};
        int[] to = {R.id.nameTxt, R.id.imageView1};
        adapter = new SimpleAdapter(getActivity(), data, R.layout.sweet, from, to);
        setListAdapter(adapter);
        return super.onCreateView(inflater, container, savedInstanceState);
    }

    @Override
    public void onStart() {
        super.onStart();
        getListView().setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> av, View v, int pos,
                                    long id) {
                selectItem(pos);
            }
        });
    }

    private void selectItem(int pos) {
        Fragment newFragment;
        FragmentTransaction transaction = getFragmentManager().beginTransaction();

        switch (pos) {
            case 0:
                newFragment = new SweetA();
                transaction.addToBackStack(null);
                transaction.hide(this);
                transaction.add(R.id.containerID, newFragment);
                transaction.commit();
                break;

        }
    }

    @Override
    public String toString() {
        return "Home";
    }
}

每次按下后退按钮时，自定义列表片段列表项都会增加

2 个答案: