如何通过主活动更新片段之间的列表视图内容

Question

我有三个片段，第二个和第三个，在它们各自的布局中有一个listView。

换句话说，最初第二个片段和第三个片段的listView包含以下内容，其中CB：是检查框，IV：是ImageView，t是： text view，SaveButton是一个按钮

t1........CB.......IV
t2........CB.......IV
t3........CB.......IV
t4........CB.......IV
t5........CB.......IV
t6........CB.......IV
    SaveButton

我想做的是，当我在第二个片段中，并“使用复选框”从listView中选择一个项目，然后单击“保存”按钮时，我选择的项目应该从第三个片段的listView中删除。

为了实现这一点，在getview（）中，我检查了第二个片段的listView中是否选中了复选框，如果选中了，我将选中的项目添加到列表中。如getView（）所示：

第二个片段：

private void setUpListView() {
    // TODO Auto-generated method stub
    this.topicsList = new ArrayList<String>();

    for (int i = 0; i < this.topics.length; i++) {
        this.topicsList.add(topics[i]);
    }

    this.adapter = new ListViewAdapter(getActivity(), this.topicsList, ECO_FRAG_ID);
    this.listView.setAdapter(adapter);
}

第三个片段：

private void setUpListView() {
    // TODO Auto-generated method stub
    this.topicsList = new ArrayList<String>();

    for (int i = 0; i < this.topics.length; i++) {
        this.topicsList.add(topics[i]);
    }

    this.adapter = new ListViewAdapter(getActivity(), this.topicsList, LOGGER_FRAG_ID);
    this.listView.setAdapter(adapter);
}

基本适配器：

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    // TODO Auto-generated method stub

    if (convertView == null) {
        LayoutInflater layoutinflater = (LayoutInflater) context.getSystemService(Activity.LAYOUT_INFLATER_SERVICE);
        convertView = layoutinflater.inflate(R.layout.list_items_layout, null);
    }

    if (this.checkedItemsList1 == null) {
        this.checkedItemsList1 = new ArrayList<String>();
    }

    if (this.checkedItemsList2 == null) {
        this.checkedItemsList2 = new ArrayList<String>();
    }

    final TextView tv = (TextView) convertView.findViewById(R.id.tvlist_topic);
    final CheckBox cb = (CheckBox) convertView.findViewById(R.id.cbList_hook);
    final ImageView iv = (ImageView) convertView.findViewById(R.id.ivList_delete);

    tv.setText(this.topicsList.get(position));

    if (cb.isChecked() && (this.id == 1) ) {
        this.checkedItemsList1.add(this.topicsList.get(position));
        this.setCheckedItemsList1(this.checkedItemsList1);
    }
    if (cb.isChecked() && (this.id == 2) ) {
        this.checkedItemsList2.add(this.topicsList.get(position));
        this.setCheckedItemsList2(this.checkedItemsList2);
    }

    iv.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            if (cb.isChecked())
                cb.setChecked(false);

            topicsList.remove(position);
            notifyDataSetChanged();
        }
    });

    return convertView;
}

我创建了一个接口，它在onAttach（）中初始化，并在我单击第二个片段中的savebuton时调用，如下所示：

private OnClickListener btnSaveListener = new OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        Toast.makeText(getActivity(), "Save to SQLite", Toast.LENGTH_SHORT).show();
        Log.d(TAG, "size: " + adapter.getCheckedItemsList1().size());
        iCSC.onCheckedStateChanged(adapter.checkedItemsList1, ECO_FRAG_ID);
    }
};

这个接口，main Active实现了它，在接口的实现中，我通过第三个片段中的公共方法将检查过的项目从第二个片段传递到第三个片段，更新列表，然后将列表分配给适配器，如下所示：

@Override
public void onCheckedStateChanged(ArrayList<String> list, int id) {
    // TODO Auto-generated method stub

    switch (id) {
    case 1:
        ((Logger_Settings_Frag) this.fragList.get(2)).updateTopicList(list);
        break;
    case 2:

        break;
    }
}

**updateTopicList in the third fragment**

public void updateTopicList(ArrayList<String> list) {
    for (String str : list) {
        this.topicsList.remove(str);
    }

    this.adapter = new ListViewAdapter(getActivity(), this.topicsList, LOGGER_FRAG_ID);
    this.listView.setAdapter(adapter);
}

第三个片段中的updateTopicList

public void updateTopicList(ArrayList<String> list) {
    for (String str : list) {
        this.topicsList.remove(str);
    }

    this.adapter = new ListViewAdapter(getActivity(), this.topicsList, LOGGER_FRAG_ID);
    this.listView.setAdapter(adapter);
}

当我运行该代码时，在第二个片段的saveButton侦听器中，日志。d消息显示应包含选中项目的列表大小为零？！

请看一下代码，让我知道我遗漏了什么？

Answer 1

试试这个：这是一个带有两个片段的示例项目OneActivity：public ArrayList myBeansList\u frgnt1；public ArrayList myBeansList\u frgnt2；通过单击“保存”按钮，迭代myBeansList\u frgnt1并检查是否选择了任何项目。如果选择了项目，我会将该项目添加到myBeansList\u frgnt2。显示在片段2中。

主要活动：

public class MainActivity extends FragmentActivity {
private FragmentManager mFragmentManager;
private MyFragment1 myFragment1;
public ArrayList<MyBean> myBeansList_frgnt1;
public ArrayList<MyBean> myBeansList_frgnt2;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mFragmentManager = getSupportFragmentManager();
    myBeansList_frgnt1 = new ArrayList<MyBean>();
    myBeansList_frgnt2 = new ArrayList<MyBean>();

}

@Override
protected void onResume() {
    super.onResume();
    myFragment1 = new MyFragment1();
    FragmentTransaction mTransaction = mFragmentManager.beginTransaction();
    mTransaction.replace(R.id.framid, myFragment1, "applock").commit();
}

}

维护MyBean对象中的状态

@Override
public View getView(int position, View view, ViewGroup parent) {
    final ViewHolder holder;
    if (view == null) {
        holder = new ViewHolder();
        view = LayoutInflater.from(mContext).inflate(R.layout.list_item, null);
        holder.mTextView = (TextView) view.findViewById(R.id.textView1);
        holder.mBox = (CheckBox) view.findViewById(R.id.checkBox1);
        holder.mImageView = (ImageView) view.findViewById(R.id.imageView1);
        view.setTag(holder);

    } else {
        holder = (ViewHolder) view.getTag();
    }
    final MyBean mBean = mBeansList.get(position);

    holder.mBox.setOnCheckedChangeListener(null);
    holder.mBox.setChecked(mBean.isChecked());
    holder.mBox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
            if (isChecked) {
                mBean.setChecked(true);
            } else {
                mBean.setChecked(false);
            }
        }
    });
    // setting text and image
    holder.mTextView.setText(mBean.getmName());
    holder.mImageView.setImageResource(mBean.getmImgId());
    return view;
}
private class ViewHolder {
    TextView mTextView;
    CheckBox mBox;
    ImageView mImageView;
}

碎片1：

public class MyFragment1 extends Fragment {
private ListView mListView;
private MyBaseAdpter myBaseAdpter;
private Button mButton;

@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_layout, null);
    mListView = (ListView) view.findViewById(R.id.listviewid);
    mButton = (Button) view.findViewById(R.id.bttnid);
    return view;
}

@Override
public void onResume() {
    super.onResume();
    final MainActivity mActivity = (MainActivity) getActivity();
    myBaseAdpter = new MyBaseAdpter(mActivity.myBeansList_frgnt1, getActivity());
    mListView.setAdapter(myBaseAdpter);
    mButton.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            int size = mActivity.myBeansList_frgnt1.size();
            for (int i = 0; i < size; i++) {
                MyBean mMyBean = mActivity.myBeansList_frgnt1.get(i);
                if (mMyBean.isChecked()) {
                    mActivity.myBeansList_frgnt2.add(mMyBean);
                }
            }
        }
    });
}

}

片段2：

public class MyFragment2 extends Fragment {
private ListView mListView;
private MyBaseAdpter myBaseAdpter;

@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_layout, null);
    mListView = (ListView) view.findViewById(R.id.listviewid);
    return view;
}

@Override
public void onResume() {
    super.onResume();
    MainActivity mActivity = (MainActivity) getActivity();
    myBaseAdpter = new MyBaseAdpter(mActivity.myBeansList_frgnt2, getActivity());
    mListView.setAdapter(myBaseAdpter);
}

}

MyBean：

public class MyBean {
private String mName;
private int mImgId;
private boolean isChecked;

public String getmName() {
    return mName;
}

public void setmName(String mName) {
    this.mName = mName;
}

public int getmImgId() {
    return mImgId;
}

public void setmImgId(int mImgId) {
    this.mImgId = mImgId;
}

public boolean isChecked() {
    return isChecked;
}

public void setChecked(boolean isChecked) {
    this.isChecked = isChecked;
}

public MyBean() {
    super();
    // TODO Auto-generated constructor stub
}

}