找不到根据列表项位置替换详细信息片段的代码

Question

对于我的主/详细列表片段，我在尝试查找代码以根据列表项的位置替换详细片段时遇到严重问题。基于需要替换的代码（顶行），我认为顶行需要更改为其他内容。因此，根据我的代码，有谁知道该行可以替换为什么？所有相关的帮助将不胜感激。我想要实现的行为就像主细节流中的行为，如果仅在双窗格模式下，细节片段将被替换为所选列表项的片段。如果在单窗格模式下，选定的列表项将打开一个活动。

需要替换的代码（顶行）

FragmentLineChooserList newFragment = new FragmentLineChooserList();
                FragmentTransaction transaction = FragmentWCLine.this.getActivity().getSupportFragmentManager().beginTransaction();
                transaction.replace(R.id.detail_container, newFragment);
                transaction.commit();

FragmentWCLine.java

public class FragmentWCLine extends android.support.v4.app.Fragment {

    public final static String EXTRA_MESSAGE = "Station_key";

    private class WC {
        private CharSequence station;
        private CharSequence zone;
        private Class<? extends Activity> activityClass;
        private Class<? extends android.support.v4.app.Fragment> fragmentClass;

        public WC(int stationResId, int zoneResId, Class<? extends Activity> activityClass, Class<? extends android.support.v4.app.Fragment> fragmentClass) {
            this.fragmentClass = fragmentClass;
            this.activityClass = activityClass;
            this.station = getResources().getString(stationResId);
            this.zone = getResources().getString(zoneResId);
        }

        @Override
        public String toString() { return station.toString(); }
        public String getzone(){ return zone.toString(); }
    }

    private static WC[] mWC;

    /**
     * Whether or not the activity is in two-pane mode, i.e. running on a tablet
     * device.
     */
    private boolean mTwoPane;

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
        View v = inflater.inflate(R.layout.fragment_wc_line, container, false);

        // Instantiate the list of stations.
        mWC = new WC[]{
                new WC(R.string.bank, R.string.zone_1, WCBankActivity.class, FragmentWCBank.class),
                new WC(R.string.wat, R.string.zone_1, WCWATActivity.class, FragmentWCWAT.class)
        };

        final ListView listView = (ListView)v.findViewById(R.id.list_wc);
        listView.setAdapter(new MyAdapter(getActivity(), mWC));
        listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);

        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                if(mTwoPane){
                    startActivity(new Intent(getActivity(), mWC[position].fragmentClass));

                    FragmentLineChooserList newFragment = new FragmentLineChooserList();
                    FragmentTransaction transaction = FragmentWCLine.this.getActivity().getSupportFragmentManager().beginTransaction();
                    transaction.replace(R.id.detail_container, newFragment);
                    transaction.commit();

                    setItemNormal();
                    View rowView = view;
                    setItemSelected(rowView);
                }
                else{
                    Intent intent = new Intent(this, mWC[position].activityClass);

                    String station = mWC[position].station;
                    intent.putExtra(EXTRA_MESSAGE, station);

                    startActivity(intent);
                }
            }

            public void setItemSelected(View view){
                View rowView = view;
                view.setBackgroundColor(Color.parseColor("#66CCCC"));

                TextView tv0 = (TextView)rowView.findViewById(R.id.list_item_station);
                tv0.setTextColor(Color.parseColor("#000099"));

                TextView tv1 = (TextView)rowView.findViewById(R.id.list_item_zone);
                tv1.setTextColor(Color.parseColor("#000099"));
            }

            public void setItemNormal()
            {
                for (int i=0; i< listView.getChildCount(); i++) {
                    View v = listView.getChildAt(i);
                    v.setBackgroundColor(Color.TRANSPARENT);

                    TextView tv0 = ((TextView) v.findViewById(R.id.list_item_station));
                    tv0.setTextColor(Color.WHITE);

                    TextView tv1 = ((TextView) v.findViewById(R.id.list_item_zone));
                    tv1.setTextColor(Color.parseColor("#B5B5B5"));
                }
            }
        });

        return v;
    }

    static class MyAdapter extends BaseAdapter {

        static class ViewHolder {
            TextView station;
            TextView zone;
        }

        LayoutInflater inflater;
        WC[] mWC;

        public MyAdapter(Context contexts, WC[] samples) {
            this.mWC = samples;
            inflater = LayoutInflater.from(contexts);
        }

        @Override
        public int getCount() {
            return mWC.length;
        }

        @Override
        public Object getItem(int position) {
            return mWC[position];
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        /**set selected position**/
        private int selectPosition = -1;
        public void setSelectPosition(int position){
            if(position!=selectPosition){
                selectPosition = position;
            }
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder viewHolder;
            if (convertView == null) {
                convertView = inflater.inflate(R.layout.list_item_dualline, null);
                viewHolder = new ViewHolder();

                viewHolder.station = (TextView) convertView.findViewById(R.id.list_item_station);
                viewHolder.zone = (TextView) convertView.findViewById(R.id.list_item_zone);
                convertView.setTag(viewHolder);
            } else {
                viewHolder = (ViewHolder) convertView.getTag();
            }
            viewHolder.station.setText(mWC[position].station);
            viewHolder.zone.setText(mWC[position].getzone());

            //change item color
            if(position==selectPosition){
                //change item background
                convertView.setBackgroundColor(Color.parseColor("#000099"));
                //change text color
                viewHolder.station.setTextColor(Color.parseColor("#000099"));
            }else {

            }

            return convertView;
        }
    }
}

WCBankActivity

public class WCBankActivity extends ActionBarActivity {

    public final static String EXTRA_MESSAGE = "Station_key";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fragment_wc_bank);

        if (savedInstanceState == null) {
            // Get the message from the intent
            Intent intent = getIntent();
            // Notice to specify the sender Activity for the message
            String station = intent.getStringExtra(WCBankActivity.EXTRA_MESSAGE);

            FragmentWCBank newFragment = new FragmentWCBank();
            FragmentTransaction transaction = this.getSupportFragmentManager().beginTransaction()‌​
            transaction.replace(R.id.detail_container, newFragment);
            transaction.commit();
        }
    }
}

FragmentWCBank

public class FragmentWCBank extends android.support.v4.app.Fragment {

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.fragment_wc_bank, container, false);

        return v;
    }

}

错误

Answer 1

我想我现在理解得更好了。你真正想要的是......开始另一个活动并立即启动预期的片段，这对其他人来说会更清楚。为了在另一个活动中显示正确的片段，您应该在该活动中进行。有一个很好的谷歌网页@Starting Another Activity。以下是该网页的代码示例，使用您发布的代码。

代码示例：

WCBankActivity.java：

// Define this for Intent, mainly keep the key consistent between 2 activities
public final String EXTRA_MESSAGE = "Station_key";

FragmentWCLine.java：

if (mTwoPane) {
   ...
}
else {
   Intent intent = new Intent(this, mWC[position].activityClass);

   String station = mWC[position].station;
   intent.putExtra(WCBankActivity.EXTRA_MESSAGE, station);

   startActivity(intent);
}

在另一个活动中，WCWATActivity.java，如果我理解正确的话：

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

   if (savedInstanceState == null) {
       // Get the message from the intent
       Intent intent = getIntent();
       // Notice to specify the sender Activity for the message
       String station = intent.getStringExtra(WCBankActivity.EXTRA_MESSAGE);
       ...
       FragmentLineChooserList newFragment = new FragmentLineChooserList();
       FragmentTransaction transaction = getActivity().getSupportFragmentManager().beginTransaction();
       transaction.replace(R.id.detail_container, newFragment);
       transaction.commit();
   }
}

注意事项：

1. 注意从一个活动到另一个活动的键字符串EXTRA_MESSAGE。在 WCBankActivity 类中定义这个常量。
2. 在onCreate() 中，以消息的形式获取电台，并对其进行处理。
3. 这是一种将数据从一个 Activity 传递到另一个 Activity 的技术，Intent.putExtra() 和 getStringExtra()。
4. 使用getActivity().getSupportFragmentManager() 代替 FragmentWCLine.getActivity()。

Answer 2

现在，我看到变量 mTwoPane 永远不会改变。关于您的问题，代码FragmentTransaction transaction = FragmentWCLine 和与之相关的代码对我来说很好。

您的最高代码FragmentTransaction transaction = FragmentMainList。这可能不正确，需要代码：

FragmentTransaction transaction = FragmentWCLine

注意：

• FragmentWCLine 是正确的，而不是 FragmentMainList。

建议的代码，更简洁：

FragmentTransaction transaction = this.getActivity().getSupportFragmentManager().beginTransaction();

注意：在 Fragment 中时，getActivity() 应该是有效的。这样您就无需指定代码所在的片段类。