Java 使用标记在同一活动的片段之间传输多个字符串

我很难弄清楚如何在托管在同一活动上的两个片段之间共享数据

目标： 我想将字符串从微调器的选定位置和图像url字符串从选定列表视图位置从片段a传输到片段B

尝试： 我在这里读了关于这个问题的文件 然后创建了以下接口，用于在片段和宿主活动之间使用

public interface OnSelectionListener {
public void OnSelectionListener(String img, String comments );

}

然后我继续在片段A的onCreateView方法中实现它，如下所示：

  postList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                                int position, long id) {

            ListData link = data.get(position);
            String permalink = link.getComments();
            String largeImg = link.getImageUrl();



            Fragment newFragment = new DetailsView();

            FragmentTransaction transaction = getFragmentManager().beginTransaction();

            // Replace whatever is in the fragment_container view with this fragment,
            // and add the transaction to the back stack
            transaction.replace(R.id.fragment_container, newFragment);
            transaction.addToBackStack(null);

            // Commit the transaction
            transaction.commit();

                //pass data to host activity
            selectionListener.OnSelectionListener(permalink,largeImg);


        }
    });

 @Override
public void OnSelectionListener(String img, String comments) {
    DetailsView detailsView = new DetailsView();
    DetailsView dView = (DetailsView)getSupportFragmentManager().findFragmentByTag(detailsView.getCustomTag());
    dView.setInformation(img, comments);
}

在主机活动中，我实现了我编写的接口，并覆盖了该方法，如下所示：

  postList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view,
                                int position, long id) {

            ListData link = data.get(position);
            String permalink = link.getComments();
            String largeImg = link.getImageUrl();



            Fragment newFragment = new DetailsView();

            FragmentTransaction transaction = getFragmentManager().beginTransaction();

            // Replace whatever is in the fragment_container view with this fragment,
            // and add the transaction to the back stack
            transaction.replace(R.id.fragment_container, newFragment);
            transaction.addToBackStack(null);

            // Commit the transaction
            transaction.commit();

                //pass data to host activity
            selectionListener.OnSelectionListener(permalink,largeImg);


        }
    });

 @Override
public void OnSelectionListener(String img, String comments) {
    DetailsView detailsView = new DetailsView();
    DetailsView dView = (DetailsView)getSupportFragmentManager().findFragmentByTag(detailsView.getCustomTag());
    dView.setInformation(img, comments);
}

在片段B中，我按照以下方式设置了一个“标记”

 private String tag;

public void setCustomTag(String tag)
{
    this.tag = tag;
}

public String getCustomTag()
{
    return tag;
}



@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setCustomTag("DETAILS_VIEW");

我的想法是，通过从宿主活动调用此方法，可以将信息传递给片段B

 void setInformation (String info, String img){
    RedditDetailsTask detailsTask = new RedditDetailsTask(null,DetailsView.this);
    detailsTask.execute(info);
    setDrawable(img);
}

我需要什么： 我想知道如何正确使用标记来实现这一点，我没有在xml中声明任何片段id，而是选择在片段容器中交换片段

---

我也不确定这是否是在片段之间传递多个字符串的好方法。我是一个新手程序员，所以我知道我的逻辑可能看起来很尴尬，但我正在尽我最大的努力学习如何正确地做到这一点。如果您的高级开发人员能为我指出正确的方向，我将不胜感激。

您不需要使用标签。看看这个例子。活动实现了一个接口，该接口允许您从Fragment1返回到活动，然后活动将信息中继到Fragment2

我遗漏了所有关于FragmentManager等的android内容

interface FragmentListener {

    void onTalk(String s1);

}

public class MyActivity extends Activity implements FragmentListener {

    Fragment2 fragment2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_my);
        // Find fragment2 and init
    }

    @Override
    public void onTalk(String s1) {
        fragment2.onListen(s1);
    }

    private static class Fragment1 extends Fragment {

        private FragmentListener communication;

        @Override
        public void onAttach(Activity activity) {
            super.onAttach(activity);
            communication = (FragmentListener) activity;
        }

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

        @Override
        public void onViewCreated(View view, Bundle savedInstanceState) {
            super.onViewCreated(view, savedInstanceState);
            // or in an onClick listener
            communication.onTalk("blah blah");
        }
    }

    private static class Fragment2 extends Fragment {

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

        public void onListen(String s1) {
            Log.d("TADA", s1);
        }
    }
}

---

我的方法是，当您通过OnSelectionListener接口在activity中获得回调时，我将创建Fragment B对象并按如下方式为其设置参数：

 @Override
 public void OnSelectionListener(String img, String comments) {
  DetailsView detailsView = new DetailsView();
  Bundle args=new Bundle();
  args.putString("img",img);
  args.putString("comments",comments);
  detailsView.setArguments(args);
  //code here to replace the fragment A with fragment B

  }

  @Override
 public void onCreate(Bundle savedInstanceState) {

  Bundle args=getArguments();
  String img=args.getString("img");
  String comments=args.getString("comments");
  //do whatever you want to do with the varaibles

  }

然后，在片段B的onCreate方法中，您可以按如下方式检索值：

 @Override
 public void OnSelectionListener(String img, String comments) {
  DetailsView detailsView = new DetailsView();
  Bundle args=new Bundle();
  args.putString("img",img);
  args.putString("comments",comments);
  detailsView.setArguments(args);
  //code here to replace the fragment A with fragment B

  }

  @Override
 public void onCreate(Bundle savedInstanceState) {

  Bundle args=getArguments();
  String img=args.getString("img");
  String comments=args.getString("comments");
  //do whatever you want to do with the varaibles

  }

---

您可以尝试在B片段中创建两个公共静态字符串

看起来像这样

public static String img;
public static String comment;

您可以在将事务设置为片段B之前设置变量

FragmentTransaction transaction = getFragmentManager().beginTransaction();

// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack
transaction.replace(R.id.fragment_container, newFragment);
transaction.addToBackStack(null);

SecondFragment.img = new String("imgString"); //Making a new string so incase you change the string in bfragment, the values wont change in here
SecondFragment.comment = new String("comment");

// Commit the transaction
transaction.commit();

然后在onStop（）或onDestroy（）中，根据您希望变量为null的时间，将静态变量设置为null，这样它们就不会占用内存空间

public void onDestroy(){
   super.onDestroy();
   img = null;
   comment = null;
}