Java 使用值从片段B返回片段A

我知道有很多关于这方面的线索，但我似乎真的不明白如何去解决它。。我主要尝试的是在片段B中单击按钮之后，我想返回到片段A以及id值。。
因此，在我的后退中，你转到片段A，这将引导你到片段B，当按下一个按钮时，我想回到片段A，并显示一个值。这是片段B中的onClick侦听器：

//Fragment B which i called from Fragment A
addButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if(value.getText().toString().trim().length() != 0) {
                 String order = value.getText().toString(); //The value i want in Fragment B
                 //return to Fragment A
            }
}

在我的主要活动中，我像这样踩着我的碎片：

//fragmentManager is initialized in onCreate()
...
private void selectItem(int position) {

    Fragment fragment = null;
    String fTag = null;

    switch (position) {
        case 0:
            fragment = new FragmentA();
            fTag = "fragmentA";
            break;
        case 1:
            fragment = new FragmentC();
            fTag = "fragmentC";
            break;
        case 2:
            fragment = new FragmentD();
            fTag = "fragmentD";
            break;

        default:
            break;
    }

    if (fragment != null) {
        if(replaceFragments(fragment, fTag)) {
            mDrawerList.setItemChecked(position, true);
            mDrawerList.setSelection(position);
            setTitle(mNavigationDrawerItemTitles[position]);
            mDrawerLayout.closeDrawer(mDrawerList);
        }
    } else {
        Log.e(LOGTAG, "Error in creating fragment");
    }
}

public boolean replaceFragments(Fragment fragment, String fTag) {
    fragmentManager.beginTransaction().replace(R.id.content_frame, fragment, fTag).addToBackStack(fTag).commit();
    return true;
}

@Override
public void onBackPressed() {
    int count = fragmentManager.getBackStackEntryCount();
    if (count == 0) {
        super.onBackPressed();
    } else {
        getSupportFragmentManager().popBackStack();
        //TODO: add app title on count == 1
    }
}

 @Override 
    public void onClick(View view) {
        if(value.getText().toString().trim().length() != 0) { 
             String order = value.getText().toString(); //The value i want in Fragment B
             //return to Fragment A 

            FragmentA fragment = new FragmentA();
            Bundle args=new Bundle();
            args.putString(order);
           fragment.setArguments(args);
           getFragmentManager().beginTransaction().replace((R.id.content_frame,fragment).commit();


        } 

---

创建接口ValueChangeListener.java

public interface ValueChangeListener {

    public void onValueChanged(String value);
}

通过接口传递值：

public class FragmentB extends Fragment {

    private ValueChangeListener valueChangeListener;

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);
        try {
            valueChangeListener = (ValueChangeListener) activity;
        } catch (ClassCastException e) {
            throw new ClassCastException(activity.toString() + " must implement ValueChangeListener");
        }
    }

    //your code
    addButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            if(value.getText().toString().trim().length() != 0) {
                 String order = value.getText().toString();
                 //now the value is in the Activity and you can pass it anywhere you want from there
                 valueChangeListener.onValueChanged(order);
            }
    }

}

实现活动的接口：

public class YourActivity extends FragmentActivity implements ValueChangeListener{

    @Override
    public void onValueChanged(String value) {
    //your value is here
    }
}

---

您的onclick方法应该如下所示：

//fragmentManager is initialized in onCreate()
...
private void selectItem(int position) {

    Fragment fragment = null;
    String fTag = null;

    switch (position) {
        case 0:
            fragment = new FragmentA();
            fTag = "fragmentA";
            break;
        case 1:
            fragment = new FragmentC();
            fTag = "fragmentC";
            break;
        case 2:
            fragment = new FragmentD();
            fTag = "fragmentD";
            break;

        default:
            break;
    }

    if (fragment != null) {
        if(replaceFragments(fragment, fTag)) {
            mDrawerList.setItemChecked(position, true);
            mDrawerList.setSelection(position);
            setTitle(mNavigationDrawerItemTitles[position]);
            mDrawerLayout.closeDrawer(mDrawerList);
        }
    } else {
        Log.e(LOGTAG, "Error in creating fragment");
    }
}

public boolean replaceFragments(Fragment fragment, String fTag) {
    fragmentManager.beginTransaction().replace(R.id.content_frame, fragment, fTag).addToBackStack(fTag).commit();
    return true;
}

@Override
public void onBackPressed() {
    int count = fragmentManager.getBackStackEntryCount();
    if (count == 0) {
        super.onBackPressed();
    } else {
        getSupportFragmentManager().popBackStack();
        //TODO: add app title on count == 1
    }
}

 @Override 
    public void onClick(View view) {
        if(value.getText().toString().trim().length() != 0) { 
             String order = value.getText().toString(); //The value i want in Fragment B
             //return to Fragment A 

            FragmentA fragment = new FragmentA();
            Bundle args=new Bundle();
            args.putString(order);
           fragment.setArguments(args);
           getFragmentManager().beginTransaction().replace((R.id.content_frame,fragment).commit();


        } 

然后从碎片A中，您可以通过以下方式恢复价值：

getArguments();

---

谢谢。这是有道理的。你能告诉我，当我在活动中收到值时，如何正确地调用片段A吗？我的意思是，最好从backbackback调用它/从tag获取它？啊哈，当然！我不知道为什么我没有想到那件事。。当您可以这样设置参数时，为什么接口方法如此常见？使用接口，您可以将值发送到活动。如果这不是你想要的，那么你可以使用上面的方法将你的值直接发送到另一个片段。既然fragmentManager生活在活动中，我想我还是走那条路吧？但实际上我在某个地方看到，不建议在片段之间直接发送？快速阅读，你可能会发现一些东西：尽管它从未说明原因……也许其他人可以对此有所了解。