将字符串从活动发送到片段

Question

我尝试将字符串从活动传递到片段。如您所见，我正在使用if语句来防止应用程序崩溃。Toast 消息始终显示“捆绑空”。如何防止联邦为空？活动：public class SettingsActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    getSupportFragmentManager().beginTransaction()            .replace(android.R.id.content, new SetttingsFragment())            .commit();    Bundle bundle = new Bundle();    bundleSettings.putString("my_bundle_key", "Bundle");         SetttingsFragment setttingsFragment = new SetttingsFragment();    setttingsFragment.setArguments(bundle);片段：public class SetttingsFragment extends PreferenceFragmentCompat  {@Overridepublic void onCreatePreferences(Bundle bundle, String rootKey) {    setPreferencesFromResource(R.xml.preferences, rootKey);    Bundle bundle = getArguments();    if(bundle != null){        String bundleString = bundle.getString("my_bundle_key");        Log.i("my_bundle_key", bundleString);               } else{        Toast.makeText(getActivity(), "Bundle null", Toast.LENGTH_LONG).show();    }

Answer 1

在代码中，您将捆绑包设置为未使用的片段变量

1. 创建捆绑包

2. 创建片段

3. 在片段中设置捆绑包

4. 显示片段

这是您需要以片段形式传递参数的方式

public class SettingsActivity extends AppCompatActivity {

@Override

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    SettingsFragment settingsFragment = new SettingsFragment();

    if (savedInstanceState == null) {

        Bundle bundle = new Bundle();

        bundle.putString("my_bundle_key", "Bundle");     

        settingsFragment.setArguments(bundle);

    }

    else {

        settingsFragment.setArguments(savedInstanceState);

    }

    getSupportFragmentManager().beginTransaction()

        .replace(android.R.id.content, settingsFragment)

        .commit();

Answer 2

在调用之前，您必须调用捆绑包，如下所示：fragment

Bundle bundle = new Bundle();
        bundleSettings.putString("my_bundle_key", "Bundle");     
        SetttingsFragment setttingsFragment = new SetttingsFragment();
        setttingsFragment.setArguments(bundle);

    getSupportFragmentManager().beginTransaction()
                .replace(android.R.id.content, setttingsFragment)
                .commit();

Answer 3

在您的活动中，您正在创建两个片段对象，您正在执行的第二个对象未附加到视图且未在使用中。您的片段应按如下方式附加到视图：setargument

Bundle bundle = new Bundle();
bundleSettings.putString("my_bundle_key", "Bundle");     
SetttingsFragment setttingsFragment = new SetttingsFragment();
setttingsFragment.setArguments(bundle);

  getSupportFragmentManager().beginTransaction()
        .replace(android.R.id.content, setttingsFragment)
        .commit();

Answer 4

From Activity you send data with intent as:

Bundle bundle = new Bundle();

bundle.putString("edttext", "From Activity");

Fragmentclass obj = new Fragmentclass();

obj .setArguments(bundle);

在片段创建视图方法中：

@Override

public View onCreateView(LayoutInflater inflater, ViewGroup container,

    Bundle savedInstanceState) {

 String strtext = getArguments().getString("edttext");    

 return inflater.inflate(R.layout.fragment, container, false);

}

Answer 5

活动

AbcFragment fragment = AbcFragment .newInstance(**Value**);

               getSupportFragmentManager.beginTransaction()

                        .replace(R.id.layout_container, fragment)

                        .commit();

在片段中

public static AbcFragment newInstance(String Value) {

        Bundle args = new Bundle();

        args.putString("Value", Value);

        AbcFragment fragment = new AbcFragment ();

        fragment.setArguments(args);

        return fragment;

    }