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我想共享主活动和我的列表片段之间的字符串。所以我想我可以使用Shared.Preferences。由于我刚刚接触android,刚开始使用共享首选项,所以我面临这个问题。ListFragments中的共享首选项
这是我的共享优先级
public class AppPrefs {
private static final String USER_PREFS = "USER_PREFS";
private SharedPreferences appSharedPrefs;
private SharedPreferences.Editor prefsEditor;
private String responseXml = "response_xml_prefs";
public AppPrefs(Context context){
this.appSharedPrefs = context.getSharedPreferences(USER_PREFS, Activity.MODE_PRIVATE);
this.prefsEditor = appSharedPrefs.edit();
}
public String getResponse_xml() {
return appSharedPrefs.getString(responseXml, "unknown");
}
public void setResponse_xml(String _responser_xml) {
prefsEditor.putString(responseXml, _responser_xml).commit();
}
}
这在我mainActivity
Context context = getApplicationContext();
AppPrefs appPrefs = new AppPrefs(context);
appPrefs.setResponse_xml(responseXml);
,这在我的ListFragment
Context context = this.getActivity();
AppPrefs appPrefs = new AppPrefs(context);
String responseXml = appPrefs.getResponse_xml();
但是当我做Log.e("responseXml", responseXml);
m得到默认字符串“未知”,这是我在共享喜好类中输入的。 请让我知道我在哪里出了错:(
更新1
public class TabActivity extends Activity {
MyTask myNewTask;
String responseXml;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent in = getIntent();
String requestXml=in.getStringExtra("xml");
myNewTask = new MyTask(requestXml);
myNewTask.setOnResultListener(asynResult);
myNewTask.execute();
ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
actionBar.setDisplayShowTitleEnabled(true);
/** Creating All Tab */
Tab tab = actionBar.newTab()
.setText("All")
.setTabListener(new CustomTabListener<AllMsgFragment>(this, "All", AllMsgFragment.class,responseXml));
//.setIcon(R.drawable.android);
actionBar.addTab(tab);
/** Creating Success Tab */
tab = actionBar.newTab()
.setText("Success")
.setTabListener(new CustomTabListener<SuccessMsgFragment>(this, "Success", SuccessMsgFragment.class,responseXml));
//.setIcon(R.drawable.apple);
我唐诺如何通过捆绑
}
OnAsyncResult asynResult = new OnAsyncResult() {
@Override
public void onResultSuccess(final int resultCode, final String responseXml) {
runOnUiThread(new Runnable() {
public void run() {
storeData(responseXml);
}
});
}
@Override
public void onResultFail(final int resultCode, final String errorMessage) {
runOnUiThread(new Runnable() {
public void run() {
}
});
}
};
void storeData(String responseXml){
//this.responseXml=responseXml;
/*Context context = getApplicationContext();
AppPrefs appPrefs = new AppPrefs(context);
appPrefs.setResponse_xml(responseXml);*/
Fragment fragment = new Fragment();
Bundle bundle = new Bundle();
bundle.putString("responseXml", responseXml);
fragment.setArguments(bundle);
}
}
其显示空指针异常
编辑2
使用一个静态变量,解决了我的问题
'SharedPreferences'存储为单例。只要它在你的应用程序的范围内,任何'Context'都是有效的。你使用'Bundle'将数据传递给Fragment的建议是正确的。但是,我不明白为什么OP的方法不起作用。 – Vikram
我已经更新了代码。我尝试使用Bundle。并在我的ListFragment,(onCreateView)我有doneBundle束= this.getArguments(); String myString = bundle.getString(“responseXml”,“unknown”);不是得到一个例外:nullpointer – user1743673
谢谢user2558882,我编辑了答案。 – malimo