Reading SharedPreferences data in Fragment, within FragmentActivity

问题

I'm trying to save the name the user enters on the log in screen below Settings.java to a sharedPreference, which will be read by TestFragment2.java, which is called from another FragmentActivity, SampleTabsDefault.java

Settings.java

    private void savePrefs(String key, boolean value) {
        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
        Editor edit = sp.edit();
        edit.putBoolean(key, value);
        edit.commit();
    }

    private void savePrefs(String key, String value) {
        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
        Editor edit = sp.edit();
        edit.putString(key, value);
        edit.commit();
    }

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        savePrefs("CHECKBOX", cb.isChecked());
        if (cb.isChecked())
            savePrefs("NAME", et.getText().toString());
        Intent myIntent = new Intent("com.test.SAMPLETABSDEFAULT");
        startActivity(myIntent);

        finish();
    }

}

Intent myIntent = new Intent("com.test.SAMPLETABSDEFAULT");startActivity(myIntent); loads the SampleTabsDefault.java just fine, and so do all the fragments it calls.

 class NavTabs extends FragmentPagerAdapter {
    public NavTabs(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        switch(position)
        {
                case 0:
                     TestFragment fragment = new TestFragment();  
                     return fragment;

                 case 1:
                     TestFragment2 fragment2 = new TestFragment2();  
                     return fragment2;

          }

                     TestFragment3 fragment3 = new TestFragment3();  
                     return fragment3;


    }

I can scroll left right and get to fragment TestFragment2.java seen below....however its not reading, or Im making a very bonehead move applying the sharedPreferences inside TestFragment2.java

TestFragment2.java

 @Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
    View myView = inflater.inflate(R.layout.fragment_2, container, false);
     text = (TextView)myView.findViewById(R.id.textView1);
     et = (TextView)myView.findViewById(R.id.textView3);
     cb = (CheckBox) myView.findViewById(R.id.checkBox1);


    loadPrefs();
    return myView;

}

private void loadPrefs() {
    SharedPreferences sp = getActivity().getSharedPreferences("CHECKBOX", 0);
    boolean cbValue = sp.getBoolean("CHECKBOX", false);
    String name = sp.getString("NAME", "YourName");
    if(cbValue){
        cb.setChecked(true);
    }else{
        cb.setChecked(false);
    }
    et.setText(name);
}

In TestFragment2.java Im trying to read and apply to textView via 'setText();' the sharedPreferences the same way I do on Settings.java. The code in Settings.java does work, String name = sp.getString("NAME", "YourName");it loads the sharedPreference and displays the name entered by the user last time application was ran , but in TestFragmnet2.java the same block of code returns YourName from String name = sp.getString("NAME", "YourName");

Any help is greatly appreciated, thanks!!

回答1:

I think that you are calling

SharedPreferences sp = getActivity().getSharedPreferences("CHECKBOX", 0);

incorrectly in TestFragment2's loadPrefs() ,method

From the docs the first param (name) is:

Desired preferences file. If a preferences file by this name does not exist, it will be created when you retrieve an editor (SharedPreferences.edit()) and then commit changes (Editor.commit()).

So it looks like you are creating a new prefernces file called "CHECKBOX" in TestFragment2.

maybe change loadPrefs() to the same usage found in Settings.java so you can call up the same preferences used earlier like so:

private void loadPrefs() {
    SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity())
    boolean cbValue = sp.getBoolean("CHECKBOX", false);
    String name = sp.getString("NAME", "YourName");
    if(cbValue){
        cb.setChecked(true);
    }else{
        cb.setChecked(false);
    }
    et.setText(name);

}

来源：https://stackoverflow.com/questions/15031825/reading-sharedpreferences-data-in-fragment-within-fragmentactivity