Question

在我的应用的设置页面中有两个EditTextPreference（s）当我更改值时，必须更新摘要。现在，只要我在EditTextPreference（s）中输入值并点击确定，它就会立即更新摘要。但是当我重新启动应用程序时，摘要会更改回默认值。但是新值保留在EditTextPreference（我打开它时可以看到）。当我在EditTextPreference中输入新值时，摘要会再次更新。如何每次从用户输入更新摘要？

这是我的代码：

SettingActivity.java

public class SettingsActivity extends AppCompatActivity {


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Display the fragment as the main content.
    getFragmentManager().beginTransaction()
            .replace(android.R.id.content, new SettingsFragment()).commit();

    setTitle("Settings");
    ActionBar actionBar=getSupportActionBar();
    // Show the Up button in the action bar.
    actionBar.setDisplayHomeAsUpEnabled(true);
}



public static class SettingsFragment extends PreferenceFragment implements SharedPreferences.OnSharedPreferenceChangeListener {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Load the preferences from an XML resource
        addPreferencesFromResource(R.xml.settings_layout);
        setHasOptionsMenu(true);

    }

    @Override
    public void onResume() {
        super.onResume();
        getPreferenceScreen().getSharedPreferences()
                .registerOnSharedPreferenceChangeListener(this);

    }

    @Override
    public void onPause() {
        super.onPause();
        getPreferenceScreen().getSharedPreferences()
                .unregisterOnSharedPreferenceChangeListener(this);

    }

    @Override
    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
        Preference pref = findPreference(key);
        if (pref instanceof EditTextPreference) {
            EditTextPreference listPref = (EditTextPreference) pref;
            pref.setSummary(listPref.getText());
        }
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        int id = item.getItemId();
        if (id == android.R.id.home) {
            startActivity(new Intent(getActivity(), HomeActivity.class));
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}
}

settings_layout.xml

 <EditTextPreference
        android:capitalize="words"
        android:dependency="email_switch"
        android:defaultValue="@string/default_email_address"
        android:key="example_text"
        android:summary="@string/pref_description_email"
        android:maxLines="1"
        android:selectAllOnFocus="true"
        android:singleLine="true"
        android:title="@string/pref_email_address_text_title"
        android:inputType="textWebEmailAddress" />
 <EditTextPreference
        android:capitalize="words"
        android:dependency="sms_switch"
        android:defaultValue="@string/default_mobile_number"
        android:key="example_text1"
        android:summary="@string/pref_description_sms"
        android:maxLines="1"
        android:selectAllOnFocus="true"
        android:singleLine="true"
        android:title="@string/pref_mobile_number_text_title"
        android:inputType="phone"/>

P.S。我在我的MAIN活动中将其称为

PreferenceManager.setDefaultValues(this, R.xml.settings_layout, false);

Answer 1

在onCreate()课程的SettingsFragment方法中，您需要获得对SharedPreferences的引用，然后运行onSharedPreferenceChanged()方法。您的onCreate()应如下所示：

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // Load the preferences from an XML resource
    addPreferencesFromResource(R.xml.settings_layout);
    setHasOptionsMenu(true);

    //if you are using default SharedPreferences
    SharedPreferences sharedPrefs = PreferenceManager.getDefaultSharedPreferences(getContext());

    onSharedPreferenceChanged(sharedPrefs, getString(R.string.key1));
    onSharedPreferenceChanged(sharedPrefs, getString(R.string.key2));

}

key1和key2是您的偏好键（在您的情况下为example_text和example_text1）保存到strings文件中。我自己做这个没有字符串引用的问题，这就是为什么我建议提取它们。

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