0

我正在开发一个使用“SharedPreferences”允许用户从语言环境列表中选择语言环境的应用程序设置活动的 android 项目。

当我使用“ listPreferences.setvalue() ”根据当前区域设置设置默认选定值时，会创建两次 SettingsActivity！

以下是我的代码：

private void setLanguagePrefDefaultValues() {
    // Current Locale
    Locale sysLocale = getResources().getConfiguration().locale;
    // Language Preference
    ListPreference languagePref = (ListPreference) findPreference(getString(R.string.pref_language_key));
    // Edit Preference Summary
    languagePref.setSummary(sysLocale.getDisplayName(sysLocale));

    // Set Language Preference to Current Locale
    if (sysLocale.getCountry() != "") {
        languagePref.setValue(sysLocale.getLanguage() + "_" + sysLocale.getCountry());

    } else {
        languagePref.setValue(sysLocale.getLanguage());
    }
}

这个方法是从onCreate()方法调用的

我注意到，当调用“ setSummary(...) ”方法时没有问题，但是当调用“ setValue() ”时会出现问题

设置活动类：

import java.util.Locale;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.res.Configuration;
import android.os.Bundle;
import android.preference.ListPreference;
import android.preference.Preference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceCategory;
import android.view.View;
import android.view.Window;
import android.widget.TextView;
import com.telephoenic.simgateway.R;

/**
* Settings Activity
* 
* @author Abd Alrahman Shoman
* @since September 2013
* @version 1.0.0
* 
*/
public class SettingsActivity extends PreferenceActivity implements
    SharedPreferences.OnSharedPreferenceChangeListener {

public static boolean updatedLocale = false;

@Override
public void onCreate(Bundle savedInstanceState) {
    requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.xml.settings_pref_file);
    getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE,
            R.layout.custom_title_bar);

    TextView title = (TextView) findViewById(R.id.textView_titleBar_title);
    title.setText(getResources()
            .getString(R.string.title_activity_settings));

    getPreferenceScreen().getSharedPreferences()
            .registerOnSharedPreferenceChangeListener(this);

    hideFirstLaunchPref();
    setLanguagePrefDefaultValues();
    setProfileEditPrefIntent();

}

@Override
protected void onStop() {
    super.onStop();
    getPreferenceScreen().getSharedPreferences()
            .unregisterOnSharedPreferenceChangeListener(this);
}

@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
        String key) {
    if (key.equals(getString(R.string.pref_language_key))) {
        Locale locale = null;
        String languageCode =     sharedPreferences.getString(getString(R.string.pref_language_key), "");
        if (languageCode.length() > 2) {
            char ch3 = languageCode.charAt(2);
            if (ch3 == '_') {
                String language = languageCode.substring(0, 2);
                String country = languageCode.substring(3, 5);
                locale = new Locale(language, country);
            }
        } else {
            locale = new Locale(languageCode);
        }

        Configuration config = new Configuration();
        config.locale = locale;
        getApplicationContext().getResources().updateConfiguration(config,
                getBaseContext().getResources().getDisplayMetrics());
        refresh();
        updatedLocale = true;
    }
}

/**
 * Hide FirstLaunchPref from preference screen
 * 
 */
private void hideFirstLaunchPref() {
    // First Launch Preference
    PreferenceCategory firstlaunchPref = (PreferenceCategory) findPreference(getString(R.string.pref_app_first_launch));
    // Hide First Launch Preference
    getPreferenceScreen().removePreference(firstlaunchPref);
}

/**
 * Set LanguagePref default Values (summary, selected language)
 * 
 */
private void setLanguagePrefDefaultValues() {
    // Current Locale
    Locale sysLocale = getResources().getConfiguration().locale;
    // Language Preference
    ListPreference languagePref = (ListPreference)   findPreference(getString(R.string.pref_language_key));
    // Edit Preference Summary
    languagePref.setSummary(sysLocale.getDisplayName(sysLocale));

    // Set Language Preference to Current Locale
    if (sysLocale.getCountry() != "") {
        languagePref.setValue(sysLocale.getLanguage() + "_" + sysLocale.getCountry());

    } else {
        languagePref.setValue(sysLocale.getLanguage());
    }
}

/**
 * Set ProfileEditPref Intent
 * 
 */
private void setProfileEditPrefIntent() {
    // Start PoS Profile Activity onClick
    Preference profile = (Preference) findPreference(getString(R.string.pref_profile_edit_key));
    profile.setIntent(new Intent(SettingsActivity.this,
            PosProfileActivity.class));
}

/**
 * Restart activity to reflect locale change
 * 
 */
private void refresh() {
    Intent intent = getIntent();
    overridePendingTransition(0, 0);
    intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
    finish();

    overridePendingTransition(0, 0);
    startActivity(intent);
}

/**
 * Back to previous activity
 * 
 * @param View
 *            v
 */
public void back(View v) {
    finish();
}

}

4

1 回答 1

0

尝试注释掉您的 refresh() 方法。

当您进入 SettingsActivity 时将调用 onSharedPreferenceChanged。

此外，我认为不需要这种 refresh() 方法。

如果这不起作用，我会更多地研究它。

一定是这个原因。。又看了一遍：

@Override
public void onSharedPreferenceChanged(SharedPreferences sharedPreferences,
    String key) {
    if (key.equals(getString(R.string.pref_language_key))) {
       ... // this is called when setLanguagePrefDefaultValues() sets value
       refresh()
    }
}

private void refresh() {
    // start a new SettingsActivity, why you do this in the first place, I do not know 

    Intent intent = getIntent();
    overridePendingTransition(0, 0);
    intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
    finish();

    overridePendingTransition(0, 0);
    startActivity(intent);
}

尝试将刷新方法重写为：

private void refresh() {
    // ok it is to reflect the language update, i see :)

    Intent intent = getIntent();
    overridePendingTransition(0, 0);
    intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION | Intent.FLAG_ACTIVITY_NO_HISTORY);
    startActivity(intent);
    finish();

}

否则请参阅：[从历史堆栈中删除活动

[1]：从历史堆栈中删除一个活动以获得更多选项以从后台堆栈中删除当前活动。

于 2013-09-29T15:07:41.723 回答