android - SharedPreferences 奇怪的警告

Question

我使用 SharedPreferences，有时我会在 logcat 中收到此警告:

08-27 11:46:55.453: W/SharedPreferencesImpl(21824): getSharedPreferences
08-27 11:46:55.453: W/SharedPreferencesImpl(21824): org.xmlpull.v1.XmlPullParserException: Map value without name attribute: string
08-27 11:46:55.453: W/SharedPreferencesImpl(21824):     at com.android.internal.util.XmlUtils.readThisMapXml(XmlUtils.java:568)
08-27 11:46:55.453: W/SharedPreferencesImpl(21824):     at com.android.internal.util.XmlUtils.readThisValueXml(XmlUtils.java:821)
08-27 11:46:55.453: W/SharedPreferencesImpl(21824):     at com.android.internal.util.XmlUtils.readValueXml(XmlUtils.java:755)
08-27 11:46:55.453: W/SharedPreferencesImpl(21824):     at com.android.internal.util.XmlUtils.readMapXml(XmlUtils.java:494)
08-27 11:46:55.453: W/SharedPreferencesImpl(21824):     at android.app.SharedPreferencesImpl.loadFromDiskLocked(SharedPreferencesImpl.java:113)
08-27 11:46:55.453: W/SharedPreferencesImpl(21824):     at android.app.SharedPreferencesImpl.access$000(SharedPreferencesImpl.java:48)
08-27 11:46:55.453: W/SharedPreferencesImpl(21824):     at android.app.SharedPreferencesImpl$1.run(SharedPreferencesImpl.java:87)

它适用于大多数情况，但测试人员表示有时他们会遇到问题。有时加载回来根本不起作用。这是我的 SharedPreffer 类:

public class SharedPreffer {

    String PREF_FILE_NAME = "saveFile";

    public SharedPreffer(Context context) {
        this.context = context;
    }

    Context context;
    public static final String DEFAULT_VALUE = "";

    public void savePreferences(String key, int value) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(
                PREF_FILE_NAME, 0);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, Integer.toString(value));
        editor.commit();
    }

    public void savePreferences(String key, String value) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(
                PREF_FILE_NAME, 0);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, value);
        editor.commit();
    }

    public void savePreferences(String key, Boolean value) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(
                PREF_FILE_NAME, 0);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, Boolean.toString(value));
        editor.commit();
    }


    public String loadPreferences(String key) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(PREF_FILE_NAME, 0);

        return sharedPreferences.getString(key, DEFAULT_VALUE);

    }

}

谁能给我一些关于这方面的提示？

Answer 1

Map value without name attribute: string 表明您的 String key 为 null 或空。

在方法的开头检查这种情况，如果出现问题则抛出异常，您将从哪里看到传递此类无效键的位置:

if (key == null || key.equals("")) throw new IllegalArgumentException("Key can't be null or empty string");