android - 非字符串类型的默认 bindPreferenceSummaryToValue 崩溃

Question

我正在按照示例方法添加找到的兼容首选项/fragment 对话框 here .这样做时，我发现如果我的首选项是整数、 bool 值等，它就会崩溃。

private static void bindPreferenceSummaryToValue(Preference preference) {
    // Set the listener to watch for value changes.
    preference
            .setOnPreferenceChangeListener(sBindPreferenceSummaryToValueListener);

    // Trigger the listener immediately with the preference's
    // current value.
    sBindPreferenceSummaryToValueListener.onPreferenceChange(
            preference,
            PreferenceManager.getDefaultSharedPreferences(
                    preference.getContext()).getString(preference.getKey(),""));
}

我发现我可以通过将 getString() 更改为 getInteger() 并根据类型使用不同的 bindPreferenceSummaryToValue 函数来为 Integer 工作是。当然，这似乎是一个非常不优雅的解决方案，但我正在努力弄清楚我还能做些什么。这是堆栈跟踪，顺便说一句。

11-22 19:52:10.068: E/AndroidRuntime(17564): FATAL EXCEPTION: main
11-22 19:52:10.068: E/AndroidRuntime(17564): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.kd7uiy.hamfinder/com.kd7uiy.hamfinder.MainSettingsActivity}: java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String
11-22 19:52:10.068: E/AndroidRuntime(17564):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at android.app.ActivityThread.access$600(ActivityThread.java:141)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at android.os.Handler.dispatchMessage(Handler.java:99)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at android.os.Looper.loop(Looper.java:137)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at android.app.ActivityThread.main(ActivityThread.java:5103)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at java.lang.reflect.Method.invokeNative(Native Method)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at java.lang.reflect.Method.invoke(Method.java:525)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at dalvik.system.NativeStart.main(Native Method)
11-22 19:52:10.068: E/AndroidRuntime(17564): Caused by: java.lang.ClassCastException: java.lang.Integer cannot be cast to java.lang.String
11-22 19:52:10.068: E/AndroidRuntime(17564):    at android.app.SharedPreferencesImpl.getString(SharedPreferencesImpl.java:224)
11-22 19:52:10.068: E/AndroidRuntime(17564):    at com.kd7uiy.hamfinder.MainSettingsActivity.bindPreferenceSummaryToValue(MainSettingsActivity.java:194)

Answer 1

我找不到一个干净的解决方案，但最好的解决方法似乎是这样的，使用 instanceof 来确定您正在处理的数据类型。

private static void bindPreferenceSummaryToValue(Preference preference) {
    // Set the listener to watch for value changes.
    preference
            .setOnPreferenceChangeListener(sBindPreferenceSummaryToValueListener);


    if (preference instanceof SeekBarPreference)
    {
        // Trigger the listener immediately with the preference's
        // current value.
        sBindPreferenceSummaryToValueListener.onPreferenceChange(
                preference,
                PreferenceManager.getDefaultSharedPreferences(
                        preference.getContext()).getInt(preference.getKey(),0));
    }
    else if (preference instanceof CheckBoxPreference)
    {
        // Trigger the listener immediately with the preference's
        // current value.
        sBindPreferenceSummaryToValueListener.onPreferenceChange(
                preference,
                PreferenceManager.getDefaultSharedPreferences(
                        preference.getContext()).getBoolean(preference.getKey(),true));
    }
}