java 奇怪的异常：使用 getBoolean 时无法将 String 转换为 Boolean
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Weird exception: Cannot cast String to Boolean when using getBoolean
提问by La bla bla
I'm getting a very weird error.
I have 2 activities. On both I'm getting the SharedPreferencesusing MODE_PRIVATE(if it matters) by sp = getPreferences(MODE_PRIVATE);on each activity's onCreate()I'm calling sp.getBoolean(IntroActivity.SHOW_INTRO, true)
我收到一个非常奇怪的错误。我有2个活动。在
我正在调用的每个活动上，我都在SharedPreferences使用MODE_PRIVATE（如果重要的话）sp = getPreferences(MODE_PRIVATE);onCreate()sp.getBoolean(IntroActivity.SHOW_INTRO, true)
On the IntroActivitythis works fine. But when I'm trying in the main activity, I'm getting this
在IntroActivity这工作正常。但是当我尝试主要活动时，我得到了这个
10-12 04:55:23.208: E/AndroidRuntime(11668): FATAL EXCEPTION: main
10-12 04:55:23.208: E/AndroidRuntime(11668): java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Boolean
10-12 04:55:23.208: E/AndroidRuntime(11668): at android.app.SharedPreferencesImpl.getBoolean(SharedPreferencesImpl.java:242)
10-12 04:55:23.208: E/AndroidRuntime(11668): at com.lablabla.parkme.ParkMeActivity.onClick(ParkMeActivity.java:194)
10-12 04:55:23.208: E/AndroidRuntime(11668): at android.view.View.performClick(View.java:4084)
10-12 04:55:23.208: E/AndroidRuntime(11668): at android.view.View$PerformClick.run(View.java:16966)
10-12 04:55:23.208: E/AndroidRuntime(11668): at android.os.Handler.handleCallback(Handler.java:615)
10-12 04:55:23.208: E/AndroidRuntime(11668): at android.os.Handler.dispatchMessage(Handler.java:92)
10-12 04:55:23.208: E/AndroidRuntime(11668): at android.os.Looper.loop(Looper.java:137)
10-12 04:55:23.208: E/AndroidRuntime(11668): at android.app.ActivityThread.main(ActivityThread.java:4745)
10-12 04:55:23.208: E/AndroidRuntime(11668): at java.lang.reflect.Method.invokeNative(Native Method)
10-12 04:55:23.208: E/AndroidRuntime(11668): at java.lang.reflect.Method.invoke(Method.java:511)
10-12 04:55:23.208: E/AndroidRuntime(11668): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
10-12 04:55:23.208: E/AndroidRuntime(11668): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
10-12 04:55:23.208: E/AndroidRuntime(11668): at dalvik.system.NativeStart.main(Native Method)
I made sure that I'm not putting a Stringsomewhere in the middle with that same key
我确保我没有String用相同的键在中间放置一个
Any ideas?
有任何想法吗？
Thanks!
谢谢！
EDIT: some code:
编辑：一些代码：
//onCreate()
sp = getPreferences(MODE_PRIVATE);
// other method
boolean showIntro = sp.getBoolean(IntroActivity.SHOW_INTRO, true); // Exception is here
showIntroCheckBox.setChecked(showIntro);
If it matters, the code which throws the exception is inside a button's onClick
如果重要的话，抛出异常的代码在按钮的内部 onClick
回答by Geobits
If there's ever been a string with that key, even if by accident, it will stay there until you clear the app's data or uninstall. Try uninstalling it to see if it still occurs.
如果曾经有一个带有该键的字符串，即使是偶然的，它也会保留在那里，直到您清除应用程序的数据或卸载。尝试卸载它，看看它是否仍然存在。
回答by Sam
The exception occurs in this Android method:
这个Android方法发生了异常：
public boolean getBoolean(String key, boolean defValue) {
synchronized (this) {
awaitLoadedLocked();
Boolean v = (Boolean)mMap.get(key); // On this line
return v != null ? v : defValue;
}
}
The only sense I can make of this error is that your are reusing the key IntroActivity.SHOW_INTROfor a String somewhere else in your code.
我对这个错误的唯一理解是你IntroActivity.SHOW_INTRO在代码中的其他地方重用了 String的键。
回答by Nishant
Use the below code to set the boolean value in SharedPreference:
使用以下代码在 中设置布尔值SharedPreference：
SharedPreferences appSharedPrefs = PreferenceManager
.getDefaultSharedPreferences(this.getApplicationContext());
Editor prefsEditor = appSharedPrefs.edit();
prefsEditor.putBoolean(IntroActivity.SHOW_INTRO, true);
prefsEditor.commit();
And to retrieve the boolean value from SharedPreferenceuse this code:
并SharedPreference使用以下代码检索布尔值：
SharedPreferences appSharedPrefs = PreferenceManager
.getDefaultSharedPreferences(this.getApplicationContext());
boolean showIntro = appSharedPrefs.getBoolean(IntroActivity.SHOW_INTRO, true);
回答by BBdev
I am assuming that
我假设
sp.getBoolean(IntroActivity.SHOW_INTRO, true)// this line returns a String value.
so you can do like this
所以你可以这样做
boolean showIntro = Boolean.parseBoolean(sp.getBoolean(IntroActivity.SHOW_INTRO, true));
回答by Anil Jadhav
The line sp.getBoolean(IntroActivity.SHOW_INTRO, true)// this line returns a String value.
sp.getBoolean(IntroActivity.SHOW_INTRO, true)// 这一行返回一个字符串值。
so you have to do as given below,
所以你必须按照下面给出的做，
String flag=sp.getBoolean(IntroActivity.SHOW_INTRO, true);
if(flag.equalsIgnoreCase("true")){
boolean showIntro = true;
}else{
boolean showIntro = false;
}
Try this it will definitely works.
试试这个它肯定会起作用。
回答by Abhilash
This is the common mistake which everyone will make with the key , I guess IntroActivity.SHOW_INTRO="xyz_key" if , You use the same "xyz_key" for another Constant this error will occur so the value of key should be unique.. Happy coding :)
这是每个人都会在使用 key 时犯的常见错误，我猜 IntroActivity.SHOW_INTRO="xyz_key" 如果，你对另一个常量使用相同的“xyz_key”会发生这个错误，所以 key 的值应该是唯一的..快乐编码:)
回答by hzitoun
Got this exception when, by mistake, I've given to two preferences the samekeyin the XML file android:key="your_key"!
当我错误地在 XML 文件中为两个首选项提供了相同的键时，出现了这个异常android:key="your_key"！
So double checking your settings.xml may help.
因此，仔细检查您的 settings.xml 可能会有所帮助。
