安卓：content.res.Resources$NotFoundException

如何解决安卓：content.res.Resources$NotFoundException

每当我尝试从 strings.xml 访问字符串时，我都会收到 android.content.res.Resources$NotFoundException 的错误，当我通过对字符串值进行硬编码来执行相同操作时，我不会遇到任何问题. 谁能帮我理解这里的问题？

我在下面的 UnitUtils.java 文件中遇到了这个问题，我在下面评论的行中遇到了错误

UnitUtils.java

public class UnitUtils {

    public static String getToken(String name) {
        return unitNametoToken.get(name);
    }

    private static Map<String,String> unitNametoToken = new HashMap<String,String>();
    static {

        //unitNametoToken.put(Resources.getSystem().getString(R.string.tempkelvin),"K"); dosent works
        //unitNametoToken.put("Celsius","C"); works
        unitNametoToken.put("Fahrenheit","F");
        unitNametoToken.put("Celsius","°C");
        unitNametoToken.put("millimeter","mm");
        unitNametoToken.put("centimeter","cm");
        unitNametoToken.put("meter","m");
        unitNametoToken.put("kilometer","km");
        unitNametoToken.put("inch","in");
        unitNametoToken.put("foot/feet","ft");
        unitNametoToken.put("yard","yd");
        unitNametoToken.put("mile","mi");
        unitNametoToken.put("nautical mile","nmi");

    }

    public static Map<String,String> getUnitNametoToken() {
        return unitNametoToken;
    }
}

调用 unitutils 的代码片段（检查注释行） 主Activity.java

unitFrom = mFromSpinner.getItemAtPosition(0).toString();
//fromInput.setHint(UnitUtils.getToken(unitFrom));
unitTo = mToSpinner.getItemAtPosition(0).toString();
toInput.setHint(UnitUtils.getToken(unitTo));

if(view.getParent() == mFromSpinner) {
     unitFrom = mFromSpinner.getItemAtPosition(position).toString()
}

strings.xml

<!--    temperature strings-->
    <string name="tempcelcius">Celsius</string>
    <string name="tempkelvin">Kelvin</string>
    <string name="tempfaren">Fahrenheit</string>

LogCat

E/.rex.calculato: No package ID 7f found for ID 0x7f0f0082.
D/AndroidRuntime: Shutting down VM
E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.rex.calculator,PID: 7531
    java.lang.ExceptionInInitializerError
        at com.rex.unitconverter.UnitUtils.getToken(UnitUtils.java:13)
        at com.rex.unitconverter.UnitConverteractivity.onItemSelected(UnitConverteractivity.java:94)
        at android.widget.AdapterView.fireOnSelected(AdapterView.java:957)
        at android.widget.AdapterView.dispatchOnItemSelected(AdapterView.java:946)
        at android.widget.AdapterView.access$300(AdapterView.java:55)
        at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:910)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7698)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:952)
     Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x7f0f0082
        at android.content.res.Resources.getText(Resources.java:444)
        at android.content.res.Resources.getString(Resources.java:537)
        at com.rex.unitconverter.UnitUtils.<clinit>(UnitUtils.java:18)
        at com.rex.unitconverter.UnitUtils.getToken(UnitUtils.java:13) 
        at com.rex.unitconverter.UnitConverteractivity.onItemSelected(UnitConverteractivity.java:94) 
        at android.widget.AdapterView.fireOnSelected(AdapterView.java:957) 
        at android.widget.AdapterView.dispatchOnItemSelected(AdapterView.java:946) 
        at android.widget.AdapterView.access$300(AdapterView.java:55) 
        at android.widget.AdapterView$SelectionNotifier.run(AdapterView.java:910) 
        at android.os.Handler.handleCallback(Handler.java:938) 
        at android.os.Handler.dispatchMessage(Handler.java:99) 
        at android.os.Looper.loop(Looper.java:223) 
        at android.app.ActivityThread.main(ActivityThread.java:7698) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:952) 
I/Process: Sending signal. PID: 7531 SIG: 9