Question

这是我的strings.xml

 <resources>
 <string name="alert_internet">out</string>
 </resources>

我试图在我的主要活动中调用此字符串，如下所示：

 final String net = getString(R.string.alert_internet);

我也检查了我的R.java文件，＆＃39; alert_internet＆＃39;存在。但出于某种原因，每当我启动应用程序时，它都会崩溃到地面。试图获得一个简单的字符串，我做错了什么？

这是我的log.cat

   09-23 13:17:33.092: E/AndroidRuntime(21302): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1573)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1667)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.app.ActivityThread.access$1500(ActivityThread.java:117)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:935)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.os.Handler.dispatchMessage(Handler.java:99)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.os.Looper.loop(Looper.java:130)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.app.ActivityThread.main(ActivityThread.java:3693)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at java.lang.reflect.Method.invokeNative(Native Method)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at java.lang.reflect.Method.invoke(Method.java:507)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:665)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at dalvik.system.NativeStart.main(Native Method)
   09-23 13:17:33.092: E/AndroidRuntime(21302): Caused by: java.lang.NullPointerException
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.content.ContextWrapper.getResources(ContextWrapper.java:80)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.content.Context.getString(Context.java:183)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at com.akilli.ticaret.Main.<init>(Main.java:25)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at java.lang.Class.newInstanceImpl(Native Method)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at java.lang.Class.newInstance(Class.java:1409)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at  android.app.Instrumentation.newActivity(Instrumentation.java:1021)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1565)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     ... 11 more
   09-23 13:17:33.102: E/(179): Dumpstate > /data/log/dumpstate_app_error

Answer 1

Caused by: java.lang.NullPointerException
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.content.ContextWrapper.getResources(ContextWrapper.java:80)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at android.content.Context.getString(Context.java:183)
   09-23 13:17:33.092: E/AndroidRuntime(21302):     at com.akilli.ticaret.Main.<init>(Main.java:25)

在Context之前，您无法将活动用作onCreate()。从类初始化中删除getString()调用（如<init>所暗示的那样）并将其移至onCreate()。

Answer 2

你应该这样称呼它：

getResources().getString(R.string.alert_internet);

在Context上（例如在Activity中）。

此处有更多信息：http://developer.android.com/reference/android/content/Context.html#getResources()

Answer 3

尝试在您的活动的 onCreate() 函数中初始化您的变量。所以：

弦网；

然后在你的 onCreate() net = getString(R.string.alert_internet);

尽管我意识到那时您将无法使用 final 变量。

android应用程序在getString（）行崩溃

3 个答案: