Java NullPointerException从Android Studio中的资产加载htm文件

我想检索一个htm文件并在Android应用程序内的webview中显示它。这是我的代码：

private void ShowPage()
{
        location = "file:///android_asset/general.htm";
        webview = (WebView) findViewById(R.id.webview);
        webview.loadUrl(location);
        WebSettings webSettings = webview.getSettings();
        webSettings.setBuiltInZoomControls(true);

}

我得到一个NullPointerException？我哪里做错了？这段代码在Eclipse中运行良好

堆栈跟踪：

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.test/com.test.HomeActivity}: java.lang.NullPointerException
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2184)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at com.test.HomeActivity.setWebPage(HomeActivity.java:108)
            at com.test.HomeActivity.onSectionAttached(HomeActivity.java:81)
            at com.test.HomeActivity$PlaceholderFragment.onAttach(HomeActivity.java:186)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:903)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
            at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
            at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
            at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:548)
            at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1171)
            at android.app.Activity.performStart(Activity.java:5285)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2157)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2233)
            at android.app.ActivityThread.access$800(ActivityThread.java:135)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5001)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
            at dalvik.system.NativeStart.main(Native Method)

和资产文件夹：

---

我已经确定了问题所在-我使用了导航抽屉片段并错误地引用了webview。我不知道为什么应用程序在尝试加载url时崩溃。谢谢大家的帮助

你从哪里得到NullPointerException？检查R.id.webview是否存在。请发布堆栈跟踪。我在webview.loadUrllocation获得错误；这意味着你的位置错误，或者该位置上不存在元素。我在Android Studio中添加了资产文件夹的屏幕截图，我缺少什么？