Android 安卓网络视图问题

我正在尝试为Android制作一个webview应用程序。我为IOS做了一个，效果很好，但我在安卓系统上遇到了严重的问题。我已经在模拟器的屏幕上看到了图标，但当它运行时，它会说“不幸的是…已经停止”，然后我会出现多个错误。我不太确定该怎么办，因为我对安卓这个东西非常熟悉。我将非常感激能得到的一切帮助

谢谢

04-29 21:55:37.628    1113-1113/myname.appname.appname E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: myname.appname.appname, PID: 1113
    java.lang.RuntimeException: Unable to start activity ComponentInfo{myname.appname.appname/myname.appname.appname.MainActivity}: java.lang.NullPointerException

            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)

            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)

            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:5017)

            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:779)

            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)

            at dalvik.system.NativeStart.main(Native Method)

     Caused by: java.lang.NullPointerException

            at myname.appname.appname.MainActivity.onCreate(MainActivity.java:21)

            at android.app.Activity.performCreate(Activity.java:5231)

            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)

            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)

            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)

            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:5017)

            at java.lang.reflect.Method.invokeNative(Native Method)

            at java.lang.reflect.Method.invoke(Method.java:515)

我的MainActivity.java是

package byname.appname.appname;

import android.annotation.SuppressLint;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.webkit.WebSettings;
import android.webkit.WebView;

@SuppressLint("SetJavaScriptEnabled")
public class MainActivity extends ActionBarActivity {

    private WebView mWebView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // Enable Javascript
        WebSettings webSettings = mWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
        mWebView.loadUrl("http://beta.html5test.com/");

        mWebView = (WebView) findViewById(R.id.activity_main_webview);


    }

}

我的AndroidManifest.xml是

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="byname.appname.appname" >

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="myname.appname.appname.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

    <uses-permission android:name="android.permission.INTERNET" />

</manifest>

我的activity_main.xml是

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">


    <WebView
        android:id="@+id/activity_main_webview"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</FrameLayout>

---

请帮帮我

在此行中，mWebView为空：

WebSettings webSettings = mWebView.getSettings();

将此行放在

setContentView

之后的第一位，而不是最后一位。以获取对Web视图的引用

mWebView = (WebView) findViewById(R.id.activity_main_webview);

所以它应该是这样的：

mWebView = (WebView) findViewById(R.id.activity_main_webview);
WebSettings webSettings = mWebView.getSettings();
webSettings.setJavaScriptEnabled(true);
mWebView.loadUrl("http://beta.html5test.com/");