无法在Android中使用WebView加载网页

时间：2011-05-09 23:25:19

标签： android webview android-webview

我最近接受了Android开发，我正在寻找使用WebView显示网页。我从Google网站上提供的示例中选择了，并且由于某种原因，模拟器一直说页面不可用。我在StackOverflow中搜索并找到了与WebViewClient相关的链接。我也尝试了但是没有运气，我已经多次检查过互联网许可的清单条目及其存在。作为测试，我运行了模拟器中可用的浏览器，确定我的防火墙突然出现了是否允许其访问的问题。当我从程序运行它时，弹出窗口从未找到我。我拥有的代码就是Google页面的内容

    mWebView = (WebView) findViewById(R.id.webview);
    mWebView.getSettings().setJavaScriptEnabled(true);
    mWebView.loadUrl("http://www.google.com");  
    mWebView.setWebViewClient(new HelloWebViewClient());

    private class HelloWebViewClient extends WebViewClient {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
        view.loadUrl(url);
        return true;
    }

我尝试使用loadData直接加载简单的html，它运行正常。我不知道发生了什么以及如何解决这个问题。我很感激任何帮助。

在此处添加Android Manifest 

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.example.hellowebview"
  android:versionCode="1"
  android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />

<application android:icon="@drawable/icon" android:label="@string/app_name">
    <activity android:name=".HelloWebView"
              android:label="@string/app_name"
              android:theme="@android:style/Theme.NoTitleBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>     
 <uses-permission android:name="android.permission.INTERNET" />
</application>
</manifest>

要检查它是否只是一个WebView，我尝试使用httpGet和httpResonse类访问互联网并遇到同样的问题，代码无法连接到给定的站点。它未能说明以下

  

05-10 00:37:53.191: WARN/System.err(294): java.net.UnknownHostException: feeds.feedburner.com
05-10 00:37:53.230: WARN/System.err(294):     at java.net.InetAddress.lookupHostByName(InetAddress.java:513)
05-10 00:37:53.230: WARN/System.err(294):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:278)
05-10 00:37:53.230: WARN/System.err(294):     at java.net.InetAddress.getAllByName(InetAddress.java:242)
05-10 00:37:53.250: WARN/System.err(294):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:136)
05-10 00:37:53.250: WARN/System.err(294):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
05-10 00:37:53.250: WARN/System.err(294):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
05-10 00:37:53.271: WARN/System.err(294):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:348)
05-10 00:37:53.271: WARN/System.err(294):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
05-10 00:37:53.280: WARN/System.err(294):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
05-10 00:37:53.291: WARN/System.err(294):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
05-10 00:37:53.301: WARN/System.err(294):     at com.example.hellowebview.HelloWebView.onCreate(HelloWebView.java:43)
05-10 00:37:53.301: WARN/System.err(294):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-10 00:37:53.309: WARN/System.err(294):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
05-10 00:37:53.322: WARN/System.err(294):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-10 00:37:53.330: WARN/System.err(294):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-10 00:37:53.340: WARN/System.err(294):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-10 00:37:53.350: WARN/System.err(294):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-10 00:37:53.350: WARN/System.err(294):     at android.os.Looper.loop(Looper.java:123)
05-10 00:37:53.361: WARN/System.err(294):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-10 00:37:53.361: WARN/System.err(294):     at java.lang.reflect.Method.invokeNative(Native Method)
05-10 00:37:53.372: WARN/System.err(294):     at java.lang.reflect.Method.invoke(Method.java:521)
05-10 00:37:53.380: WARN/System.err(294):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-10 00:37:53.380: WARN/System.err(294):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-10 00:37:53.401: WARN/System.err(294):     at dalvik.system.NativeStart.main(Native Method)
05-10 00:37:56.773: WARN/ActivityManager(58): Launch timeout has expired, giving up wake lock!
05-10 00:37:58.083: WARN/ActivityManager(58): Activity idle timeout for HistoryRecord{44fc9108 com.example.hellowebview/.HelloWebView}
05-10 00:38:06.300: DEBUG/KeyguardViewMediator(58): pokeWakelock(5000)
05-10 00:38:06.651: INFO/ARMAssembler(58): generated scanline__00000077:03545404_00000004_00000000 [ 47 ipp] (67 ins) at [0x3724c8:0x3725d4] in 7266287 ns
05-10 00:38:06.720: INFO/ARMAssembler(58): generated scanline__00000177:03515104_00001001_00000000 [ 91 ipp] (114 ins) at [0x371380:0x371548] in 1486222 ns
05-10 00:38:30.430: DEBUG/AndroidRuntime(294): Shutting down VM
05-10 00:38:30.430: WARN/dalvikvm(294): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
05-10 00:38:30.752: ERROR/AndroidRuntime(294): FATAL EXCEPTION: main
05-10 00:38:30.752: ERROR/AndroidRuntime(294): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.hellowebview/com.example.hellowebview.HelloWebView}: java.lang.NullPointerException
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at android.os.Looper.loop(Looper.java:123)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at java.lang.reflect.Method.invokeNative(Native Method)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at java.lang.reflect.Method.invoke(Method.java:521)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at dalvik.system.NativeStart.main(Native Method)
05-10 00:38:30.752: ERROR/AndroidRuntime(294): Caused by: java.lang.NullPointerException
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at com.example.hellowebview.HelloWebView.onCreate(HelloWebView.java:51)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
05-10 00:38:30.752: ERROR/AndroidRuntime(294):     ... 11 more

知道了。由于某种原因，设置权限的顺序很重要。我在清单文件中更改了我的权限设置的顺序，并且它有效。这是修改后的清单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.hellowebview"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
<uses-permission android:name="android.permission.INTERNET" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".HelloWebView"
          android:label="@string/app_name"
          android:theme="@android:style/Theme.NoTitleBar">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>     
</application>
</manifest>

我不确定这有什么意义，但如果有人能详细说明，我将不胜感激。

3 个答案:

答案 0 :(得分：8)

知道了。由于某种原因，设置权限的顺序很重要。我在清单文件中更改了我的权限设置的顺序，并且它有效。这是修改后的清单

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  package="com.example.hellowebview"
  android:versionCode="1"
  android:versionName="1.0">
<uses-sdk android:minSdkVersion="8" />
 <uses-permission android:name="android.permission.INTERNET" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
    <activity android:name=".HelloWebView"
              android:label="@string/app_name"
              android:theme="@android:style/Theme.NoTitleBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>     
</application>
</manifest>

答案 1 :(得分：5)

        mWebView = (WebView) findViewById(R.id.webview);     
        WebSettings setting =mWebView.getSettings();
        mWebView.setWebViewClient(new WebViewClient() {
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
        return true;
        }
        mWebView.loadUrl("http://www.google.com");

使用此代码.shouldOverrideUrlLoading（）不使用compulsary.use此代码请回复此代码是否工作

答案 2 :(得分：1)

您的代码看起来很好。我会通过浏览Android浏览器上的几个页面来确保互联网在模拟器上正常运行。在仿真器失去网络访问权限之前，我遇到了问题。

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