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
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,它工作正常.我不知道发生了什么以及如何解决这个问题.我将不胜感激任何帮助.
在这里添加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>
为了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.它未能说明以下内容
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
得到它了.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.
解决方法
得到它了.由于某种原因,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>
