我试图从URL调用web并在webview中显示它。但是我得到了一个错误。
我已经看到了日志,但是我仍然不明白我的代码出了什么问题。
这是我的XMl代码
<WebView
android:id="@+id/adBanner1"
android:layout_width="fill_parent"
android:layout_height="0dip"
android:layout_weight="1" />
这是我的java代码。
private WebView adsbanner;
adsbanner = (WebView) findViewById(R.id.adBanner1);
startWebView("http://www.androidexample.com/media/webview/login.html");
private void startWebView(String url) {
adsbanner.setWebViewClient(new WebViewClient() {
//If you will not use this method url links are opeen in new brower not in webview
public boolean shouldOverrideUrlLoading(WebView view, String url) {
view.loadUrl(url);
return true;
}
});
adsbanner.getSettings().setJavaScriptEnabled(true);
adsbanner.loadUrl(url);
}
这是我的logcat
06-25 20:47:04.162: E/AndroidRuntime(2461): FATAL EXCEPTION: main
06-25 20:47:04.162: E/AndroidRuntime(2461): Process: com.indomultimedia.hellobali, PID: 2461
06-25 20:47:04.162: E/AndroidRuntime(2461): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.indomultimedia.hellobali/com.indomultimedia.hellobali.MainHelloballi}: java.lang.NullPointerException
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2282)
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2340)
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.app.ActivityThread.access$800(ActivityThread.java:157)
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1247)
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.os.Handler.dispatchMessage(Handler.java:102)
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.os.Looper.loop(Looper.java:157)
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.app.ActivityThread.main(ActivityThread.java:5293)
06-25 20:47:04.162: E/AndroidRuntime(2461): at java.lang.reflect.Method.invokeNative(Native Method)
06-25 20:47:04.162: E/AndroidRuntime(2461): at java.lang.reflect.Method.invoke(Method.java:515)
06-25 20:47:04.162: E/AndroidRuntime(2461): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1265)
06-25 20:47:04.162: E/AndroidRuntime(2461): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1081)
06-25 20:47:04.162: E/AndroidRuntime(2461): at dalvik.system.NativeStart.main(Native Method)
06-25 20:47:04.162: E/AndroidRuntime(2461): Caused by: java.lang.NullPointerException
06-25 20:47:04.162: E/AndroidRuntime(2461): at com.indomultimedia.hellobali.MainHelloballi.onCreate(MainHelloballi.java:60)
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.app.Activity.performCreate(Activity.java:5389)
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
06-25 20:47:04.162: E/AndroidRuntime(2461): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2246)
06-25 20:47:04.162: E/AndroidRuntime(2461): ... 11 more
D
要使用webview,我们需要在manifest文件中添加权限。在Androidmanifest.xml文件
下添加以下代码<manifest xlmns:android...>
...
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
</manifest>
试试这些:
public class WebPageLoader extends Activity
{
final Activity activity = this;
private String html;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
setContentView(R.layout.activity_main);
WebView webView = (WebView) findViewById(R.id.webview);
webView.getSettings().setJavaScriptEnabled(true);
webview.loadUrl("http://www.androidexample.com/media/webview/login.html");
webView.setWebChromeClient(new WebChromeClient() {
public void onProgressChanged(WebView view, int progress)
{
activity.setTitle("Loading...");
activity.setProgress(progress * 100);
if(progress == 100)
activity.setTitle(R.string.app_name);
}
});
webView.setWebViewClient(new WebViewClient() {
@Override
public void onReceivedError(WebView view, int errorCode, String description, String failingUrl)
{
}
@Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
view.loadUrl(url);
return true;
}
});
}
}