在 shouldOverrideUrlLoading() 方法中膨胀自定义 toast 消息时出现 NullPointerException

Question

我有一个显示 webView 的应用程序，每次在 webView 中加载 url 时，我都会尝试显示一条自定义 toast 消息，上面写着 "Please wait".. 所以我夸大了这个自定义 toast 消息在 shouldOverrideUrlLoading(WebView view, String url) 方法中。如果我启动应用程序并等待 url 加载，应用程序工作正常。加载 [=31 时也会出现消息=]..

当我启动应用程序然后突然退出时出现问题。没有等待 url 加载。应用程序崩溃，在 --

处出现空指针异常

LayoutInflater iflater = (LayoutInflater)getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

我无法找到防止此异常和应用程序崩溃的方法-

这是我的代码-

public boolean shouldOverrideUrlLoading(WebView view, String url) {
        Log.i(TAG, "About to load:" + url);
        view.loadUrl(url);

        LayoutInflater nflater = (LayoutInflater)getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);

        View layout = nflater.inflate(R.layout.toast2,
                (ViewGroup) getActivity().findViewById(R.id.tl1));
         TextView textv = (TextView) layout.findViewById(R.id.text);
         textv.setText(R.string.loading);
         final Toast ltoast = new Toast(getActivity());
         ltoast.setView(layout);
         ltoast.show();

         new CountDownTimer(9000, 1000)
         {

             public void onTick(long millisUntilFinished) {ltoast.show();}
             public void onFinish() {ltoast.show();}

         }.start();


        return true;
    }

这是我的 Logcat-

中的错误

07-30 15:26:25.429: E/AndroidRuntime(8701): FATAL EXCEPTION: main
07-30 15:26:25.429: E/AndroidRuntime(8701): java.lang.NullPointerException
07-30 15:26:25.429: E/AndroidRuntime(8701):     at        com.example.itslive.web1Activity$HelloWebViewClient.shouldOverrideUrlLoading(web1Activity.java:673)
 07-30 15:26:25.429: E/AndroidRuntime(8701):    at android.webkit.CallbackProxy.handleMessage(CallbackProxy.java:384)
07-30 15:26:25.429: E/AndroidRuntime(8701):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-30 15:26:25.429: E/AndroidRuntime(8701):     at android.os.Looper.loop(Looper.java:137)
07-30 15:26:25.429: E/AndroidRuntime(8701):     at android.app.ActivityThread.main(ActivityThread.java:4921)
07-30 15:26:25.429: E/AndroidRuntime(8701):     at java.lang.reflect.Method.invokeNative(Native Method)
07-30 15:26:25.429: E/AndroidRuntime(8701):     at java.lang.reflect.Method.invoke(Method.java:511)
07-30 15:26:25.429: E/AndroidRuntime(8701):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
07-30 15:26:25.429: E/AndroidRuntime(8701):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
07-30 15:26:25.429: E/AndroidRuntime(8701):     at dalvik.system.NativeStart.main(Native Method)

这是我的 toast2.xml 文件...

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:id="@+id/tl1"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:orientation="vertical" >

  <TextView android:id="@+id/text"
          android:layout_width="match_parent"
          android:layout_height="wrap_content"
          android:textColor="@color/blue"
          android:paddingLeft="30dp"
          android:paddingRight="30dp"
          />
  </LinearLayout>

Answer 1

试试这样吐司看看

public void showCustomAlert()
{

    Context context = getActivity();
    // Create layout inflator object to inflate toast.xml file
    LayoutInflater inflater = getActivity().getLayoutInflater();

    // Call toast.xml file for toast layout
    View toastRoot = inflater.inflate(R.layout.list_adapter, null);

    Toast toast = new Toast(context);

    // Set layout to toast
    toast.setView(toastRoot);
    toast.setGravity(Gravity.CENTER_HORIZONTAL | Gravity.CENTER_VERTICAL,
            0, 0);
    toast.setDuration(Toast.LENGTH_LONG);
    toast.show();

}

然后你必须做一件事。将 FragmentActivity 的对象创建为 onCreateView FragmentActivity fragActivity=getActivity();那么你必须调用 LayoutInflater inflater = fragActivity.getLayoutInflater();在你的 shouldOverrideUrlLoading 方法中

在 shouldOverrideUrlLoading() 方法中膨胀自定义 toast 消息时出现 NullPointerException

NullPointerException while inflating custom toast message in shouldOverrideUrlLoading() method

android

nullpointerexception

webview

layout-inflater

android-toast