Android 1.6 SDK WebView问题

Question

I've narrowed down the problem to WebView; my application force closes every time. If I take out the WebView and put in a color change button or something, the case switching works and the application loads. I'm fairly new to the plaform, but I'm (mostly) copying directly from examples here for WebViews.

Application.java

package com.xxxx.xxxxx;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.webkit.WebView;

public class Application extends Activity {

  @Override
  public void onCreate(Bundle icicle) {

    super.onCreate(icicle);
    setContentView(R.layout.main);

  }

  public void myClickHandler(View view) {

   WebView engine = (WebView) findViewById(R.id.webview);
   switch (view.getId()) {

       case R.id.Button1:
        engine.loadUrl("http://digg.com");
        break;

       case R.id.Button2:
        engine.loadUrl("http://reddit.com");
        break;

    }

     }

} 

main.xml

<?xml version="1.0" encoding="utf-8"?>
<ScrollView
    android:id="@+id/ScrollParent"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android"> 

 <LinearLayout android:id="@+id/MainMenuLayout"
  android:layout_width="310px"
   android:layout_height="fill_parent"
   android:orientation="vertical">

   <TextView 
    android:id="@+id/Application"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:text="Application Name..." />

   <Button android:id="@+id/Button1"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:text="Digg"
         android:onClick="myClickHandler"/>

        <Button android:id="@+id/Button2"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:text="Reddit"
         android:onClick="myClickHandler"/>

 </LinearLayout>

 <LinearLayout  
  android:orientation="vertical"  
  android:layout_width="fill_parent"  
  android:layout_height="fill_parent"  >  

     <WebView
      android:id="@+id/webview"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"/>

 </LinearLayout>
</ScrollView>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.qxmd.ecgguide"
      android:versionCode="1"
      android:versionName="1.0">
    <uses-permission android:name="android.permission.INTERNET" />

    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".Application"
                  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>


</manifest> 

Answer 1

Your layout root is a ScrollView with two child nodes. ScrollView only supports one child node. If you look at the ADB Log, the exception thrown when your application crashes tells you this:

Caused by: java.lang.IllegalStateException: ScrollView can host only one direct child

One possible solution would be to create single layout that the ScrollView manages, and have your two existing LinearLayouts be children of the new layout. Here's a direct modification of your original main.xml:

<?xml version="1.0" encoding="utf-8"?>
<ScrollView
    android:id="@+id/ScrollParent"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    xmlns:android="http://schemas.android.com/apk/res/android">

<!-- new container layout for the original two layouts -->
<LinearLayout
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical">

 <!-- original first child layout, now a child of the wrapper -->
 <LinearLayout android:id="@+id/MainMenuLayout"
  android:layout_width="310px"
   android:layout_height="fill_parent"
   android:orientation="vertical">

   <TextView 
    android:id="@+id/Application"
      android:layout_width="fill_parent"
      android:layout_height="wrap_content"
      android:text="Application Name..." />

   <Button android:id="@+id/Button1"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:text="Digg"
         android:onClick="myClickHandler"/>

        <Button android:id="@+id/Button2"
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:text="Reddit"
         android:onClick="myClickHandler"/>

 </LinearLayout>

 <!-- the original second child layout, now also a child of the wrapper -->
 <LinearLayout  
  android:orientation="vertical"  
  android:layout_width="fill_parent"  
  android:layout_height="fill_parent"  >  

     <WebView
      android:id="@+id/webview"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"/>

 </LinearLayout>

</LinearLayout>
</ScrollView>