我是android新手…尝试从动态壁纸打开URL时遇到麻烦.

打开URL的代码：

            Intent intent = new Intent(Intent.ACTION_VIEW);
            intent.setData(Uri.parse(url));

            Activity activity = new Activity();
            activity.startActivity(intent);

但是我只是得到一个NullpointerException：

 java.lang.NullPointerException
     at android.app.Activity.startActivityForResult(Activity.java:2749)
     at android.app.Activity.startActivity(Activity.java:2855)
     at org.amble.graphics.HToolbar$URLEntry.run(HToolbar.java:81)
     at org.amble.graphics.HToolbar.doTouch(HToolbar.java:188)
     at com.mobstar.undeadpirate.autopaper.PiratePaperPainter.doTouchEvent(PiratePaperPainter.java:245)
     at com.mobstar.undeadpirate.autopaper.LiveWallpaperService$WallpaperEngine.onTouchEvent(LiveWallpaperService.java:117)
     at android.service.wallpaper.WallpaperService$IWallpaperEngineWrapper.executeMessage(WallpaperService.java:832)
     at com.android.internal.os.HandlerCaller$MyHandler.handleMessage(HandlerCaller.java:45)
     at android.os.Handler.dispatchMessage(Handler.java:99)
     at android.os.Looper.loop(Looper.java:123)
     at android.app.ActivityThread.main(ActivityThread.java:4363)
     at java.lang.reflect.Method.invokeNative(Native Method)
     at java.lang.reflect.Method.invoke(Method.java:521)
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
     at dalvik.system.NativeStart.main(Native Method)

我的清单看起来像这样

<?xml version="1.0" encoding="utf-8"?>
<manifest 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:versionCode="1"
    android:versionName="1.0" package="com.nubjub.wallpapertest">
    <application 
        android:label="@string/app_name" android:debuggable="true" android:icon="@drawable/icon">
        <service 
            android:name="WallpaperTest"
            android:enabled="true"
            android:icon="@drawable/icon"
            android:label="@string/app_name"
            android:permission="android.permission.BIND_WALLPAPER">
            <intent-filter android:priority="1" >
                <action android:name="android.service.wallpaper.WallpaperService" />
            </intent-filter>
            <meta-data 
                android:name="android.service.wallpaper" 
                android:resource="@xml/wallpaper" />
        </service>
    </application>
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-sdk android:minSdkVersion="7" />
</manifest> 

解决方法:

当然,您可以从动态壁纸打开浏览器！所需的代码是：

Intent myIntent = new Intent(Intent.ACTION_VIEW,
                             Uri.parse("http://www.example.com"));
myIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(myIntent);

您唯一需要设置的是动态壁纸应该能够启动一个新任务,这是我们通过Intent.setFlags(int flag)行执行的.

您无需实例化新活动,建议您阅读android活动生命周期以及意图的确切含义！