5

我正在使用 resolveActivityInfo 来确定我的应用是否设置为主页启动器：

    PackageManager pm = getPackageManager();

    Intent intent = new Intent(Intent.ACTION_MAIN, null);
    intent.addCategory(Intent.CATEGORY_HOME);   

    userHomePackage = intent.resolveActivityInfo(pm, 0).packageName;
    userHomeActivityClass = intent.resolveActivityInfo(pm, 0).name;     
currentHomeLauncherName = intent.resolveActivityInfo(pm, 0).loadLabel(pm).toString();

它在模拟器和我手头的三个 android 设备上运行良好。

最近我开始收到用户的错误报告，错误日志显示 resolveActivityInfo 失败。如我所见，这只发生在少数运行 android 2.1 update 1 的手机上。由于这个问题，我已经收到了很多关于我的应用程序的正面评论和一些负面评论。

有什么建议可能是错的吗？

java.lang.NullPointerException
    at android.os.Parcel.readException(Parcel.java:1224)
    at android.os.Parcel.readException(Parcel.java:1206)
    at android.content.pm.IPackageManager$Stub$Proxy.resolveIntent(IPackageManager.java:1418)
    at android.app.ApplicationContext$ApplicationPackageManager.resolveActivity(ApplicationContext.java:2046)
    at android.content.Intent.resolveActivityInfo(Intent.java:3790)
    at com.myapp.myappname.Launcher.setAsHomeApplicationBeforeFroyo(Launcher.java:336)

或者

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.myapp.myappname/com.myapp.myappname.Launcher}: java.lang.NullPointerException
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2497)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2513)
    at android.app.ActivityThread.access$2200(ActivityThread.java:119)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1864)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:123)
    at android.app.ActivityThread.main(ActivityThread.java:4370)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:521)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:862)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:620)
    at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
    at android.os.Parcel.readException(Parcel.java:1224)
    at android.os.Parcel.readException(Parcel.java:1206)
    at android.content.pm.IPackageManager$Stub$Proxy.resolveIntent(IPackageManager.java:1418)
    at android.app.ApplicationContext$ApplicationPackageManager.resolveActivity(ApplicationContext.java:2046)
    at android.content.Intent.resolveActivityInfo(Intent.java:3790)
    at com.myapp.myappname.Launcher.showHomeChooserDialog(Launcher.java:141)
    at com.myapp.myappname.Launcher.showNextActivity(Launcher.java:122)
    at com.myapp.myappname.Launcher.onCreate(Launcher.java:59)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2460)
    ... 11 more
java.lang.NullPointerException
    at android.os.Parcel.readException(Parcel.java:1224)
    at android.os.Parcel.readException(Parcel.java:1206)
    at android.content.pm.IPackageManager$Stub$Proxy.resolveIntent(IPackageManager.java:1418)
    at android.app.ApplicationContext$ApplicationPackageManager.resolveActivity(ApplicationContext.java:2046)
    at android.content.Intent.resolveActivityInfo(Intent.java:3790)
    at com.myapp.myappname.Launcher.showHomeChooserDialog(Launcher.java:141)
4

2 回答 2

4

来自 TeslaCoil Software 的 Kevin 在这里。很抱歉延迟回复您。这就是我用来在我的应用程序中获取 Home 组件的方法：

public static ComponentName getHomeComponent(PackageManager PM) {
    Intent home_intent = new Intent("android.intent.action.MAIN");
    home_intent.addCategory("android.intent.category.HOME");
    home_intent.addCategory("android.intent.category.DEFAULT");

    ComponentName cn = home_intent.resolveActivity(PM);
    if (cn == null)
        Log.v(TAG, "[Default] package:null");
    else
        Log.v(TAG, "[Default] package:" + cn.getPackageName() + " class:" + cn.getClassName());

    return cn;
}

resolveActivity 通常不会返回 null，因为如果没有默认设置，它似乎会返回解析器活动。但在某些手机或其他东西上，它可能会返回 null 只是为了让事情变得有趣。也许resolveActivityInfo 调用resolveActivity 但没有正确处理null 情况。

于 2011-02-19T04:16:54.640 回答
1

对android源做了一些研究，我现在倾向于同意Commonsware我的代码是正确的。我实际上在 3 周前重新设计了它以使用 packagemanager.resolveActivity 而不是 intent.resolveactivity：

this.pm = context.getPackageManager();

    try {
        Intent homeintent = new Intent(Intent.ACTION_MAIN);
        homeintent.addCategory(Intent.CATEGORY_HOME);
        homeintent.addCategory(Intent.CATEGORY_DEFAULT);// seems not needed here since This is a synonym for
                                // including
        // the CATEGORY_DEFAULT in your supplied Intent per doc

        this.resolveInfo = pm.resolveActivity(homeintent, PackageManager.MATCH_DEFAULT_ONLY);

        ActivityInfo activityInfo = resolveInfo.activityInfo;

        userHomeLauncherPackage = activityInfo.packageName;
        userHomeLauncherClass = activityInfo.name;

        userHomeLauncherName = activityInfo.loadLabel(pm).toString();

        if (userHomeLauncherClass.contains("ResolverActivity"))
        userHomeLauncherName = "";

    } catch (Exception e) {
        throw new Exception(e);
    }

它没有帮助，所以偶尔仍然会出现这些错误......

基于源代码，

ComponentName Intent.resolveActivity (PackageManager pm)

或者

ActivityInfo Intent.resolveActivityInfo (PackageManager pm, int flags)

调用 android.app.ContextImpl 类中定义的相同方法：

ResolveInfo info = pm.resolveActivity(this, PackageManager.MATCH_DEFAULT_ONLY)

它的定义如下：

        @Override
    public ResolveInfo resolveActivity(Intent intent, int flags) {
        try {
            return mPM.resolveIntent(
                intent,
                intent.resolveTypeIfNeeded(mContext.getContentResolver()),
                flags);
        } catch (RemoteException e) {
            throw new RuntimeException("Package manager has died", e);
        }
    }

所以在这一点上我得出的结论是我对此无能为力:(

于 2011-02-20T18:32:07.867 回答