Question

当我从Eclipse安装我的应用程序到模拟器时，我有时在日志“线程退出未捕获的异常”中收到错误。其他SO帖子指的是这个，但“原因”通常是由开发者构建的活动。我的原因似乎是一些Android类。我已经尝试了Project＆gt; Clean，但这并没有改变任何东西。此外，即使出现此错误，该应用程序运行正常。它的外观似乎没有任何押韵或理由。想法？

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04-09 21:22:49.487: W/dalvikvm(1462): threadid=1: thread exiting with uncaught exception (group=0x40a13300)
04-09 21:22:49.497: E/AndroidRuntime(1462): FATAL EXCEPTION: main
04-09 21:22:49.497: E/AndroidRuntime(1462): java.lang.RuntimeException: Unable to instantiate application com.example.blobtag2.GlobalAppContext: java.lang.NullPointerException
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.app.LoadedApk.makeApplication(LoadedApk.java:501)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4124)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.app.ActivityThread.access$1300(ActivityThread.java:130)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1255)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.os.Looper.loop(Looper.java:137)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.app.ActivityThread.main(ActivityThread.java:4745)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at java.lang.reflect.Method.invokeNative(Native Method)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at java.lang.reflect.Method.invoke(Method.java:511)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at dalvik.system.NativeStart.main(Native Method)
04-09 21:22:49.497: E/AndroidRuntime(1462): Caused by: java.lang.NullPointerException
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.app.LoadedApk.initializeJavaContextClassLoader(LoadedApk.java:377)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.app.LoadedApk.getClassLoader(LoadedApk.java:320)
04-09 21:22:49.497: E/AndroidRuntime(1462):     at android.app.LoadedApk.makeApplication(LoadedApk.java:493)
04-09 21:22:49.497: E/AndroidRuntime(1462):     ... 11 more

编辑 - 清单：

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.blobtag2"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="8"
    android:targetSdkVersion="15" />

<uses-permission android:name="android.permission.INTERNET" />

<application
    android:name=".GlobalAppContext"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <service android:name=".service.RESTService" />

    <activity
        android:name=".MainActivity"
        android:label="@string/title_activity_main" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".ResultsActivity"
        android:label="@string/title_activity_results_activity" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.example.blobtag2.MainActivity" />
    </activity>
    <activity
        android:name=".PlaceActivity"
        android:label="@string/title_activity_place_activity" >
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.example.blobtag2.ResultsActivity" />
    </activity>
</application>

</manifest>

globalappcontext代码：

public class GlobalAppContext extends Application {
private static VenueList venueList;

@Override
public void onCreate() {
    venueList = new VenueList();
}

public static VenueList getVenueList() {
    return venueList;
}

/*do I still need this, since I have it in the venueList class?
public static void setPlaceName(String s) {
    venueList = s;
}
**/
}

Answer 1

将GlobalAppContext.java更改为：

public class GlobalAppContext {

    private static VenueList mVenueList = null;

    //----------------------------
    // Uses the Singleton method of Bill Pugh.
    // https://en.wikipedia.org/wiki/Singleton_pattern
    //----------------------------

    // --- Singleton code
    private GlobalAppContext() { }

    private static class GlobalAppContextHolder {
        public static final GlobalAppContext INSTANCE = new GlobalAppContext();
    }

    public static GlobalAppContext getInstance() {
        if (mVenueList == null) {
            mVenueList = new VenueList();
        }
        return GlobalAppContext.INSTANCE;
    }
    // --- End Singleton code

    public static VenueList getVenueList() {
        return mVenueList;
    }
}

并使用以下内容调用此全局类：

... snip ....
private static GlobalAppContext mGlobal = null;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    if (mGlobal == null) {
        mGlobal = GlobalAppContext.getInstance();
    }

    setContentView(R.layout.your_layout);
}

现在您可以像这样访问“VenueList”：

VenueList venueList = mGlobal.getVenueList();

线程退出与未捕获的异常 - 但应用程序仍按设计运行

1 个答案: