Question

在这里遇到错误

 try {
           PackageManager pm = MyApplication.getInstance().getPackageManager();
           PackageInfo packageInfo = process.getPackageInfo(MyApplication.getInstance(), 0);
           info.name = packageInfo.applicationInfo.loadLabel(pm).toString();
     } catch (PackageManager.NameNotFoundException e) {
            e.printStackTrace();
            continue;
 }

日志错误为：

  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.PackageManager android.app.Application.getPackageManager()' on a null object reference
    at com.example.bugfreeram.bugfreeanti.external.ProcessScanTask.doInBackground(ProcessScanTask.java:52)
    at com.example.bugfreeram.bugfreeanti.external.ProcessScanTask.doInBackground(ProcessScanTask.java:21)

MyApplcication类是这样的：

public class MyApplication extends Application {

    private static MyApplication sInstance;

    public static Application getInstance() {
       return sInstance;
    }

   @Override
   public void onCreate() {
       super.onCreate();
       sInstance = this;
   }
}

我在StackOverflow上尝试了所有答案，请帮助我。预先谢谢你

Answer 1

使用Context对象获取PackageManager。像这样：

PackageManager manager = context.getPackageManager();

Answer 2

更改您的AndroidManifest.xml并将MyApplication类添加到android:name

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.app.packagename">
.
.

<application
    android:name=".MyApplication"
    .
    .

</application>

我在使用asynctask的getPackageManager方法中遇到错误

2 个答案: