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In application billing (v3) - understanding nullpointer error

I have an application in which I added to application billing (v3). The published application seems to work fine (at least a small number) of the devices I tested. The code was confused by proguard, but I saved the corresponding proguard mapping.txt file.

Several purchases were made successfully, but I also received crash reports. Then I used retrace.bat to translate the accident stack trace and got the following result:

java.lang.NullPointerException

at com.mycompany.mygame.util.IabHelper.void startSetup(com.mycompany.mygame.util.IabHelper$OnIabSetupFinishedListener)(Unknown Source)
                                      void dispose()
                                      void launchPurchaseFlow(android.app.Activity,java.lang.String,int,com.mycompany.mygame.util.IabHelper$OnIabPurchaseFinishedListener,java.lang.String)
                                      boolean handleActivityResult(int,int,android.content.Intent)
                                      com.mycompany.mygame.util.Inventory queryInventory$337baa91(boolean,java.util.List)
                                      void queryInventoryAsync$69bb631c(java.util.List,com.mycompany.mygame.util.IabHelper$QueryInventoryFinishedListener)
                                      java.lang.String getResponseDesc(int)
                                      int getResponseCodeFromBundle(android.os.Bundle)
                                      int queryPurchases(com.mycompany.mygame.util.Inventory,java.lang.String)
                                      int querySkuDetails(java.lang.String,com.mycompany.mygame.util.Inventory,java.util.List)
                                      void logDebug(java.lang.String)

at com.mycompany.mygame.util.IabHelper.void startSetup(com.mycompany.mygame.util.IabHelper$OnIabSetupFinishedListener)(Unknown Source)
                                      void dispose()
                                      void launchPurchaseFlow(android.app.Activity,java.lang.String,int,com.mycompany.mygame.util.IabHelper$OnIabPurchaseFinishedListener,java.lang.String)
                                      boolean handleActivityResult(int,int,android.content.Intent)
                                      com.mycompany.mygame.util.Inventory queryInventory$337baa91(boolean,java.util.List)
                                      void queryInventoryAsync$69bb631c(java.util.List,com.mycompany.mygame.util.IabHelper$QueryInventoryFinishedListener)
                                      java.lang.String getResponseDesc(int)
                                      int getResponseCodeFromBundle(android.os.Bundle)
                                      int queryPurchases(com.mycompany.mygame.util.Inventory,java.lang.String)
                                      int querySkuDetails(java.lang.String,com.mycompany.mygame.util.Inventory,java.util.List)
                                      void logDebug(java.lang.String)

at com.mycompany.mygame.util.IabHelper$2.void run()(Unknown Source)
at java.lang.Thread.run(Thread.java:1019)

I'm a bit hazy about how to read stack traces, but I guess that maybe OnIabPurchaseFinishedListener had a null pointer ...? If so, how could this happen?

: , "startPurchaseFlow" , , , - ?

: :

/**
 * Callback that notifies when a purchase is finished.
 */
public interface OnIabPurchaseFinishedListener {
    /**
     * Called to notify that an in-app purchase finished. If the purchase was successful,
     * then the sku parameter specifies which item was purchased. If the purchase failed,
     * the sku and extraData parameters may or may not be null, depending on how far the purchase
     * process went.
     *
     * @param result The result of the purchase.
     * @param info The purchase information (null if purchase failed)
     */
    public void onIabPurchaseFinished(IabResult result, Purchase info);
}
+5

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