Android 应用内购买计费客户端在构建时崩溃

Question

我是 Android 应用内购买的新手。 我遵循了官方文档，除了构建 BillingClient 之外，我无法 go 因为应用程序在尝试构建 BillingClient 时崩溃。 非常感谢 Java 中对 android 应用内购买的任何帮助或任何参考。 我的 MainActivity.java 代码如下：

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.webkit.WebSettings;
import android.webkit.WebView;

import com.android.billingclient.api.BillingClient;
import com.android.billingclient.api.BillingClientStateListener;
import com.android.billingclient.api.BillingResult;
import com.android.billingclient.api.Purchase;
import com.android.billingclient.api.PurchasesUpdatedListener;
import java.util.List;

public class MainActivity extends AppCompatActivity{

    private PurchasesUpdatedListener purchaseUpdateListener = new PurchasesUpdatedListener() {
        @Override
        public void onPurchasesUpdated(BillingResult billingResult, List<Purchase> purchases) {
            // To be implemented in a later section.
        }
    };


    private BillingClient billingClient = BillingClient.newBuilder(MainActivity.this)
            .setListener(purchaseUpdateListener)
            .enablePendingPurchases()
            .build();


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

}

崩溃日志如下：

2020-07-07 01:19:40.667 27956-27956/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.js.bs, PID: 27956
    java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.js.bs/com.js.bs.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3272)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3500)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2049)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:223)
        at android.app.ActivityThread.main(ActivityThread.java:7523)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.Context android.content.Context.getApplicationContext()' on a null object reference
        at android.content.ContextWrapper.getApplicationContext(ContextWrapper.java:122)
        at com.android.billingclient.api.BillingClientImpl.initialize(com.android.billingclient:billing@@3.0.0:26)
        at com.android.billingclient.api.BillingClientImpl.<init>(com.android.billingclient:billing@@3.0.0:13)
        at com.android.billingclient.api.BillingClientImpl.<init>(com.android.billingclient:billing@@3.0.0:1)
        at com.android.billingclient.api.BillingClient$Builder.build(com.android.billingclient:billing@@3.0.0:14)
        at com.js.bs.MainActivity.<init>(MainActivity.java:31)
        at java.lang.Class.newInstance(Native Method)
        at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95)
        at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:41)
        at android.app.Instrumentation.newActivity(Instrumentation.java:1253)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3260)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3500) 
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83) 
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2049) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loop(Looper.java:223) 
        at android.app.ActivityThread.main(ActivityThread.java:7523) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:941) 
2020-07-07 01:19:41.044 27956-27956/? I/Process: Sending signal. PID: 27956 SIG: 9

Answer 1

请更改billingClient object 创建如下。 虽然从context外部创建这个 object 可能是 null，所以崩溃了。 将 object 创建移动到活动的onCreate()方法。

    private BillingClient billingClient;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        billingClient = BillingClient.newBuilder(this)
            .setListener(purchaseUpdateListener)
            .enablePendingPurchases()
            .build();
    }