Question

我已经在stackoverflow中阅读了一些q＆amp; a，但仍然无法使其正常工作。 Admob on Multiple Activities?

与上述解决方案类似，我收到以下错误

android.content.res.Resources android.content.Context.getResources()' on a null object reference

在这一行

 AdView adView = new AdView(this);

任何人都可以找出它发生的原因吗？

CommonCode.java

public class CommonCode extends AppCompatActivity{
//private AdView mAdView;

public void createAdview(){
    AdView adView = new AdView(this);
    adView.setAdSize(AdSize.SMART_BANNER);
    adView.setAdUnitId("ca-app-pub-3940256099942544/6300978111");

    AdRequest adRequest = new AdRequest.Builder().build();
    adView.loadAd(adRequest);
}}

MainActivity.java

public class MainActivity extends AppCompatActivity {

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

    CommonCode cc = new CommonCode();
    cc.createAdview();}}

Answer 1

您将AppCompatActivity中的CommonCode扩展为将CommonCode定义为Activity.Activity上下文为null，直到它开始。您需要从CommonCode类中删除extnds AppCompatActivity并在参数中传递上下文：

public class CommonCode{

    public void createAdview(Context context){
        AdView adView = new AdView(context);
        adView.setAdSize(AdSize.SMART_BANNER);
        adView.setAdUnitId("ca-app-pub-3940256099942544/6300978111");

        AdRequest adRequest = new AdRequest.Builder().build();
        adView.loadAd(adRequest);
    }
}

现在在MainActivity中你需要调用这样的方法：

public class MainActivity extends AppCompatActivity {

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

        CommonCode cc = new CommonCode();
        cc.createAdview(this);
    }
}

Answer 2

您需要在此行中传递活动上下文

login_email

像这样创建公共类

AdView adView = new AdView(this);

并在您的活动中使用它

public class CommonCode {
public CommonCode (){
}
public void createAdview(Context context){
AdView adView = new AdView(context);
adView.setAdSize(AdSize.SMART_BANNER);
adView.setAdUnitId("ca-app-pub-3940256099942544/6300978111");
AdRequest adRequest = new AdRequest.Builder().build();
adView.loadAd(adRequest);
}}

NullObjectReference for Admob在不同的活动中

2 个答案: