Android Studio 无法 getApplicationContext() 到 aws

Question

我遵循 aws 指南，但收到 getApplicationContext() 的错误。

package com.example.wcyv3.stylish;

import android.content.Context;

import com.amazonaws.auth.CognitoCachingCredentialsProvider;
import com.amazonaws.regions.Regions;

public class ManagerClass {
  public CognitoCachingCredentialsProvider getCredentials() {
    CognitoCachingCredentialsProvider credentialsProvider = new CognitoCachingCredentialsProvider(
                    getApplicationContext(),// Context
                    "ap-southeast-1:xxxxxxxxxxxxxxxxxxxxxxxxxxxx", // Identity pool ID

    );

    return credentialsProvider;

  }
}

Answer 1

这是因为你的类中没有 getApplicationContext() 方法，它属于 Activity、Fragment、Application 等。为了解决这个问题，你可以通过 constructor 传递上下文或者您可以将方法设置为static，然后将上下文作为参数传递。

通过构造函数：

public class ManagerClass {

  private Context context;

  public ManagerClass(Context context) {
    this.context = context;
  }

  public CognitoCachingCredentialsProvider getCredentials() {
    CognitoCachingCredentialsProvider credentialsProvider = new CognitoCachingCredentialsProvider(
                context,
                "ap-southeast-1:xxxxxxxxxxxxxxxxxxxxxxxxxxxx", // Identity pool ID

       );

    return credentialsProvider;
  }
}

或者通过静态方法的参数：

public class ManagerClass {

  public static CognitoCachingCredentialsProvider getCredentials(Context context) {
    CognitoCachingCredentialsProvider credentialsProvider = new CognitoCachingCredentialsProvider(
                context,
                "ap-southeast-1:xxxxxxxxxxxxxxxxxxxxxxxxxxxx", // Identity pool ID

       );

    return credentialsProvider;
  }
}

Answer 2

在您的活动类中使用此方法或在方法中使用Context 类型的参数。

public CognitoCachingCredentialsProvider getCredentials(Context context){
    return new CognitoCachingCredentialsProvider (context, "ap-southeast-1:xxxxxxxxxxxxxxxxxxxxxxxxxxxx" // Identity pool ID
        );