Question

我正在使用AsyncHttpClient类，我无法将结果保存为OnSuccess函数中的字符串。下面是我要解析的结果示例，我正在尝试检索“lsoa”值。

{
"status" : 200,
"result" : {
    "postcode" : "NW2 1SJ",
    "quality" : 1,
    "eastings" : 524332,
    "northings" : 186558,
    "country" : "England",
    "nhs_ha" : "London",
    "longitude" : -0.207661046004569,
    "latitude" : 51.5642021415348,
    "parliamentary_constituency" : "Finchley and Golders Green",
    "european_electoral_region" : "London",
    "primary_care_trust" : "Barnet",
    "region" : "London",
    "lsoa" : "Barnet 040A",
    "msoa" : "Barnet 040",
    "incode" : "1SJ",
    "outcode" : "NW2",
    "admin_district" : "Barnet",
    "parish" : "Barnet, unparished area",
    "admin_county" : null,
    "admin_ward" : "Childs Hill",
    "ccg" : "NHS Barnet",
    "nuts" : "Barnet",
    "codes" : {
        "admin_district" : "E09000003",
        "admin_county" : "E99999999",
        "admin_ward" : "E05000045",
        "parish" : "E43000193",
        "ccg" : "E38000005",
        "nuts" : "UKI71"
    }
}

我想要做的就是将API中的“lsoa”存储到一个字符串中，但我甚至无法将整个输出分配给一个字符串，因为我得到一个“变量's是从内部类中访问，需要声明最终“错误。

private void queryPostcodes(String searchString){

        String s;
        // Create a client to perform API request
        AsyncHttpClient client = new AsyncHttpClient();

        mDialog.show();

        // Output the link being checked
        Log.d("Gentrification: ", QUERY_URL + searchString);

        // Have the client get a JSONArray of data and define how to respond
        client.get(QUERY_URL + searchString, new JsonHttpResponseHandler(){

            @Override
            public void onSuccess(JSONObject jsonObject){
                mDialog.dismiss();
                Log.d("X: ", jsonObject.toString());
                s = jsonObject.toString(); //<-- DOESN'T WORK :(
            }

            @Override
            public void onFailure(int statusCode, Throwable throwable, JSONObject error){
                mDialog.dismiss();
                Toast.makeText(getApplicationContext(), "Error: " + statusCode + " " + throwable.getMessage() + " - Postcode not found", Toast.LENGTH_LONG).show();
                Log.e("X", statusCode + " " + throwable.getMessage());

            }
        });
    }

非常感谢任何帮助。

Answer 1

如果您尝试在AndroidStudio中按Alt + Enter，您将获得一个quickfix选项：“将'转换为'转换为一个元素数组'。点击并瞧瞧。

问题的原因是new JsonHttpResponseHandler()创建了匿名内部类的新实例。您要从内部访问的所有内容都应声明为父类的字段或包含方法的最终变量。另一方面，你不能使你的字符串最终，因为最终变量只被分配一次。您可以使用单个String参数创建包装类，或者使's'成为父类的字段，或者使用String []作为包装。

String wrapper选项：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final StringBuffer stringBuffer = new StringBuffer();
        Button updateButton = (Button) findViewById(R.id.update);
        updateButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                stringBuffer
                        .delete(0, stringBuffer.length())
                        .append(System.currentTimeMillis());
            }
        });
    }
}

父选项字段：

public class MainActivity extends AppCompatActivity {

    private String s;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button updateButton = (Button) findViewById(R.id.update);
        updateButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                s = String.valueOf(System.currentTimeMillis());
            }
        });
    }
}

String []选项：

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final String[] s = new String[1];
        Button updateButton = (Button) findViewById(R.id.update);
        updateButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                s[0] = String.valueOf(System.currentTimeMillis());
            }
        });
    }
}

Android Postcodes.io HTTP请求

1 个答案: