Question

我有从外部JSON数组接收变量的代码

import java.io.IOException;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.widget.Toast;

public class ListviewActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        String json_str = getJsonData();

        try{
            JSONArray jArray = new JSONArray(json_str);

                JSONObject json = null;
                json = jArray.getJSONObject(0);

               String date=json.getString("data");

            Toast.makeText(getBaseContext(), date, Toast.LENGTH_SHORT).show();

        } catch ( JSONException e) {
            e.printStackTrace();
        }

    }

    private String getJsonData(){
        StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
                .detectDiskReads()
                .detectDiskWrites()
                .detectNetwork()
                .penaltyLog()
                .build());

        String str = "";
        HttpResponse response;
        HttpClient myClient = new DefaultHttpClient();
        HttpPost myConnection = new HttpPost("url_php_file_with_JSON");

        try {
            response = myClient.execute(myConnection);
            str = EntityUtils.toString(response.getEntity(), "UTF-8");

        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }

        return str;
    }
}

//comparison variable (from String date=json.getString("data")) with an other static variable

如何正确显示变量String date = json.getString（“data”）以便在其他函数中进行比较？

虽然它在使用Toast.makeText接收变量的函数中显示，但我必须在java文件的其他区域中使用它

Answer 1

您需要将String设为全局变量，如下所示：

public class ListviewActivity extends Activity {

    private String date;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        String json_str = getJsonData();

        try{
            JSONArray jArray = new JSONArray(json_str);

                JSONObject json = null;
                json = jArray.getJSONObject(0);

               date=json.getString("data");

            Toast.makeText(getBaseContext(), date, Toast.LENGTH_SHORT).show();

        } catch ( JSONException e) {
            e.printStackTrace();
        }

    }

    // The rest of your code
}

这样，您可以在班级的任何地方自由使用它。

如何从JSONArray传递变量

1 个答案: