Android Studio错误:"必须从UI线程调用方法getText(),当前推断的线程是worker

Question

我正在android studio中创建一个CRUD操作,但我不断收到错误.错误是当我检查LogCat这是他们告诉我的

156-158
1907-1931/com.example.casquejo.loginadmin E/AndroidRuntime:FATAL EXCEPTION:AsyncTask#2进程:com.example.casquejo.loginadmin,PID:1907 java.lang.RuntimeException:执行doInBackground时发生错误()引起:java.lang.NullPointerException atcom.example.casquejo.loginadmin.NewProductActivity $ CreateNewProduct.doInBackground(NewProductActivity.java:85)at com.example.casquejo.loginadmin.NewProductActivity $ CreateNewProduct.doInBackground(NewProductActivity.java:58 )atcom.example.casquejo.loginadmin.NewProductActivity $ CreateNewProduct.onPreExecute(NewProductActivity.java:67)atcom.example.casquejo.loginadmin.NewProductActivity $ 1.onClick(NewProductActivity.java:53)

有人可以帮我这个或者有人可以提出一个想法如何解决这个问题下面是我的java类EditProductActivity.class的代码

       package com.example.casquejo.loginadmin;

        import java.util.ArrayList;
        import java.util.List;
        import org.apache.http.NameValuePair;
        import org.apache.http.message.BasicNameValuePair;
        import org.json.JSONException;
        import org.json.JSONObject;
        import android.app.Activity;
        import android.app.ProgressDialog;
        import android.content.Intent;
        import android.os.AsyncTask;
        import android.os.Bundle;
        import android.util.Log;
        import android.view.View;
        import android.widget.Button;
        import android.widget.EditText;

        /**
        * Created by Casquejo on 9/14/2015.
        */
        public class NewProductActivity extends Activity {
    private ProgressDialog pDialog;

    JSONParser jsonParser = new JSONParser();
    EditText inputName;
    EditText inputPrice;
    EditText inputDesc;

    private static String url_create_product = "http://10.0.2.2/android_connect/create_product.php";

    private static final String TAG_SUCCESS = "success";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.add_product);

        inputName = (EditText) findViewById(R.id.inputName);
        inputPrice = (EditText) findViewById(R.id.inputPrice);
        inputDesc = (EditText) findViewById(R.id.inputDesc);

        Button btnCreateProduct = (Button) findViewById(R.id.btnCreateProduct);
        btnCreateProduct.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                String name = inputName.getText().toString();
                String price = inputPrice.getText().toString();
                String description = inputDesc.getText().toString();
                new CreateNewProduct().execute(name, price,description);
            }
        });
    }

    class CreateNewProduct extends AsyncTask<String, String, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(NewProductActivity.this);
            pDialog.setMessage("Creating Product..");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(true);
            pDialog.show();

        }

        protected String doInBackground(String... args) {

            String name = args[0],
                    price = args[1],
                    description = args[2];

            List<NameValuePair> params = new ArrayList<NameValuePair>();
            params.add(new BasicNameValuePair("name", name));
            params.add(new BasicNameValuePair("price", price));
            params.add(new BasicNameValuePair("description", description));

            JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                    "POST", params);

            Log.d("Create Response", json.toString());

            try {
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
                    startActivity(i);
                    finish();
                }
                else {

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

            return null;
        }

        protected void onPostExecute(String file_url) {
            pDialog.dismiss();
        }

    }
}

Answer 1

ide指的是

  String name = txtName.getText().toString();
  String price = txtPrice.getText().toString();
  String description = txtDesc.getText().toString();

读取值不应该是一个问题,但为了摆脱这个警告/错误,您可以将其移入onClick并传递值execute().例如

btnSave.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View arg0) {
        String name = txtName.getText().toString();
        String price = txtPrice.getText().toString();
        String description = txtDesc.getText().toString();
        new SaveProductDetails().execute(name, price, description);
    }
});

当doInBackground被调用时,你可以通过前params读取那些bac String... args.三个点构造保留为varargs,并且varargs可以像数组一样使用[]符号进行访问.在示例的情况下,

args[0]包含值name,args[1]包含值price和args[2]包含的值description.

Answer 2

你是getText()从一个后台线程调用的AsyncTask.

首先获取文本,然后调用异步任务.这是一个例子

new SaveProductDetails()
    .execute(txtName.getText().toString(), 
        txtPrice.getText().toString(), 
        txtDesc.getText().toString());

而且SaveProductDetails doInBackground方法内部:

String name = args[0],
       price = args[1],
       description = args[2];