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 这是他们给我看的内容

line 156-158
1907-1931/com.example.casquejo.loginadmin E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #2 Process: com.example.casquejo.loginadmin, PID: 1907 java.lang.RuntimeException: An error occured while executing doInBackground() Caused by: 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)

谁能帮我解决这个问题，或者谁能告诉我如何解决这个问题` 下面是我的 java 类 EditProductActivity.class

       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();
        }

    }
}

最佳答案

ide指的是

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

读取值应该不是问题，但为了摆脱此警告/错误，您可以将其移至 onClick 并通过 execute() 传递值。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，你可以通过前面的params，String...args读取那些bac。三点构造保留可变参数，可变参数可以像数组一样访问，使用 [] 表示法。在示例的情况下，

args[0]包含name的值，args[1]包含price的值args[2] 包含 description 的值。

关于java - Android Studio错误: "Method getText() must be called from the UI Thread,当前推断线程是worker，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32568340/