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Android と PHP、MySQL の接続に関する次のチュートリアルに従ってみました。

http://www.androidhive.info/2012/05/how-to-connect-android-with-php-mysql/

ただし、私とチュートリアルに従っているほとんどのユーザーは、ダウンロードしたチュートリアルのソースから直接アプリケーションを実行し、いずれかのボタンをクリックすると、強制終了エラーが発生します。

(コメントセクションを見てください - ほとんどの人がこのチュートリアルで問題を抱えています)

ログキャット:

03-17 14:40:10.064: D/dalvikvm(2936): GC_CONCURRENT freed 177K, 5% free 7488K/7812K, paused 2ms+11ms, total 33ms
03-17 14:40:16.294: D/dalvikvm(2936): GC_CONCURRENT freed 80K, 4% free 7856K/8140K, paused 3ms+2ms, total 26ms
03-17 14:40:16.784: E/JSON Parser(2936): Error parsing data org.json.JSONException: Value <br of type java.lang.String cannot be converted to JSONObject
03-17 14:40:16.794: W/dalvikvm(2936): threadid=15: thread exiting with uncaught exception (group=0x41d42930)
03-17 14:40:16.794: E/AndroidRuntime(2936): FATAL EXCEPTION: AsyncTask #5
03-17 14:40:16.794: E/AndroidRuntime(2936): java.lang.RuntimeException: An error occured while executing doInBackground()
03-17 14:40:16.794: E/AndroidRuntime(2936):     at android.os.AsyncTask$3.done(AsyncTask.java:299)
03-17 14:40:16.794: E/AndroidRuntime(2936):     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:352)
03-17 14:40:16.794: E/AndroidRuntime(2936):     at java.util.concurrent.FutureTask.setException(FutureTask.java:219)
03-17 14:40:16.794: E/AndroidRuntime(2936):     at java.util.concurrent.FutureTask.run(FutureTask.java:239)
03-17 14:40:16.794: E/AndroidRuntime(2936):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1080)
03-17 14:40:16.794: E/AndroidRuntime(2936):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:573)
03-17 14:40:16.794: E/AndroidRuntime(2936):     at java.lang.Thread.run(Thread.java:856)
03-17 14:40:16.794: E/AndroidRuntime(2936): Caused by: java.lang.NullPointerException
03-17 14:40:16.794: E/AndroidRuntime(2936):     at com.example.androidhive.NewProductActivity$CreateNewProduct.doInBackground(NewProductActivity.java:98)
03-17 14:40:16.794: E/AndroidRuntime(2936):     at com.example.androidhive.NewProductActivity$CreateNewProduct.doInBackground(NewProductActivity.java:1)
03-17 14:40:16.794: E/AndroidRuntime(2936):     at android.os.AsyncTask$2.call(AsyncTask.java:287)
03-17 14:40:16.794: E/AndroidRuntime(2936):     at java.util.concurrent.FutureTask.run(FutureTask.java:234)
03-17 14:40:16.794: E/AndroidRuntime(2936):     ... 3 more
03-17 14:40:17.284: E/WindowManager(2936): Activity com.example.androidhive.NewProductActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{42488ea0 V.E..... R.....ID 0,0-296,153} that was originally added here
03-17 14:40:17.284: E/WindowManager(2936): android.view.WindowLeaked: Activity com.example.androidhive.NewProductActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView{42488ea0 V.E..... R.....ID 0,0-296,153} that was originally added here
03-17 14:40:17.284: E/WindowManager(2936):  at android.view.ViewRootImpl.<init>(ViewRootImpl.java:354)
03-17 14:40:17.284: E/WindowManager(2936):  at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:216)
03-17 14:40:17.284: E/WindowManager(2936):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
03-17 14:40:17.284: E/WindowManager(2936):  at android.app.Dialog.show(Dialog.java:281)
03-17 14:40:17.284: E/WindowManager(2936):  at com.example.androidhive.NewProductActivity$CreateNewProduct.onPreExecute(NewProductActivity.java:75)
03-17 14:40:17.284: E/WindowManager(2936):  at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:586)
03-17 14:40:17.284: E/WindowManager(2936):  at android.os.AsyncTask.execute(AsyncTask.java:534)
03-17 14:40:17.284: E/WindowManager(2936):  at com.example.androidhive.NewProductActivity$1.onClick(NewProductActivity.java:55)
03-17 14:40:17.284: E/WindowManager(2936):  at android.view.View.performClick(View.java:4204)
03-17 14:40:17.284: E/WindowManager(2936):  at android.view.View$PerformClick.run(View.java:17355)
03-17 14:40:17.284: E/WindowManager(2936):  at android.os.Handler.handleCallback(Handler.java:725)
03-17 14:40:17.284: E/WindowManager(2936):  at android.os.Handler.dispatchMessage(Handler.java:92)
03-17 14:40:17.284: E/WindowManager(2936):  at android.os.Looper.loop(Looper.java:137)
03-17 14:40:17.284: E/WindowManager(2936):  at android.app.ActivityThread.main(ActivityThread.java:5041)
03-17 14:40:17.284: E/WindowManager(2936):  at java.lang.reflect.Method.invokeNative(Native Method)
03-17 14:40:17.284: E/WindowManager(2936):  at java.lang.reflect.Method.invoke(Method.java:511)
03-17 14:40:17.284: E/WindowManager(2936):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
03-17 14:40:17.284: E/WindowManager(2936):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
03-17 14:40:17.284: E/WindowManager(2936):  at dalvik.system.NativeStart.main(Native Method)




JAVA:    NewProductActivity.java


package com.example.androidhive;

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;

public class NewProductActivity extends Activity {

// Progress Dialog
private ProgressDialog pDialog;

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

// url to create new product
private static String url_create_product =    "http://linkingmanager.zxq.net/create_product.php";

// JSON Node names
private static final String TAG_SUCCESS = "success";

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

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

    // Create button
    Button btnCreateProduct = (Button) findViewById(R.id.btnCreateProduct);

    // button click event
    btnCreateProduct.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View view) {
            // creating new product in background thread
            new CreateNewProduct().execute();
        }
    });
}

/**
 * Background Async Task to Create new product
 * */
class CreateNewProduct extends AsyncTask<String, String, String> {

    /**
     * Before starting background thread Show Progress Dialog
     * */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        pDialog = new ProgressDialog(NewProductActivity.this);
        pDialog.setMessage("Creating Product..");
        pDialog.setIndeterminate(false);
        pDialog.setCancelable(true);
        pDialog.show();
    }

    /**
     * Creating product
     * */
    protected String doInBackground(String... args) {
        String name = inputName.getText().toString();
        String price = inputPrice.getText().toString();
        String description = inputDesc.getText().toString();

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

        // getting JSON Object
        // Note that create product url accepts POST method
        JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                "POST", params);

        // check log cat fro response
        Log.d("Create Response", json.toString());

        // check for success tag
        try {
            int success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                // successfully created product
                Intent i = new Intent(getApplicationContext(), AllProductsActivity.class);
                startActivity(i);

                // closing this screen
                finish();
            } else {
                // failed to create product
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }

        return null;
    }

    /**
     * After completing background task Dismiss the progress dialog
     * **/
    protected void onPostExecute(String file_url) {
        // dismiss the dialog once done
        pDialog.dismiss();
    }

}
}


XML: add_product.xml




<?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<!-- Name Label -->
<TextView android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Product Name"
    android:paddingLeft="10dip"
    android:paddingRight="10dip"
    android:paddingTop="10dip"
    android:textSize="17dip"/>

<!-- Input Name -->
<EditText android:id="@+id/inputName"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_margin="5dip"
    android:layout_marginBottom="15dip"
    android:singleLine="true"/>

<!-- Price Label -->
<TextView android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Price"
    android:paddingLeft="10dip"
    android:paddingRight="10dip"
    android:paddingTop="10dip"
    android:textSize="17dip"/>

<!-- Input Price -->
<EditText android:id="@+id/inputPrice" 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_margin="5dip"
    android:layout_marginBottom="15dip"
    android:singleLine="true"
    android:inputType="numberDecimal"/>

<!-- Description Label -->
<TextView android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Description"
    android:paddingLeft="10dip"
    android:paddingRight="10dip"
    android:paddingTop="10dip"
    android:textSize="17dip"/>

<!-- Input description -->
<EditText android:id="@+id/inputDesc" 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_margin="5dip"
    android:layout_marginBottom="15dip"
    android:lines="4"
    android:gravity="top"/>

<!-- Button Create Product -->
<Button android:id="@+id/btnCreateProduct" 
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Create Product"/>

 </LinearLayout>



JAVA: AllProductsActivity.java


package com.example.androidhive;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import org.apache.http.NameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import android.app.ListActivity;
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.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;
import android.widget.TextView;
public class AllProductsActivity extends ListActivity {

    // Progress Dialog
    private ProgressDialog pDialog;

    // Creating JSON Parser object
    JSONParser jParser = new JSONParser();

    ArrayList<HashMap<String, String>> productsList;

    // url to get all products list
    private static String url_all_products = "http://linkingmanager.zxq.net/get_all_products.php";


    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCTS = "products";
    private static final String TAG_PID = "pid";
    private static final String TAG_NAME = "name";

    // products JSONArray
    JSONArray products = null;

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


        // Hashmap for ListView
        productsList = new ArrayList<HashMap<String, String>>();

        // Loading products in Background Thread
        new LoadAllProducts().execute();

        // Get listview
        ListView lv = getListView();

        // on seleting single product
        // launching Edit Product Screen
        lv.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                // getting values from selected ListItem
                String pid = ((TextView) view.findViewById(R.id.pid)).getText()
                        .toString();

                // Starting new intent
                Intent in = new Intent(getApplicationContext(),
                        EditProductActivity.class);
                // sending pid to next activity
                in.putExtra(TAG_PID, pid);

                // starting new activity and expecting some response back
                startActivityForResult(in, 100);
            }
        });

    }

    // Response from Edit Product Activity
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        // if result code 100
        if (resultCode == 100) {
            // if result code 100 is received 
            // means user edited/deleted product
            // reload this screen again
            Intent intent = getIntent();
            finish();
            startActivity(intent);
        }

    }

    /**
     * Background Async Task to Load all product by making HTTP Request
     * */
    class LoadAllProducts extends AsyncTask<String, String, String> {

        /**
         * Before starting background thread Show Progress Dialog
         * */
        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            pDialog = new ProgressDialog(AllProductsActivity.this);
            pDialog.setMessage("Loading products. Please wait...");
            pDialog.setIndeterminate(false);
            pDialog.setCancelable(false);
            pDialog.show();
        }

        /**
         * getting All products from url
         * */
        protected String doInBackground(String... args) {
            // Building Parameters
            List<NameValuePair> params = new ArrayList<NameValuePair>();
            // getting JSON string from URL
            JSONObject json = jParser.makeHttpRequest(url_all_products, "GET", params);

            // Check your log cat for JSON reponse
            Log.d("All Products: ", json.toString());

            try {
                // Checking for SUCCESS TAG
                int success = json.getInt(TAG_SUCCESS);

                if (success == 1) {
                    // products found
                    // Getting Array of Products
                    products = json.getJSONArray(TAG_PRODUCTS);

                    // looping through All Products
                    for (int i = 0; i < products.length(); i++) {
                        JSONObject c = products.getJSONObject(i);

                        // Storing each json item in variable
                        String id = c.getString(TAG_PID);
                        String name = c.getString(TAG_NAME);

                        // creating new HashMap
                        HashMap<String, String> map = new HashMap<String, String>();

                        // adding each child node to HashMap key => value
                        map.put(TAG_PID, id);
                        map.put(TAG_NAME, name);

                        // adding HashList to ArrayList
                        productsList.add(map);
                    }
                } else {
                    // no products found
                    // Launch Add New product Activity
                    Intent i = new Intent(getApplicationContext(),
                            NewProductActivity.class);
                    // Closing all previous activities
                    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                    startActivity(i);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

            return null;
        }

        /**
         * After completing background task Dismiss the progress dialog
         * **/
        protected void onPostExecute(String file_url) {
            // dismiss the dialog after getting all products
            pDialog.dismiss();
            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    /**
                     * Updating parsed JSON data into ListView
                     * */
                    ListAdapter adapter = new SimpleAdapter(
                            AllProductsActivity.this, productsList,
                            R.layout.list_item, new String[] { TAG_PID,
                                    TAG_NAME},
                            new int[] { R.id.pid, R.id.name });
                    // updating listview
                    setListAdapter(adapter);
                }
            });

        }

    }
}


XML: all_products.xml



<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<!-- Main ListView 
     Always give id value as list(@android:id/list)
-->
<ListView
    android:id="@android:id/list"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"/>

</LinearLayout>
4

1 に答える 1

0
Caused by: java.lang.NullPointerException
03-17 14:40:16.794: E/AndroidRuntime(2936):     at com.example.androidhive.NewProductActivity$CreateNewProduct.doInBackground(NewProductActivity.java:98)

私が間違っていなければ、それはこの行です

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

つまり、何らかの理由でここでnullを取得します

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

おそらくあなたのURLは間違っています。

于 2013-03-17T19:15:19.087 に答える