在Android中从MYSQL数据库查看所有信息时出错

debugcn 发表于 Dev

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在AllProductActivity.java中，以列表形式查看数据。在onItemClick上，取决于pid数据，移至下一个EditProductActivity。

以下代码在eclipse中工作正常，但不幸的是，在Android Studio中工作时，该活动已停止。为什么我只要有人知道就不明白。

请帮我。

AllProductActivity.java

  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://192.168.1.2/android_connect/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);
                    }
                });

            }

        }
    }

EditProductActivity.java

 public class EditProductActivity extends Activity {

    EditText txtName;
    EditText txtPrice;
    EditText txtDesc;
    EditText txtCreatedAt;
    Button btnSave;
    Button btnDelete;

    String pid;

    // Progress Dialog
    private ProgressDialog pDialog;

    // JSON parser class
    JSONParser jsonParser = new JSONParser();

    // single product url
    private static final String url_product_detials = "http://192.168.1.2/android_connect/get_product_details.php";


    // JSON Node names
    private static final String TAG_SUCCESS = "success";
    private static final String TAG_PRODUCT = "product";
    private static final String TAG_PID = "pid";
    private static final String TAG_NAME = "name";
    private static final String TAG_PRICE = "price";
    private static final String TAG_DESCRIPTION = "description";

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

        // save button
        btnSave = (Button) findViewById(R.id.btnSave);
        btnDelete = (Button) findViewById(R.id.btnDelete);

        // getting product details from intent
        Intent i = getIntent();

        // getting product id (pid) from intent
        pid = i.getStringExtra(TAG_PID);

        // Getting complete product details in background thread
        new GetProductDetails().execute();

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

            @Override
            public void onClick(View arg0) {
                // starting background task to update product

            }
        });

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

            @Override
            public void onClick(View arg0) {
                // deleting product in background thread

            }
        });

    }

    /**
     * Background Async Task to Get complete product details
     */
    class GetProductDetails extends AsyncTask<String, String, String> {

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

        /**
         * Getting product details in background thread
         */
        protected String doInBackground(String... params) {

            // updating UI from Background Thread
            runOnUiThread(new Runnable() {
                public void run() {
                    // Check for success tag
                    int success;
                    try {
                        // Building Parameters
                        List<NameValuePair> params = new ArrayList<NameValuePair>();
                        params.add(new BasicNameValuePair("pid", pid));

                        // getting product details by making HTTP request
                        // Note that product details url will use GET request
                        JSONObject json = jsonParser.makeHttpRequest(
                                url_product_detials, "GET", params);

                        // check your log for json response
                        Log.d("Single Product Details", json.toString());

                        // json success tag
                        success = json.getInt(TAG_SUCCESS);
                        if (success == 1) {
                            // successfully received product details
                            JSONArray productObj = json
                                    .getJSONArray(TAG_PRODUCT); // JSON Array

                            // get first product object from JSON Array
                            JSONObject product = productObj.getJSONObject(0);

                            // product with this pid found
                            // Edit Text
                            txtName = (EditText) findViewById(R.id.inputName);
                            txtPrice = (EditText) findViewById(R.id.inputPrice);
                            txtDesc = (EditText) findViewById(R.id.inputDesc);

                            // display product data in EditText
                            txtName.setText(product.getString(TAG_NAME));
                            txtPrice.setText(product.getString(TAG_PRICE));
                            txtDesc.setText(product.getString(TAG_DESCRIPTION));

                        } else {
                            // product with pid not found
                        }
                    } 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 got all details
            pDialog.dismiss();
        }
    }

}

Logcat错误：-

Process: info.androidhive.androidphpconnection, PID: 10068
android.os.NetworkOnMainThreadException
at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:110)
at libcore.io.IoBridge.connectErrno(IoBridge.java:137)
at libcore.io.IoBridge.connect(IoBridge.java:122)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:183)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:452)
at java.net.Socket.connect(Socket.java:884)
at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:124)
at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:149)
at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:169)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:124)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:366)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:560)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:492)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:470)
at info.androidhive.androidphpconnection.JSONParser.makeHttpRequest(JSONParser.java:62)
at info.androidhive.androidphpconnection.EditProductActivity$GetProductDetails$1.run(EditProductActivity.java:131)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

巴拉特什

原因：在UI线程上调用网络东西。这条线

JSONObject json = jsonParser.makeHttpRequest(
                                url_product_detials, "GET", params);

1.runOnUiThread在UI线程上运行，您永远不会在其中创建HTTP /网络东西。
2. doInBackGround在工作线程上运行，您可以在其中创建http / networking东西。
3.无需runOnUiThread在内部调用onPreExecute，onPostExecute因为这些方法仅在UI线程上运行。

您的代码更改是这样的。

   protected String doInBackground(String... args) {
    // Check for success tag
    try {
        // Building Parameters
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("pid", pid));

        final JSONObject json = jsonParser.makeHttpRequest(
                url_product_detials, "GET", params);

        final int success = json.getInt(TAG_SUCCESS);
        //below code runs on UI thread.
        runOnUiThread(new Runnable() {
            public void run() {
                if (success == 1) {
                    // successfully received product details
                    try {
                        JSONArray productObj = json.getJSONArray(TAG_PRODUCT); // JSON Array

                        // get first product object from JSON Array
                        JSONObject product = productObj.getJSONObject(0);

                        // product with this pid found
                        // Edit Text
                        txtName = (EditText) findViewById(R.id.inputName);
                        txtPrice = (EditText) findViewById(R.id.inputPrice);
                        txtDesc = (EditText) findViewById(R.id.inputDesc);

                        // display product data in EditText
                        txtName.setText(product.getString(TAG_NAME));
                        txtPrice.setText(product.getString(TAG_PRICE));
                        txtDesc.setText(product.getString(TAG_DESCRIPTION));
                    } catch (JSONException e) {

                    }


                } else {
                    // product with pid not found
                }
            }
        });
    } catch (JSONException e) {
        e.printStackTrace();
    }
    return null;
}

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