Question

 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_expenses__add);
    amount = (EditText) findViewById(R.id.et_amount);
    date1 = (EditText) findViewById(R.id.date);
    button = (Button) findViewById(R.id.btn_add);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            amount1 = amount.getText().toString();
            SimpleDateFormat formatter = new SimpleDateFormat("dd-MM-yyyy");
            String dateInString = date1.getText().toString();
            try {

                Date date = formatter.parse(dateInString);
                myText=formatter.format(date);
            }
            catch (ParseException e) {
                e.printStackTrace();
            }
            Toast.makeText(Expenses_Add.this,myText,Toast.LENGTH_LONG).show();
        }
    });
    RequestQueue requestQueue = Volley.newRequestQueue(Expenses_Add.this);
    StringRequest stringRequest = new StringRequest(Request.Method.POST, url, new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {
        }
    }

    ) {
        protected Map<String, String> getParams() {
            Map<String, String> params = new HashMap<String, String>();

            params.put("date",String.valueOf( myText));
            params.put("email", "bdshah437@gmail.com");
            params.put("amount", amount1);

            return params;
        }
    };

        requestQueue.add(stringRequest);
}    protected void onStart() {
    super.onStart();
    EditText editText = (EditText) findViewById(R.id.date);
    editText.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View view, boolean b) {
            if (b) {
                DateDialog dateDialog = new DateDialog(view);
                android.app.FragmentTransaction ft = getFragmentManager().beginTransaction();

                dateDialog.show(ft, "DatePicker");
            }
        }
    });
}
}

有错误

09-11 04：20：48.006 16973-17061 / com.example.bhoomi.household E / Volley： [42344] NetworkDispatcher.run：未处理的异常显示java.lang.NullPointerException 显示java.lang.NullPointerException 在libcore.net.UriCodec.encode（UriCodec.java:132）在java.net.URLEncoder.encode（URLEncoder.java:57）在com.android.volley.Request.encodeParameters（Request.java:450）在com.android.volley.Request.getBody（Request.java:436）在 com.android.volley.toolbox.HurlStack.addBodyIfExists（HurlStack.java:260）在 com.android.volley.toolbox.HurlStack.setConnectionParametersForRequest（HurlStack.java:234）在 com.android.volley.toolbox.HurlStack.performRequest（HurlStack.java:107）在 com.android.volley.toolbox.BasicNetwork.performRequest（BasicNetwork.java:96）在 com.android.volley.NetworkDispatcher.run（NetworkDispatcher.java:112）

Answer 1

创建新的MySingleton类

 public class MySingleton{
        private static MySingleton mInstance;
        private RequestQueue mRequestQueue;
        private ImageLoader mImageLoader;
        private static Context mCtx;

        private MySingleton(Context context) {
            mCtx = context;
            mRequestQueue = getRequestQueue();

            mImageLoader = new ImageLoader(mRequestQueue,
                    new ImageLoader.ImageCache() {
                        private final LruCache<String, Bitmap>
                                cache = new LruCache<String, Bitmap>(20);

                        @Override
                        public Bitmap getBitmap(String url) {
                            return cache.get(url);
                        }

                        @Override
                        public void putBitmap(String url, Bitmap bitmap) {
                            cache.put(url, bitmap);
                        }
                    });
        }

        public static synchronized MySingleton getInstance(Context context) {
            if (mInstance == null) {
                mInstance = new MySingleton(context);
            }
            return mInstance;
        }

        public RequestQueue getRequestQueue() {
            if (mRequestQueue == null) {
                // getApplicationContext() is key, it keeps you from leaking the
                // Activity or BroadcastReceiver if someone passes one in.
                mRequestQueue = Volley.newRequestQueue(mCtx.getApplicationContext());
            }
            return mRequestQueue;
        }

        public <T> void addToRequestQueue(Request<T> req) {
            getRequestQueue().add(req);
        }

        public ImageLoader getImageLoader() {
            return mImageLoader;
        }

        public void cancelPendingRequests(Object tag) {
            if (mRequestQueue != null) {
                mRequestQueue.cancelAll(tag);
            }
        }
    }

要求点击按钮

StringRequest stringRequest = new StringRequest(Request.Method.POST,url,
                    new Response.Listener<String>() {
                        @Override
                        public void onResponse(String response) {
                            Log.d("---response--", "" + response);
                        }
                    },
                    new Response.ErrorListener() {
                        @Override
                        public void onErrorResponse(VolleyError error) {
                            Log.d("error---", "" + error.toString());
                        }
                    }) {
                @Override
                protected Map<String, String> getParams() {
                    Map<String, String> params = new HashMap<String, String>();

                    params.put("date",String.valueOf( myText));
                    params.put("email", "bdshah437@gmail.com");
                    params.put("amount", amount1);

                    return params;
                }
            };
            MySingleton.getInstance(Expenses_Add.this).addToRequestQueue(stringRequest);

凌空中的例外情况

1 个答案: