我正在开发，我想要显示用户登录。以下是我的代码，它在Logcat中显示正确的响应，但未在应用程序端显示消息（即登录成功或登录失败消息）。我该怎么做呢？
我如何在此解析json数据？
请建议我!!
//以下是来自Logcat
{
"login": [
{
"sessionid": 12973,
"responsetypes": "success"
}
]
}
//以下是我的代码
public class LoginActivity extends AppCompatActivity implements View.OnClickListener {
private EditText usernameEditText;
private EditText passwordEditText;
private Button sendGetReqButton;
TextView tv_forgot;
Button register;
Toolbar toolbar;
private boolean loggedIn = false;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
tv_forgot= (TextView)findViewById(R.id.tv_forgot);
tv_forgot.setOnClickListener(this);
usernameEditText = (EditText) findViewById(R.id.ed_email);
passwordEditText = (EditText) findViewById(R.id.ed_passowrd);
register = (Button) findViewById(R.id.btn_reg);
sendGetReqButton = (Button) findViewById(R.id.btn_login);
sendGetReqButton.setOnClickListener(this);
}
@Override
public void onClick(View v) {
if(v.getId() == R.id.btn_login){
// Get the values given in EditText fields
String userID = usernameEditText.getText().toString();
String password = passwordEditText.getText().toString();
System.out.println("Givennames is :" + userID + " Given password is :" + password);
// Pass those values to connectWithHttpGet() method
connectWithHttpGet(userID, password);
}
else {
Toast.makeText(LoginActivity.this, "Please Fill the fields", Toast.LENGTH_LONG).show();
}
}
private void connectWithHttpGet(String userID, String password) {
// Connect with a server is a time consuming process.
//Therefore we use AsyncTask to handle it
// From the three generic types;
//First type relate with the argument send in execute()
//Second type relate with onProgressUpdate method which I haven't use in this code
//Third type relate with the return type of the doInBackground method, which also the input type of the onPostExecute method
class HttpGetAsyncTask extends AsyncTask<String, Void, String> {
@Override
protected String doInBackground(String... params) {
// As you can see, doInBackground has taken an Array of Strings as the argument
//We need to specifically get the givenUsername and givenPassword
String paramUsername = params[0];
String paramPassword = params[1];
System.out.println("userID" + paramUsername + " password is :" + paramPassword);
// Create an intermediate to connect with the Internet
HttpClient httpClient = new DefaultHttpClient();
// Sending a GET request to the web page that we want
// Because of we are sending a GET request, we have to pass the values through the URL
HttpGet httpGet = new HttpGet("http://www.example.com/ypAndroid/api/doLogin?userID=" + paramUsername + "&password=" + paramPassword);
try {
// execute(); executes a request using the default context.
// Then we assign the execution result to HttpResponse
HttpResponse httpResponse = httpClient.execute(httpGet);
System.out.println("httpResponse// getEntity() ; obtains the message entity of this response");
// getContent() ; creates a new InputStream object of the entity.
// Now we need a readable source to read the byte stream that comes as the httpResponse
InputStream inputStream = httpResponse.getEntity().getContent();
// We have a byte stream. Next step is to convert it to a Character stream
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
// Then we have to wraps the existing reader (InputStreamReader) and buffer the input
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
// InputStreamReader contains a buffer of bytes read from the source stream and converts these into characters as needed.
//The buffer size is 8K
//Therefore we need a mechanism to append the separately coming chunks in to one String element
// We have to use a class that can handle modifiable sequence of characters for use in creating String
StringBuilder stringBuilder = new StringBuilder();
String bufferedStrChunk = null;
// There may be so many buffered chunks. We have to go through each and every chunk of characters
//and assign a each chunk to bufferedStrChunk String variable
//and append that value one by one to the stringBuilder
while((bufferedStrChunk = bufferedReader.readLine()) != null){
stringBuilder.append(bufferedStrChunk);
}
// Now we have the whole response as a String value.
//We return that value then the onPostExecute() can handle the content
System.out.println("Returninge of doInBackground :" + stringBuilder.toString());
// If the Username and Password match, it will return "working" as response
// If the Username or Password wrong, it will return "invalid" as response
return stringBuilder.toString();
} catch (ClientProtocolException cpe) {
System.out.println("Exceptionrates caz of httpResponse :" + cpe);
cpe.printStackTrace();
} catch (IOException ioe) {
System.out.println("Secondption generates caz of httpResponse :" + ioe);
ioe.printStackTrace();
}
return null;
}
// Argument comes for this method according to the return type of the doInBackground() and
//it is the third generic type of the AsyncTask
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
System.out.println("Post result :" + result);
if(result.equals("success"))
Toast.makeText(getApplicationContext(), "HTTP GET is working...", Toast.LENGTH_LONG).show();
else {
Toast.makeText(getApplicationContext(), "Invalid...", Toast.LENGTH_LONG).show();
}
}
}
// Initialize the AsyncTask class
HttpGetAsyncTask httpGetAsyncTask = new HttpGetAsyncTask();
// Parameter we pass in the execute() method is relate to the first generic type of the AsyncTask
// We are passing the connectWithHttpGet() method arguments to that
httpGetAsyncTask.execute(userID, password);
}
}
答案 0 :(得分：0)
例如方法获取错误响应使用volley。
private void getLogin() {
JSONObject param = new JSONObject();
try {
param.put("username", username.getText().toString());
param.put("password", password.getText().toString());
} catch (JSONException e) {
e.printStackTrace();
}
JsonObjectRequest jsonObjectRequest = new JsonObjectRequest(
Request.Method.POST, url, param, new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
try {
JSONArray jsonArray = response.getJSONArray("login");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject = jsonArray.getJSONObject(i);
Log.d("sessionid>> ", jsonObject.getString("sessionid"));
}
dissmissPDialog();
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Log.d("error >> ", error.toString());
streror = error.toString();
dissmissPDialog();
}
}
);
normal.add(jsonObjectRequest);
}
答案 1 :(得分：0)
你可以这样做。
在onPostExecute()方法
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
System.out.println("Post result :" + result);
try {
JSONObject jsonObject = new JSONObject(result);
JSONArray login = jsonObject.getJSONArray("login");
JSONObject jsonObject1 = login.getJSONObject(0);
// edited second, you response was responsetype, but I parsed was responsetypes,so you can have a look.
String responsetypes = jsonObject1.optString("responsetypes");
// edited
String sessionid = jsonObject1.getString("sessionid");
if (TextUtils.equals(responsetypes, "success")) {
Toast.makeText(getApplicationContext(), "HTTP GET is working...", Toast.LENGTH_LONG).show();
} else if (TextUtils.equals(responsetypes, "failure")) {
// edited
String message = jsonObject1.getString("message");
Toast.makeText(getApplicationContext(), message, Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
答案 2 :(得分：0)
像这样更新您的onPostExecute()方法。
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
try {
JSONObject jsonObject1 = new JSONObject(result);
JSONArray jsonArray = jsonObject1.getJSONArray("login");
JSONObject jsonObjectLogin = jsonArray.getJSONObject(0);
String response = jsonObjectLogin.getString("responsetypes");
Toast.makeText(getApplicationContext(), +response, Toast.LENGTH_LONG).show();
} catch (JSONException e) {
e.printStackTrace();
}
}
让我知道这是否有效。