当我进行离线登录时，我的应用程序正在崩溃...并显示错误
Attempt to invoke virtual method 'java.lang.String org.json.JSONObject.getString(java.lang.String)' on a null object reference
在网上它工作正常没有问题，但在离线状态下崩溃根本没有给出问题的地方请帮助我
public class MainActivity extends AppCompatActivity {
**// Initializing variables**
EditText login;
EditText password;
String statusRes;
String id;
String projectName;
String loginValue;
String stockPoint;
JSONObject myRespObject = null;
public static final String Passkey = "passKey";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setTitle("LOGIN");
setContentView(R.layout.login);
login = (EditText) findViewById(R.id.loginname);
password = (EditText) findViewById(R.id.Password);
final Button saveme = (Button) findViewById(R.id.save);
**SharedPreferences sharedpreferences = getSharedPreferences(AppConstants.MyPREFERENCES, Context.MODE_PRIVATE);
saveme.setOnClickListener(new Button.OnClickListener() {
public URL url;
public void onClick(android.view.View v) {
if (!CheckNetwork.isInternetAvailable(MainActivity.this){
if (!validate()) {
onLoginFailed();
return;
}
SharedPreferences prefs = getSharedPreferences(AppConstants.MyPREFERENCES, Context.MODE_PRIVATE);
String loginValue = prefs.getString(AppConstants.LOGIN_VALUE, "");
String Passkey = prefs.getString(AppConstants.PASS_KEY, "");
String Internet = prefs.getString("Internet", "false");
String projectName = prefs.getString(AppConstants.PROJECT_NAME, "");
String stockPoint = prefs.getString(String.valueOf(AppConstants.STOCK_POINT),"");
String id = prefs.getString(AppConstants.ID, "");
Intent profactivity = new Intent(MainActivity.this, View.class);
profactivity.putExtra("Internet", false);
profactivity.putExtra("loginValue", loginValue);
profactivity.putExtra("id", id);
profactivity.putExtra("projectName", projectName);
profactivity.putExtra("stockPoint", stockPoint);
startActivity(profactivity);
**Toast.makeText(MainActivity.this, "Offline Login ", Toast.LENGTH_SHORT).show();
finish();
}
****对于上面的代码，这里是通过错误**
try {
final String loginValue = URLEncoder.encode(login.getText().toString(), "UTF-8");
final String passValue = URLEncoder.encode(password.getText().toString(), "UTF-8");
try {
new Thread(new Runnable() {
**//Thread to stop network calls on the UI thread**
public void run() {
//Request the HTML
ArrayList<String> list = null;
try {
String loginValue = URLEncoder.encode(login.getText().toString(), "UTF-8");
String passValue = URLEncoder.encode(password.getText().toString(), "UTF-8");
String ROOT_URL = getResources().getString(R.string.ROOT_URL) + "/api/v1/user/signIn?loginName=" + loginValue + "&password=" + passValue;
Log.i("httpget", "#####@@@@@@#####" + ROOT_URL);
HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet(ROOT_URL);
HttpResponse response = client.execute(request);
if (response.getStatusLine().getStatusCode() == 200) {
String server_response = EntityUtils.toString(response.getEntity());
myRespObject = new JSONObject(server_response);
//Do something with the response
//Toast.makeText(getBaseContext(),server_response,Toast.LENGTH_LONG).show();
statusRes = myRespObject.getString("status");
JSONObject respObject = myRespObject.getJSONObject("response");
id = respObject.getString("_id");
AppConstants._ID = id;
projectName = respObject.getString("projectName");
Actors actor = new Actors();
list = new ArrayList<>();
JSONArray jsonArray = respObject.getJSONArray("stockPoint");
Intent i = getIntent();
Serializable subject = i.getSerializableExtra("stockPoint");
if (jsonArray != null) {
int len = jsonArray.length();
for (int k = 0; k < len; k++)
list.add(jsonArray.get(k).toString());
}
actor.setStockPoint(list);
AppConstants.STOCK_POINT = stockPoint;
stockPoint = respObject.getString("stockPoint");
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
final ArrayList<String> finalList = list;
runOnUiThread(new Runnable() {
@Override
public void run() {
try {
statusRes = myRespObject.getString("status");
} catch (JSONException e) {
e.printStackTrace();
}
if (statusRes.equalsIgnoreCase("success")) {
SharedPreferences sharedpreferences = getSharedPreferences(AppConstants.MyPREFERENCES, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedpreferences.edit();
editor.putString(AppConstants.LOGIN_VALUE, loginValue);
editor.putString(AppConstants.PASS_KEY, passValue);
editor.putString("Internet", "true");
editor.putString(AppConstants.ID, id);
editor.putString(AppConstants.PROJECT_NAME, projectName);
editor.putString(String.valueOf(AppConstants.STOCK_POINT), String.valueOf(stockPoint));
editor.commit();
**//Here move to next screen or home screen**
Intent profactivity = new Intent(MainActivity.this, View.class); profactivity.putExtra("Internet", true); profactivity.putExtra("loginValue", loginValue); profactivity.putExtra("id", id);
profactivity.putExtra("projectName", projectName);
profactivity.putExtra("stockPoint", finalList);
startActivity(profactivity);
Toast.makeText(MainActivity.this, "Login Successfully", Toast.LENGTH_LONG).show();
finish();
} else if (statusRes.equalsIgnoreCase("failed")) {
if (!validate()) {
onLoginFailed();
return;
}
}
}
});
}
}).start();
//return data;
} catch (Exception e) {
Log.i("httpget", "#####@@@@@@#####Error1 -->" + e.getStackTrace());
**Toast.makeText(getBaseContext(), "ERROR : " + e.getMessage(), Toast.LENGTH_LONG).show();**
}
} catch (UnsupportedEncodingException ex) {
finish();
}
}
});
}
public boolean validate() {
boolean valid = true;
String email = login.getText().toString();
String passwor = password.getText().toString();
if (email.isEmpty() || email.length() < 2 || email.length() > 10) {
login.setError("enter valid username");
valid = false;
} else {
login.setError("Invalid username");
}
if (passwor.isEmpty() || passwor.length() < 2 || passwor.length() > 10) {
password.setError("enter valid password");
valid = false;
} else {
password.setError("Invalid password");
}
return valid;
}
public void onLoginFailed() {
**Toast.makeText(getBaseContext(), "Invalid login", Toast.LENGTH_LONG).show();**
}
}
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答案 0 :(得分：1)
您提到的错误表示您在以下行中有错误。
projectName = respObject.getString（＆＃34; projectName＆＃34;）;
＆＃34; responseObject＆＃34;是null，因此您获得NullPointerException。