我正在构建一个android应用程序，并且我在帮助程序类获取应用程序上下文时遇到了一些麻烦。 我有两个调用我的帮助器类的函数的活动，它们都传递了应用程序上下文但只有一个有效，另一个给了我一个NPE。
活动是相关的，HomeActivity转到ArCondicionadoActivity，带有一些额外功能，在函数调用后几行。
这是助手类代码：
public class AccessToken {
private SharedPreferences sharedPreferences;
private OkHttpClient client = new OkHttpClient();
private MediaType JSON = MediaType.parse("application/json; charset=utf-8");
private JSONObject jsonBodyParams = new JSONObject();
private JSONObject jsonBodyParamsRefresh = new JSONObject();
private Boolean loggedIn = false;
private String token;
private String refreshToken;
private String userID;
private FileInputStream FJWT;
private FileInputStream FID;
private FileInputStream FJWR;
private FileOutputStream FOST;
public Boolean validaLogin(Context context) throws IOException {
FJWT = context.openFileInput("JWToken");
InternalFileReader IFT = new InternalFileReader();
token = IFT.readFile(FJWT);
Log.i("tokenlidoT", token);
FJWR = context.openFileInput("JWRefreshToken");
InternalFileReader IFR = new InternalFileReader();
refreshToken = IFR.readFile(FJWR);
Log.i("tokenlidoR", refreshToken);
FID = context.openFileInput("UID");
InternalFileReader IFU = new InternalFileReader();
userID = IFU.readFile(FID);
Log.i("UIDLido", userID);
OkHttpClient.Builder builder = new OkHttpClient.Builder();
builder.connectTimeout(30, TimeUnit.SECONDS);
builder.readTimeout(30, TimeUnit.SECONDS);
builder.writeTimeout(30, TimeUnit.SECONDS);
client = builder.build();
if (token!=null){
try {
jsonBodyParams.put("token", token);
Log.i("tokenLidoInternal", token);
} catch (JSONException e) {
e.printStackTrace();
}
RequestBody loginBody = RequestBody.create(JSON, jsonBodyParams.toString());
Request request = new Request.Builder()
.url(context.getResources().getString(R.string.verify_url))
.header("Content-Type", "application/json")
.post(loginBody)
.build();
Log.i("request", String.valueOf(request.headers()));
Log.i("request", String.valueOf(jsonBodyParams.toString()));
Log.i("request", String.valueOf(request));
Response response = null;
try {
response = client.newCall(request).execute();
} catch (IOException e) {
Log.i("INITIRESPONSE", "FAIL");
e.printStackTrace();
}
Log.i("INITRESPONSE", String.valueOf(response));
Log.i("INITRESPONSE", String.valueOf(response.isSuccessful()));
if (!response.isSuccessful()) {
if (refreshToken!=null){
try {
jsonBodyParamsRefresh.put("refresh", refreshToken);
Log.i("refreshTokenLido", refreshToken);
} catch (JSONException e) {
e.printStackTrace();
}
RequestBody refreshBody = RequestBody.create(JSON, jsonBodyParamsRefresh.toString());
Request requestRefresh = new Request.Builder()
.url(context.getResources().getString(R.string.verify_url_refresh_token))
.header("Content-Type", "application/json")
.post(refreshBody)
.build();
Log.i("requestRefresh", String.valueOf(requestRefresh.headers()));
Log.i("requestRefresh", String.valueOf(jsonBodyParamsRefresh.toString()));
Log.i("requestRefresh", String.valueOf(requestRefresh));
Response responseRefresh = null;
try {
responseRefresh = client.newCall(requestRefresh).execute();
} catch (IOException e) {
Log.i("INITIRESPONSEREFRESH", "FAIL");
e.printStackTrace();
}
Log.i("INITIRESPONSEREFRESH", String.valueOf(responseRefresh));
Log.i("INITIRESPONSEREFRESH", String.valueOf(responseRefresh.isSuccessful()));
if (!responseRefresh.isSuccessful()){
loggedIn = false;
Log.i("RESULT", "response not successfull");
throw new IOException("Unexpected code " + responseRefresh);
}else {
Log.i("RESULTREFRESH", "refresh response successfull");
JSONObject responseBodyJson = null;
try {
responseBodyJson = new JSONObject(responseRefresh.body().string());
} catch (JSONException | IOException e) {
e.printStackTrace();
}
try {
assert responseBodyJson != null;
FOST = context.openFileOutput("JWToken", Context.MODE_PRIVATE);
String stringToken = responseBodyJson.getString("accessToken");
FOST.write(stringToken.getBytes());
FOST.close();
} catch (IOException e) {
Log.i("IOE", "refreshAccess");
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
loggedIn = true;
}
responseRefresh.close();
}else {
Log.i("RESULT", "refresh token non-existent");
loggedIn = false;
}
} else {
Log.i("RESULT", "response successfull");
loggedIn = true;
}
response.close();
} else {
loggedIn = false;
Log.i("RESULT", "token non-existent");
}
return loggedIn;
}
public String validaLoginTokenReturn(Context context) throws IOException {
FJWT = context.openFileInput("JWToken");
InternalFileReader IFT = new InternalFileReader();
token = IFT.readFile(FJWT);
Log.i("tokenlidoT", token);
FJWR = context.openFileInput("JWRefreshToken");
InternalFileReader IFR = new InternalFileReader();
refreshToken = IFR.readFile(FJWR);
Log.i("tokenlidoR", refreshToken);
FID = context.openFileInput("UID");
InternalFileReader IFU = new InternalFileReader();
userID = IFU.readFile(FID);
Log.i("UIDLido", userID);
OkHttpClient.Builder builder = new OkHttpClient.Builder();
builder.connectTimeout(30, TimeUnit.SECONDS);
builder.readTimeout(30, TimeUnit.SECONDS);
builder.writeTimeout(30, TimeUnit.SECONDS);
client = builder.build();
if (token!=null){
try {
jsonBodyParams.put("token", token);
Log.i("tokenLidoInternal", token);
} catch (JSONException e) {
e.printStackTrace();
}
RequestBody loginBody = RequestBody.create(JSON, jsonBodyParams.toString());
Request request = new Request.Builder()
.url(context.getResources().getString(R.string.verify_url))
.header("Content-Type", "application/json")
.post(loginBody)
.build();
Log.i("request", String.valueOf(request.headers()));
Log.i("request", String.valueOf(jsonBodyParams.toString()));
Log.i("request", String.valueOf(request));
Response response = null;
try {
response = client.newCall(request).execute();
} catch (IOException e) {
Log.i("INITIRESPONSE", "FAIL");
e.printStackTrace();
}
Log.i("INITRESPONSE", String.valueOf(response));
Log.i("INITRESPONSE", String.valueOf(response.isSuccessful()));
if (!response.isSuccessful()) {
if (refreshToken!=null){
try {
jsonBodyParamsRefresh.put("refresh", refreshToken);
Log.i("refreshTokenLido", refreshToken);
} catch (JSONException e) {
e.printStackTrace();
}
RequestBody refreshBody = RequestBody.create(JSON, jsonBodyParamsRefresh.toString());
Request requestRefresh = new Request.Builder()
.url(context.getResources().getString(R.string.verify_url_refresh_token))
.header("Content-Type", "application/json")
.post(refreshBody)
.build();
Log.i("requestRefresh", String.valueOf(requestRefresh.headers()));
Log.i("requestRefresh", String.valueOf(jsonBodyParamsRefresh.toString()));
Log.i("requestRefresh", String.valueOf(requestRefresh));
Response responseRefresh = null;
try {
responseRefresh = client.newCall(requestRefresh).execute();
} catch (IOException e) {
Log.i("INITIRESPONSEREFRESH", "FAIL");
e.printStackTrace();
}
Log.i("INITIRESPONSEREFRESH", String.valueOf(responseRefresh));
Log.i("INITIRESPONSEREFRESH", String.valueOf(responseRefresh.isSuccessful()));
if (!responseRefresh.isSuccessful()){
Log.i("RESULT", "response not successfull");
throw new IOException("Unexpected code " + responseRefresh);
}else {
Log.i("RESULTREFRESH", "refresh response successfull");
JSONObject responseBodyJson = null;
try {
responseBodyJson = new JSONObject(responseRefresh.body().string());
} catch (JSONException | IOException e) {
e.printStackTrace();
}
try {
assert responseBodyJson != null;
FOST = context.openFileOutput("JWToken", Context.MODE_PRIVATE);
String stringToken = responseBodyJson.getString("accessToken");
token = stringToken;
FOST.write(stringToken.getBytes());
FOST.close();
} catch (IOException e) {
Log.i("IOE", "refreshAccess");
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
}
responseRefresh.close();
}else {
Log.i("RESULT", "refresh token non-existent");
}
} else {
Log.i("RESULT", "response successfull");
}
response.close();
} else {
Log.i("RESULT", "token non-existent");
}
return token;
}
}
以下是调用（仅实际调用点之前的活动部分），首先是有效的调用（HomeActivity）：
String tokenLido = "randomTokenForTesting";
airConditioningButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new HomeActivity.getParamAirConditioning().execute(tokenLido);
}
});
private class getParamAirConditioning extends AsyncTask<String, Void, Response> {
@Override
protected void onPreExecute() {
loadingDialog = ProgressDialog.show(HomeActivity.this,
"Please wait...", "Getting data from server");
loadingDialog.setCancelable(false);
}
protected Response doInBackground(String... params) {
String token = params[0];
MediaType JSON = MediaType.parse("application/json; charset=utf-8");
OkHttpClient client = new OkHttpClient();
JSONObject jsonBodyParams = new JSONObject();
try {
jsonBodyParams.put("acID", "1");
} catch (JSONException e) {
e.printStackTrace();
}
try {
token = accessToken.validaLoginTokenReturn(HomeActivity.this);
} catch (IOException e) {
e.printStackTrace();
}
现在是那个没有（ArCondicionadoActivity）的人：
String tokenLido = "randomTokenForTesting";
String temperatura= "randomTemperatureForTesting";
String fanSpeed= "randomFanSpeedForTesting";
String humidity= "randomHumidityForTesting";
confirma.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new ArCondicionadoActivity.acUpdateServer().execute(tokenLido, temperatura, fanSpeed, humidity);
}
});
private class acUpdateServer extends AsyncTask<String, Void, Response> {
@Override
protected void onPreExecute() {
loadingDialog = ProgressDialog.show(ArCondicionadoActivity.this,
"Please wait...", "Updating data to server");
loadingDialog.setCancelable(false);
}
protected Response doInBackground(String... params) {
String token = params[0];
String temperaturaUpdate = params[1];
String acFanSpeedUpdate = params[2];
String humidityUpdate = params[3];
MediaType JSON = MediaType.parse("application/json; charset=utf-8");
OkHttpClient client = new OkHttpClient();
JSONObject jsonBodyParams = new JSONObject();
try {
jsonBodyParams.put("acID", "1");
jsonBodyParams.put("acIsTurnedOn", "1");
jsonBodyParams.put("acTemp", temperaturaUpdate);
jsonBodyParams.put("acFanSpeed", acFanSpeedUpdate);
jsonBodyParams.put("acHumidity", humidityUpdate);
} catch (JSONException e) {
e.printStackTrace();
}
try {
token = accessToken.validaLoginTokenReturn(ArCondicionadoActivity.this);
} catch (IOException e) {
e.printStackTrace();
}
我的堆栈如下：
08-29 21:08:06.631 10098-10529/com.example.giovanni.tcc E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #4
Process: com.example.giovanni.tcc, PID: 10098
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:318)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:761)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.example.giovanni.tcc.Security.AccessToken.validaLoginTokenReturn(android.content.Context)' on a null object reference
at com.example.giovanni.tcc.ArCondicionadoActivity$acUpdateServer.doInBackground(ArCondicionadoActivity.java:313)
at com.example.giovanni.tcc.ArCondicionadoActivity$acUpdateServer.doInBackground(ArCondicionadoActivity.java:277)
at android.os.AsyncTask$2.call(AsyncTask.java:304)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:243)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:761)
我很欣赏在第二部分我在那里做错的任何见解。
对于一些葡萄牙语的名字感到抱歉，希望它没有太多的方式= P