Output an object to the Logcat console - android

I would like to take a look at an object, similar to a print_r(an_object) in php, or a console.log(an_object) in javascript (in browser), but for Android.
I tried this
public void a_method( SomeClass the_arg )
{
Log.d( "an_id" , the_arg );
}
This generates an error message:
Error:(23, 10) error: no suitable method found for d(String,View)
method Log.d(String,String,Throwable) is not applicable
(actual and formal argument lists differ in length)
method Log.d(String,String) is not applicable
(actual argument View cannot be converted to String by method invocation conversion)


You cannot print an object to the console in Java as you would in javascript.
You have three solutions.
1) Use debugger. Place a breakpoint and debug in android studio. Then you can inspect the full object in scope.
2) Serialize your object (for example to JSON) and print the result to console.
3) Override toString method of your object to give you all the information you want and call Log.d("myTag", yourObj.toString())
I highly recommend first method. I used to avoid Debugger but learning how to use the debugger was the best thing I did. It increases your efficiency and makes debugging super easy


Convert object to JSON. You can use Gson.
val gson = Gson()
val json = gson.toJson(yourObject)
Log.e(TAG, json)
Or
Log.e(TAG, Gson().toJson(yourObject))


The second argument must be a String.
Log.d("an_id", String.valueOf(the_arg));
Your error says you can't log a View class
no suitable method found for d(String,View)
Don't be surprised when you see some nonsense in the console when you print that View object through using String.valueOf


It's a bit easy to output the data object in the logcat.
The correct way is to override the toString() inside the object.
It can be generated by the Android Studio itself by following this simple steps:
1- Open the DataClass
2- Press Alt+Insert OR right click and click on Generate...
3- In Generate window select toString()
4- Select all the variables in the next window and click OK
5- toString() method would override in your data class returning the String template of your data model.
Cheers!


just wrote one generic method, which makes it possible trough reflection:
#Override
public String toString() {
StringBuilder sb = new StringBuilder();
for (Field field : this.getClass().getDeclaredFields()) {
String item;
if(! field.getType().getSimpleName().equals("ArrayList")) {
try {
Object value = field.get(this);
item = String.format("%s %s %s: %s%n", Modifier.toString(field.getModifiers()), field.getType().getSimpleName(), field.getName(), String.valueOf(value));
sb.append(item);
} catch (IllegalAccessException e) {
e.printStackTrace();
}
} else {
item = String.format("%s %s %s: ArrayList<>%n", Modifier.toString(field.getModifiers()), field.getType().getSimpleName(), field.getName());
sb.append(item);
}
}
return sb.toString();
}


You can try using Gson class as shown below :
public void yourMethod(SomeClass theObject) {
Gson gson = new Gson();
Log.d( "sample" , gson.toJson(theObject));
}
Here is its Gradle repository
implementation 'com.google.code.gson:gson:2.8.6'

Related

retrofit2 errorbody.content is not accessible

I am new in retrofit2 world, currently I have a problem on getting errorbody from onNext.
Here is my sample code :
public void onNext(Response<LoginResponse> value) {
ResponseBody responseBody = value.errorBody();
String sam = responseBody.toString();
}
My issue is, I cant get the errorbody().content. It is like it is not accessible.

You can try:
String errorBody = value.errorBody().string;
or
String errorBody = value.errorBody().toString();

Retrofit's error bodys are of type OkHttp3 ResponseBody. This class is abstract and its implementations define different ways the content is represented internally.
There are different ways you can get the content. You can get it in bytes, as a string, or even get an InputStream for it - check them out here.
I suppose an easy way is to use string():
value.errorBody().string();
Note that these methods usually read the response from a buffer, which means that if I recall correctly, calling again string() would not give you the content of the response again. In particular, string() also reads the entire body into memory, which may cause an out of memory exception.
After you have the content, if you want it as an object from your data model, you'll have to deserialize it manually. There are numerous ways to do this and it's easy to find on the web, but for sake of completeness, here's a way to do it with gson:
String error = value.errorBody().string();
MyPojo pojo = new Gson().fromJson(error, MyPojo.class);
(here MyPojo would be your error class representing the error)

You can't get errorBody without http-error code.
Use smt like this:
if (!value.isSuccessful && value.errorBody() != null) {
val errorBodyText = value.errorBody()?.string()?:""
val errorResponse = Gson().fromJson<ErrorObject>(errorBodyText, ErrorObject::class.java)
}

android Expected BEGIN_OBJECT but was STRING at line 1 column 1 [duplicate]

I have this method:
public static Object parseStringToObject(String json) {
String Object = json;
Gson gson = new Gson();
Object objects = gson.fromJson(object, Object.class);
parseConfigFromObjectToString(object);
return objects;
}
And I want to parse a JSON with:
public static void addObject(String IP, Object addObject) {
try {
String json = sendPostRequest("http://" + IP + ":3000/config/add_Object", ConfigJSONParser.parseConfigFromObjectToString(addObject));
addObject = ConfigJSONParser.parseStringToObject(json);
} catch (Exception ex) {
ex.printStackTrace();
}
}
But I get an error message:
com.google.gson.JsonSyntaxException: java.lang.IllegalStateException:
Expected BEGIN_OBJECT but was STRING at line 1 column 1

Even without seeing your JSON string you can tell from the error message that it is not the correct structure to be parsed into an instance of your class.
Gson is expecting your JSON string to begin with an object opening brace. e.g.
{
But the string you have passed to it starts with an open quotes
"

Invalid JSON from the server should always be an expected use case. A million things can go wrong during transmission. Gson is a bit tricky, because its error output will give you one problem, and the actual exception you catch will be of a different type.
With all that in mind, the proper fix on the client side is
try
{
gson.fromJSON(ad, Ad.class);
//...
}
catch (IllegalStateException | JsonSyntaxException exception)
{
//...
If you want to know why the JSON you received from the server is wrong, you can look inside your catch block at the exception. But even if it is your problem, it's not the client's responsibility to fix JSON it is receiving from the internet.
Either way, it is the client's responsibility to decide what to do when it gets bad JSON. Two possibilities are rejecting the JSON and doing nothing, and trying again.
If you are going to try again, I highly recommend setting a flag inside the try / catch block and then responding to that flag outside the try / catch block. Nested try / catch is likely how Gson got us into this mess with our stack trace and exceptions not matching up.
In other words, even though I'll admit it doesn't look very elegant, I would recommend
boolean failed = false;
try
{
gson.fromJSON(ad, Ad.class);
//...
}
catch (IllegalStateException | JsonSyntaxException exception)
{
failed = true;
//...
}
if (failed)
{
//...

I had a similar problem recently and found an interesting solution. Basically I needed to deserialize following nested JSON String into my POJO:
"{\"restaurant\":{\"id\":\"abc-012\",\"name\":\"good restaurant\",\"foodType\":\"American\",\"phoneNumber\":\"123-456-7890\",\"currency\":\"USD\",\"website\":\"website.com\",\"location\":{\"address\":{\"street\":\" Good Street\",\"city\":\"Good City\",\"state\":\"CA\",\"country\":\"USA\",\"postalCode\":\"12345\"},\"coordinates\":{\"latitude\":\"00.7904692\",\"longitude\":\"-000.4047208\"}},\"restaurantUser\":{\"firstName\":\"test\",\"lastName\":\"test\",\"email\":\"test#test.com\",\"title\":\"server\",\"phone\":\"0000000000\"}}}"
I ended up using regex to remove the open quotes from beginning and the end of JSON and then used apache.commons unescapeJava() method to unescape it. Basically passed the unclean JSON into following method to get back a cleansed one:
private String removeQuotesAndUnescape(String uncleanJson) {
String noQuotes = uncleanJson.replaceAll("^\"|\"$", "");
return StringEscapeUtils.unescapeJava(noQuotes);
}
then used Google GSON to parse it into my own Object:
MyObject myObject = new.Gson().fromJson(this.removeQuotesAndUnescape(uncleanJson));

In Retrofit2, When you want to send your parameters in raw you must use Scalars.
first add this in your gradle:
compile 'com.squareup.retrofit2:retrofit:2.3.0'
compile 'com.squareup.retrofit2:converter-gson:2.3.0'
compile 'com.squareup.retrofit2:converter-scalars:2.3.0'
public interface ApiInterface {
String URL_BASE = "http://10.157.102.22/rest/";
#Headers("Content-Type: application/json")
#POST("login")
Call<User> getUser(#Body String body);
}
my SampleActivity :
public class SampleActivity extends AppCompatActivity implements Callback<User> {
#Override
protected void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_sample);
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(ApiInterface.URL_BASE)
.addConverterFactory(ScalarsConverterFactory.create())
.addConverterFactory(GsonConverterFactory.create())
.build();
ApiInterface apiInterface = retrofit.create(ApiInterface.class);
// prepare call in Retrofit 2.0
try {
JSONObject paramObject = new JSONObject();
paramObject.put("email", "sample#gmail.com");
paramObject.put("pass", "4384984938943");
Call<User> userCall = apiInterface.getUser(paramObject.toString());
userCall.enqueue(this);
} catch (JSONException e) {
e.printStackTrace();
}
}
#Override
public void onResponse(Call<User> call, Response<User> response) {
}
#Override
public void onFailure(Call<User> call, Throwable t) {
}
}
Reference: [How to POST raw whole JSON in the body of a Retrofit request?

I have come to share an solution. The error happened to me after forcing the notbook to hang up. possible solution clean preject.

Maybe your JSON Object is right,but the response that you received is not your valid data.Just like when you connect the invalid WiFi,you may received a strange response < html>.....< /html> that GSON can not parse.
you may need to do some try..catch.. for this strange response to avoid crash.

Make sure you have DESERIALIZED objects like DATE/DATETIME etc. If you are directly sending JSON without deserializing it then it can cause this problem.

In my situation, I have a "model", consist of several String parameters, with the exception of one: it is byte array byte[].
Some code snippet:
String response = args[0].toString();
Gson gson = new Gson();
BaseModel responseModel = gson.fromJson(response, BaseModel.class);
The last line above is when the
java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING at line 1 column
is triggered. Searching through the SO, I realised I need to have some form of Adapter to convert my BaseModel to and fro a JsonObject. Having mixed of String and byte[] in a model does complicate thing. Apparently, Gson don't really like the situation.
I end up making an Adapter to ensure byte[] is converted to Base64 format. Here is my Adapter class:
public class ByteArrayToBase64Adapter implements JsonSerializer<byte[]>, JsonDeserializer<byte[]> {
#Override
public byte[] deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
return Base64.decode(json.getAsString(), Base64.NO_WRAP);
}
#Override
public JsonElement serialize(byte[] src, Type typeOfSrc, JsonSerializationContext context) {
return new JsonPrimitive(Base64.encodeToString(src, Base64.NO_WRAP));
}
}
To convert JSONObject to model, I used the following:
Gson customGson = new GsonBuilder().registerTypeHierarchyAdapter(byte[].class, new ByteArrayToBase64Adapter()).create();
BaseModel responseModel = customGson.fromJson(response, BaseModel.class);
Similarly, to convert the model to JSONObject, I used the following:
Gson customGson = new GsonBuilder().registerTypeHierarchyAdapter(byte[].class, new ByteArrayToBase64Adapter()).create();
String responseJSon = customGson.toJson(response);
What the code is doing is basically to push the intended class/object (in this case, byte[] class) through the Adapter whenever it is encountered during the convertion to/fro JSONObject.

Don't use jsonObject.toString on a JSON object.

In my case, I am Returning JSON Object as
{"data":"","message":"Attendance Saved
Successfully..!!!","status":"success"}
Resolved by changing it as
{"data":{},"message":"Attendance Saved
Successfully..!!!","status":"success"}
Here data is a sub JsonObject and it should starts from { not ""

Don't forget to convert your object into Json first using Gson()
val fromUserJson = Gson().toJson(notificationRequest.fromUser)
Then you can easily convert it back into an object using this awesome library
val fromUser = Gson().fromJson(fromUserJson, User::class.java)

if your json format and variables are okay then check your database queries...even if data is saved in db correctly the actual problem might be in there...recheck your queries and try again.. Hope it helps

I had a case where I read from a handwritten json file. The json is perfect. However, this error occurred. So I write from a java object to json file, then read from that json file. things are fine. I could not see any difference between the handwritten json and the one from java object. Tried beyondCompare it sees no difference.
I finally noticed the two file sizes are slightly different, and I used winHex tool and detected extra stuff.
So the solution for my situation is, make copy of the good json file, paste content into it and use.

In my case, my custom http-client didn't support the gzip encoding. I was sending the "Accept-Encoding: gzip" header, and so the response was sent back as a gzip string and couldn't be decoded.
The solution was to not send that header.

I was making a POST request with some parameters using Retrofit in Android
WHAT I FACED:
The error I was getting in Android Studio logcat:
java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING
at line 2 column 1 path $
[but it was working fine with VOLLY library]
when I googled it...
you know[ Obviously json is expecting a OBJECT but...]
BUT when I changed my service to return a simple string [ like print_r("don't lose hope") ] or
Noting at all
It was getting printed fine in Postman
but in Android studio logcat, it was still SAME ERROR [
java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING
at line 2 column 1 path $
]
Hold up now, I am sending a simple message or not sending anything in response and still studio is
telling me "...Expected BEGIN_OBJECT but was STRING..."
SOMETHING IS WRONG
On 4th day:
I finally stopped for looking "QUICK SOLUTIONS" and REALLY READ some stack overflow questions
and articles carefully.
WHAT I GOT:
Logging interceptor
It will show you whatever data comes from your server[even eco messages] which are not shown in
Andorid studios logcat,
that way you can FIND THE PROBLEM.
What I found is I was sending data with #Body like-
#Headers("Content-Type: application/json")
#POST("CreateNewPost")
Call<Resp> createNewPost(#Body ParaModel paraModel);
but no parameter was reaching to server, everything was null [I found using Logging interceptor]
then I simply searched an article "how to make POST request using Retrofit"
here's one
SOLUTION:
from here I changed my method to:
#POST("CreateNewPost")
#FormUrlEncoded
Call<Resp> createNewPost(
#Field("user_id") Integer user_id,
#Field("user_name") String user_name,
#Field("description") String description,
#Field("tags") String tags);
and everything was fine.
CONCLUSION:
I don't understand why Retrofit gave this error
java.lang.IllegalStateException: Expected BEGIN_OBJECT but was STRING
at line 2 column 1 path $
it doesn't make any sense at all.
So ALWAYS DEBUG in detail then find WHERE THINGS ARE LEAKING and then FIX.

This error solved for by replacing .toString method to .string on the response
toString => string (add in try{...code..}catche(IOException e))
below code is working for me
try {
MainModelResponse model;
Gson gson = new GsonBuilder().create();
if (response.code() == ConstantValues.SUCCESS_OK) {
model = gson.fromJson(response.body().string(), MainModelResponse.class);
} else {
model = gson.fromJson(response.errorBody().string(), MainModelResponse.class);
}
moduleData.postValue(model);
}catch (IllegalStateException | JsonSyntaxException | IOException exception){
exception.printStackTrace();
}
}

use a string begin & end with {}.
such as
final String jsStr = "{\"metric\":\"opentsdb_metric\",\"tags\":{\"testtag\":\"sunbotest\"},\"aggregateTags\":[],\"dps\":{\"1483399261\":18}}";
DataPoint dataPoint = new Gson().fromJson(jsStr, DataPoint.class);
this works for me.

In my case the object was all fine even the Json Validator was giving it a valid resposne but I was using Interface like this
#POST(NetworkConstants.REGISTER_USER)
Call<UserResponse> registerUser(
#Query("name") String name,
#Query("email") String email,
#Query("password") String password,
#Query("created_date") Long creationDate
);
Then I changed the code to
#FormUrlEncoded
#POST(NetworkConstants.REGISTER_USER)
Call<UserResponse> registerUser(
#Field("name") String name,
#Field("email") String email,
#Field("password") String password,
#Field("created_date") Long creationDate
);
And everything was resolved.

my problem not related to my codes
after copy some files from an other project got this issue
in the stack pointed to Gson library
in android studio 4.2.1 this problem not solved when I try file-> invalidate and restart
and
after restart in first time build got same error but in second build this problem solved
I don't understand why this happened

I was using an old version of retrofit library. So what I had to do was to change my code from this after upgrading it to com.squareup.retrofit2:retrofit:2.9.0:
#POST(AppConstants.UPLOAD_TRANSACTION_DETAIL)
fun postPremiumAppTransactionDetail(
#Query("name") planName:String,
#Query("amount") amount:String,
#Query("user_id") userId: String,
#Query("sub_id") planId: String,
#Query("folder") description:String,
#Query("payment_type") paymentType:String):
Call<TransactionResponseModel>
To this:
#FormUrlEncoded
#POST(AppConstants.UPLOAD_TRANSACTION_DETAIL)
fun postPremiumAppTransactionDetail(
#Field("name") planName:String,
#Field("amount") amount:String,
#Field("user_id") userId: String,
#Field("sub_id") planId: String,
#Field("folder") description:String,
#Field("payment_type") paymentType:String):
Call<TransactionResponseModel>

For me it turned out that I was trying to deserialize to an object that used java.time.ZonedDateTime for one of the properties. It worked as soon as I changed it to a java.util.Date instead.

Retrofit Response , custom response fields

I am using Retrofit and GSON to make an API call,
the problem that I have some fields in my models that doesn't exist in the response and I need to set them manually, example:
I have in my model: fieldOne, fieldTow, fieldThree
so fieldOne, fieldTow come in the response,
but fieldThree I need to set it manually and it's depends to fieldOne, fieldTow
ex
if (fieldOne!= null && fieldTow!= null) {
fieldThree = true
}
I need to do that at the moment when create that object and parse it
can you give me some help thanks

You can check key exist or not using jsonObject.has like following way,
JSONObject jsonObject=new JSONObject();
if(jsonObject.has("reviewer_details")){
//do process with data
}
Hope this will help

I think there two ways to achive it.
1(hardest). Write own JSON typed adapter implementation and do something like #Saneesh says.
See tutorial
2(easiest). Do this logic in getter method for your POJO object.
public boolean isFieldThree() {
if (fieldthree != null) return fieldThree;
//otherwise
return fieldOne!= null && fieldTow!= null;
}

Android: Handle different type of value with GSON

In my app, I get and parse a JSON stream from a wordpress (RESP API v2) website.
I use, OKHTTP, RETROFIT with GSON converter to read and parse the stream into my objects.
Usually, my GSON converter expect an object but, because of a recent update, the website gives me a boolean (false). The value isn't set yet.
This is my question: "Can I handle different type of values for the same variable name with GSON Serialize and how?"
Thank you!
This is my object:
public static class StageProfileImage {
//////////////////////////////////////////////////
// Variables
//////////////////////////////////////////////////
#SerializedName("url")
private String stageProfileImageUri;
//////////////////////////////////////////////////
//////////////////////////////////////////////////
// Setters & Getters
//////////////////////////////////////////////////
public String getStageProfileImageUri() {
return stageProfileImageUri;
}
public void setStageProfilUri(String stageProfileImageUri) {
this.stageProfileImageUri = stageProfileImageUri;
}
/////////////////////////////////////////////
}
Important: I can't modify the stream.

try #SerializedName(value = "url", alternate = {"altkey1", "altkey2"})
Edit: Changed to a more generic example.

Thanks but it isn't my problem. In fact, GSON can't convert the stream from the website because instead of this:
"stage_profile_image" : {
...
}
My stream give me that:
"stage_profile_image" : false
In the first one, I get an object but in the second one I get a boolean which is not the type of value it expects and GSON is unable to do the convertion.

How can I pass data to libcore on Android?

I was modifying the libcore on Andorid for debugging purpose.
It took a lot of time to build even for a variable change.
Is it possible to pass the data to libcore of android?
(so I can change the data in the running time).
I tried System.getProperty() but the data could not cross process.
I also tried SystemProperties.get() but it seems it can not be used in libcore (it could not find the package and symbol).
Does anyone know how to pass data to the libcore on Android?

Thanks Nativ.
JNI is doable but a little complicated for me.
Finally, I used a simple, easy but stupid way to do that.
I created a file and saved my parameter in this file, and get the data from libcore.
It is a stupid way but worked for me for debugging.
Now I don't need to rebuild libcore and It saved much for me.

You can use reflection on class android.os.SystemProperties to get System Properties at runtime.
Code example:
public static String getSystemProperty(String key) {
String value = "";
try {
Class clazz = Class.forName("android.os.SystemProperties");
if (clazz != null) {
Object object = clazz.newInstance();
value = (String) (clazz.getMethod("get", String.class).invoke(object, key));
} else {
System.err.println(TAG + ", getSystemProperty: Class is null.");
}
} catch (Exception e) {
e.printStackTrace();
}
return value;
}

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