I'm developing an Android app. I need to build a URI for my app to make an API request. Unless there's another way to put a variable in a URI, this is the easiest way I've found. I found that you need to use Uri.Builder, but I'm not quite sure how to. My url is:
http://lapi.transitchicago.com/api/1.0/ttarrivals.aspx?key=[redacted]&mapid=value
My scheme is http, authority is lapi.transitchicago.com, path is /api/1.0, path segment(s) is ttarrivals.aspx, and query string is key=[redacted]&mapid=value.
My code is below:
Intent intent = getIntent();
String value = intent.getExtras().getString("value");
Uri.Builder builder = new Uri.Builder();
builder.scheme("http")
.authority("www.lapi.transitchicago.com")
.appendPath("api")
.appendPath("1.0")
.appendPath("ttarrivals.aspx")
.appendQueryParameter("key", "[redacted]")
.appendQueryParameter("mapid", value);
I understand that I can do URI.add, but how do I integrate it into the Uri.Builder? Should I add everything like URI.add(scheme), URI.add(authority) and so on? Or is that not the way to do it? Also, is there any other easier way to add a variable to a URI/URL?
This question is related to
android
uri
uribuilder
Excellent answer from above turned into a simple utility method.
private Uri buildURI(String url, Map<String, String> params) {
// build url with parameters.
Uri.Builder builder = Uri.parse(url).buildUpon();
for (Map.Entry<String, String> entry : params.entrySet()) {
builder.appendQueryParameter(entry.getKey(), entry.getValue());
}
return builder.build();
}
There is another way of using Uri and we can achieve the same goal
http://api.example.org/data/2.5/forecast/daily?q=94043&mode=json&units=metric&cnt=7
To build the Uri you can use this:
final String FORECAST_BASE_URL =
"http://api.example.org/data/2.5/forecast/daily?";
final String QUERY_PARAM = "q";
final String FORMAT_PARAM = "mode";
final String UNITS_PARAM = "units";
final String DAYS_PARAM = "cnt";
You can declare all this the above way or even inside the Uri.parse() and appendQueryParameter()
Uri builtUri = Uri.parse(FORECAST_BASE_URL)
.buildUpon()
.appendQueryParameter(QUERY_PARAM, params[0])
.appendQueryParameter(FORMAT_PARAM, "json")
.appendQueryParameter(UNITS_PARAM, "metric")
.appendQueryParameter(DAYS_PARAM, Integer.toString(7))
.build();
At last
URL url = new URL(builtUri.toString());
for the example in the second Answer I used this technique for the same URL
http://api.example.org/data/2.5/forecast/daily?q=94043&mode=json&units=metric&cnt=7
Uri.Builder builder = new Uri.Builder();
builder.scheme("https")
.authority("api.openweathermap.org")
.appendPath("data")
.appendPath("2.5")
.appendPath("forecast")
.appendPath("daily")
.appendQueryParameter("q", params[0])
.appendQueryParameter("mode", "json")
.appendQueryParameter("units", "metric")
.appendQueryParameter("cnt", "7")
.appendQueryParameter("APPID", BuildConfig.OPEN_WEATHER_MAP_API_KEY);
then after finish building it get it as URL like this
URL url = new URL(builder.build().toString());
and open a connection
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
and if link is simple like location uri, for example
geo:0,0?q=29203
Uri geoLocation = Uri.parse("geo:0,0?").buildUpon()
.appendQueryParameter("q",29203).build();
here is a good way to explain it:
there are two forms of the URI
1 - Builder(ready to be modified, not ready to be used)
2 - Built(not ready to be modified, ready to be used )
You can create a builder by
Uri.Builder builder = new Uri.Builder();
this gonna return a Builder ready to be modified like this:-
builder.scheme("https");
builder.authority("api.github.com");
builder.appendPath("search");
builder.appendPath("repositories");
builder.appendQueryParameter(PARAMETER_QUERY,parameterValue);
but to use it you have to build it first
retrun builder.build();
or however you gonna use it. and then you have built that is already built for you, ready to use but cannot be modified.
Uri built = Uri.parse("your URI goes here");
this is ready to use but if you want to modify it you need to buildUpon()
Uri built = Uri.parse("Your URI goes here")
.buildUpon(); //now it's ready to be modified
.buildUpon()
.appendQueryParameter(QUERY_PARAMATER, parameterValue)
//any modification you want to make goes here
.build(); // you have to build it back cause you are storing it
// as Uri not Uri.builder
now every time you want to modify it you need to buildUpon() and in the end build().
so Uri.Builder is a Builder type that store a Builder in it. Uri is a Built type that store an already built URI in it.
new Uri.Builder(); rerurns a Builder. Uri.parse("your URI goes here") returns a Built.
and with build() you can change it from Builder to Built. buildUpon() you can change it from Built to Builder. Here is what you can do
Uri.Builder builder = Uri.parse("URL").buildUpon();
// here you created a builder, made an already built URI with Uri.parse
// and then change it to builder with buildUpon();
Uri built = builder.build();
//when you want to change your URI, change Builder
//when you want to use your URI, use Built
and also the opposite:-
Uri built = new Uri.Builder().build();
// here you created a reference to a built URI
// made a builder with new Uri.Builder() and then change it to a built with
// built();
Uri.Builder builder = built.buildUpon();
hope my answer helped :) <3
You can do that with lambda expressions;
private static final String BASE_URL = "http://api.example.org/data/2.5/forecast/daily";
private String getBaseUrl(Map<String, String> params) {
final Uri.Builder builder = Uri.parse(BASE_URL).buildUpon();
params.entrySet().forEach(entry -> builder.appendQueryParameter(entry.getKey(), entry.getValue()));
return builder.build().toString();
}
and you can create params like that;
Map<String, String> params = new HashMap<String, String>();
params.put("zip", "94043,us");
params.put("units", "metric");
Btw. If you will face any issue like “lambda expressions not supported at this language level”, please check this URL;
Best answer: https://stackoverflow.com/a/19168199/413127
Example for
http://api.example.org/data/2.5/forecast/daily?q=94043&mode=json&units=metric&cnt=7
Now with Kotlin
val myUrl = Uri.Builder().apply {
scheme("https")
authority("www.myawesomesite.com")
appendPath("turtles")
appendPath("types")
appendQueryParameter("type", "1")
appendQueryParameter("sort", "relevance")
fragment("section-name")
build()
}.toString()
Using appendEncodePath() could save you multiple lines than appendPath(), the following code snippet builds up this url: http://api.openweathermap.org/data/2.5/forecast/daily?zip=94043
Uri.Builder urlBuilder = new Uri.Builder();
urlBuilder.scheme("http");
urlBuilder.authority("api.openweathermap.org");
urlBuilder.appendEncodedPath("data/2.5/forecast/daily");
urlBuilder.appendQueryParameter("zip", "94043,us");
URL url = new URL(urlBuilder.build().toString());
Source: Stackoverflow.com