filters: represent POST as json becausr booleans cannot be represented in urlencoded as Pleroma thinks

app/src/main/java/com/keylesspalace/tusky/FiltersActivity.kt

@@ -39,7 +39,7 @@ class FiltersActivity: BaseActivity() {
     }
 
     private fun updateFilter(filter: Filter, itemIndex: Int) {
-        api.updateFilter(filter.id, filter.phrase, filter.context, filter.irreversible, filter.wholeWord, filter.expiresAt)
+        api.updateFilter(filter.id, MastodonApi.PostFilter(filter.phrase, filter.context, filter.irreversible, filter.wholeWord, filter.expiresAt))
             .enqueue(object: Callback<Filter>{
                 override fun onFailure(call: Call<Filter>, t: Throwable) {
                     Toast.makeText(this@FiltersActivity, "Error updating filter '${filter.phrase}'", Toast.LENGTH_SHORT).show()
@@ -83,7 +83,8 @@ class FiltersActivity: BaseActivity() {
     }
 
     private fun createFilter(phrase: String, wholeWord: Boolean) {
-        api.createFilter(phrase, listOf(context), false, wholeWord, "").enqueue(object: Callback<Filter> {
+        api.createFilter(MastodonApi.PostFilter(phrase, listOf(context), false, wholeWord, ""))
+           .enqueue(object: Callback<Filter> {
             override fun onResponse(call: Call<Filter>, response: Response<Filter>) {
                 val filterResponse = response.body()
                 if(response.isSuccessful && filterResponse != null) {

app/src/main/java/com/keylesspalace/tusky/network/MastodonApi.kt

@@ -479,25 +479,21 @@ interface MastodonApi {
             @Query("limit") limit: Int
     ): Call<List<Conversation>>
 
-    @FormUrlEncoded
+    data class PostFilter(
+        val phrase: String,
+        val context: List<String>,
+        val irreversible: Boolean?,
+        val whole_word: Boolean?,
+        val expires_in: String?
+    );
+
     @POST("api/v1/filters")
-    fun createFilter(
-            @Field("phrase") phrase: String,
-            @Field("context[]") context: List<String>,
-            @Field("irreversible") irreversible: Boolean?,
-            @Field("whole_word") wholeWord: Boolean?,
-            @Field("expires_in") expiresIn: String?
-    ): Call<Filter>
+    fun createFilter(@Body body: PostFilter): Call<Filter>
 
-    @FormUrlEncoded
     @PUT("api/v1/filters/{id}")
     fun updateFilter(
             @Path("id") id: String,
-            @Field("phrase") phrase: String,
-            @Field("context[]") context: List<String>,
-            @Field("irreversible") irreversible: Boolean?,
-            @Field("whole_word") wholeWord: Boolean?,
-            @Field("expires_in") expiresIn: String?
+            @Body body: PostFilter
     ): Call<Filter>
 
     @DELETE("api/v1/filters/{id}")