Manual Search Activity Code:
package com.example.theweathertoday
import android.os.AsyncTask
import android.os.Bundle
import android.view.View
import android.widget.Button
import android.widget.EditText
import android.widget.ProgressBar
import android.widget.RelativeLayout
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
import org.json.JSONObject
import java.net.URL
import java.text.SimpleDateFormat
import java.util.*
class ManualSearchActivity : AppCompatActivity()
{
val API : String = "your api"
val EnterCityEditText: String = findViewById<EditText>(R.id.enter_city_edit_text).text.toString()
override fun onCreate(savedInstanceState: Bundle?)
{
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_manual_search)
val SearchCityButton = findViewById<Button>(R.id.button_search_city)
SearchCityButton.setOnClickListener(View.OnClickListener { weatherCall().execute() })
}
inner class weatherCall() : AsyncTask<String, Void, String>()
{
override fun onPreExecute()
{
super.onPreExecute()
findViewById<ProgressBar>(R.id.loader).visibility = View.VISIBLE
findViewById<RelativeLayout>(R.id.mainRelativeContainer).visibility = View.GONE
findViewById<TextView>(R.id.ErrorText).visibility = View.GONE
}
override fun doInBackground(vararg p0: String?): String?
{
var response:String?
try
{
response = URL( "https://api.openweathermap.org/data/2.5/weather?q=$EnterCityEditText&units=metric&APPID=yourapi").readText(Charsets.UTF_8)
}
catch (e: Exception)
{
response = null
}
return response
}
override fun onPostExecute(result: String?)
{
super.onPostExecute(result)
try
{
//JSON Return Values from the API
val jsonObj = JSONObject(result)
val main = jsonObj.getJSONObject("main")
val sys = jsonObj.getJSONObject("sys")
val wind = jsonObj.getJSONObject("wind")
val weather = jsonObj.getJSONArray("weather").getJSONObject(0)
val updatedAt:Long = jsonObj.getLong("dt")
val updatedAtText = "Updated at: "+ SimpleDateFormat("dd/MM/yyyy hh:mm a", Locale.ENGLISH).format(Date(updatedAt*1000))
val temp = main.getString("temp")+"°C"
val tempMin = "Min Temp: " + main.getString("temp_min")+"°C"
val tempMax = "Max Temp: " + main.getString("temp_max")+"°C"
val pressure = main.getString("pressure")
val humidity = main.getString("humidity")
val sunrise:Long = sys.getLong("sunrise")
val sunset:Long = sys.getLong("sunset")
val windSpeed = wind.getString("speed")
val weatherDescription = weather.getString("description")
val address = jsonObj.getString("name")+", "+sys.getString("country")
/* Populating extracted data into our views */
findViewById<TextView>(R.id.location_xml_id).text = address
findViewById<TextView>(R.id.updated_at_xml_id).text = updatedAtText
findViewById<TextView>(R.id.status_xml_id).text = weatherDescription.capitalize()
findViewById<TextView>(R.id.temperature_xml_id).text = temp
findViewById<TextView>(R.id.min_temp_xml_id).text = tempMin
findViewById<TextView>(R.id.max_temp_xml_id).text = tempMax
findViewById<TextView>(R.id.sunrise).text = SimpleDateFormat("hh:mm a", Locale.ENGLISH).format(Date(sunrise*1000))
findViewById<TextView>(R.id.sunset).text = SimpleDateFormat("hh:mm a", Locale.ENGLISH).format(Date(sunset*1000))
findViewById<TextView>(R.id.wind).text = windSpeed
findViewById<TextView>(R.id.pressure).text = pressure
findViewById<TextView>(R.id.humidity).text = humidity
/* Views populated, Hiding the loader, Showing the main design */
findViewById<ProgressBar>(R.id.loader).visibility = View.GONE
findViewById<RelativeLayout>(R.id.mainRelativeContainer).visibility = View.VISIBLE
} catch (e: Exception) {
findViewById<ProgressBar>(R.id.loader).visibility = View.GONE
findViewById<TextView>(R.id.ErrorText).visibility = View.VISIBLE
}
}
}
}
activity_manual_search.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@drawable/gradient_bg"
tools:context=".ManualSearchActivity">
<RelativeLayout
android:id="@+id/mainRelativeContainer"
android:visibility="visible"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="@+id/locationContainer"
android:orientation="vertical"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/enter_city_text"
android:text="Enter City Name: "
android:textSize="25sp"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<EditText
android:id="@+id/enter_city_edit_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/enter_city_text"
android:maxLines="1"
android:singleLine="true"/>
<Button
android:id="@+id/button_search_city"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Search for City"
android:layout_gravity="center"
android:layout_below="@+id/enter_city_edit_text"
android:layout_centerHorizontal="true"
android:textColor="#ffffff"
android:background="#0048ff"/>
<TextView
android:id="@+id/location_xml_id"
android:textSize="25sp"
android:text="Location"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/updated_at_xml_id"
android:textSize="15sp"
android:text="Updated at"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<LinearLayout
android:id="@+id/overviewContainer"
android:orientation="vertical"
android:layout_centerInParent="true"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/status_xml_id"
android:textSize="35sp"
android:layout_gravity="center"
android:text="Clear Sky"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/temperature_xml_id"
android:textSize="70sp"
android:fontFamily="sans-serif-thin"
android:layout_gravity="center"
android:text="Temperature"
android:gravity="center"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<LinearLayout
android:id="@+id/temperature_min_max_xml_id"
android:orientation="horizontal"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/min_temp_xml_id"
android:text="Min Temperature"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<Space
android:layout_width="50dp"
android:layout_height="wrap_content">
</Space>
<TextView
android:id="@+id/max_temp_xml_id"
android:text="Max Temperature"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
</LinearLayout>
<LinearLayout
android:id="@+id/detailsContainer"
android:orientation="vertical"
android:layout_alignParentBottom="true"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="horizontal"
android:weightSum="3"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="@drawable/sunrise"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Sunrise"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/sunrise"
android:textSize="14sp"
android:text="AM"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="@drawable/sunset"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Sunset"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/sunset"
android:textSize="14sp"
android:text="PM"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="@drawable/wind"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Wind"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/wind"
android:textSize="14sp"
android:text="Wind"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
</LinearLayout>
<Space
android:layout_width="wrap_content"
android:layout_height="10dp"></Space>
<LinearLayout
android:orientation="horizontal"
android:weightSum="3"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="@drawable/pressure"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Pressure"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/pressure"
android:textSize="14sp"
android:text="Pressure"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="@drawable/humidity"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Humidity"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/humidity"
android:textSize="14sp"
android:text="Humidity"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
<LinearLayout
android:orientation="vertical"
android:layout_weight="1"
android:gravity="center"
android:padding="9dp"
android:background="#969696"
android:layout_width="0dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="25dp"
android:layout_height="25dp"
android:src="@drawable/info"
app:tint="#FFF">
</ImageView>
<Space
android:layout_width="wrap_content"
android:layout_height="5dp">
</Space>
<TextView
android:textSize="12sp"
android:text="Weather Forecast"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
<TextView
android:id="@+id/info"
android:textSize="14sp"
android:text="Next 10 days"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</LinearLayout>
<Space
android:layout_width="10dp"
android:layout_height="wrap_content">
</Space>
</LinearLayout>
</LinearLayout>
</RelativeLayout>
<ProgressBar
android:id="@+id/loader"
android:layout_centerInParent="true"
android:visibility="gone"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</ProgressBar>
<TextView
android:id="@+id/ErrorText"
android:layout_centerInParent="true"
android:text="Error couldn't connect ?"
android:visibility="gone"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
</TextView>
</RelativeLayout>
Error here:
E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.theweathertoday, PID: 18698 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.theweathertoday/com.example.theweathertoday.ManualSearchActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3365) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:223) at android.app.ActivityThread.main(ActivityThread.java:7656) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.pm.ApplicationInfo android.content.Context.getApplicationInfo()' on a null object reference at android.content.ContextWrapper.getApplicationInfo(ContextWrapper.java:173) at android.view.ContextThemeWrapper.getTheme(ContextThemeWrapper.java:174) at android.content.Context.obtainStyledAttributes(Context.java:744) at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:922) at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:889) at androidx.appcompat.app.AppCompatDelegateImpl.findViewById(AppCompatDelegateImpl.java:691) at androidx.appcompat.app.AppCompatActivity.findViewById(AppCompatActivity.java:264) at com.example.theweathertoday.ManualSearchActivity.<init>(ManualSearchActivity.kt:22) at java.lang.Class.newInstance(Native Method) at android.app.AppComponentFactory.instantiateActivity(AppComponentFactory.java:95) at androidx.core.app.CoreComponentFactory.instantiateActivity(CoreComponentFactory.java:45) at android.app.Instrumentation.newActivity(Instrumentation.java:1253) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3353) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3601) at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2066) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:223) at android.app.ActivityThread.main(ActivityThread.java:7656) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
I am trying to pass a value from an edit text to a function, that value is the city name
You can see it inside the URL $EnterCityEditText, I converted the Edit Text entry to String I guess ?
A city name should appear and replace the placeholder value of course
Edit this is the solution, Thanks for David Wasser for hinting
override fun doInBackground(vararg p0: String?): String?
{
var response:String?
try
{
val EnterCityEditText = findViewById<EditText>(R.id.enter_city_edit_text).text.toString()
response = URL( "https://api.openweathermap.org/data/2.5/weather?q=$EnterCityEditText&units=metric&APPID=yourapi").readText(Charsets.UTF_8)
}
catch (e: Exception)
{
response = null
}
return response
}
This is your problem:
val EnterCityEditText: String = findViewById<EditText>(R.id.enter_city_edit_text).text.toString()
You've declared this variable as a member variable in your class. When the instance of the class is instantiated, Android attempts to initialize this variable by calling findViewById(). This fails because the Activity has not yet been completely initialized (onCreate() has not yet been called) and you must also wait until after setContentView() has been called.
Move the initialization of the variable into onCreate() after you have called setContentView().