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eamonamon
Courses Plus Student 2,863 PointsSimple App
Hello i have done what you have said but the error is not changing see code !:
package com.example.ballshaker;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Declare out view variables
TextView answerLable = findViewById(R.id.textView1);
Button getAnswerButton;
getAnswerButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
String answer = "";
answerLabel.setText(answer);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
3 Answers
Ben Jakuben
Treehouse TeacherCheck out these lines in your onCreate() method:
Button getAnswerButton;
getAnswerButton.setOnClickListener(new View.OnClickListener() {
The first line declares a Button variable but never sets it, meaning it is null, or empty. The next line tries to use it, but it hasn't been set yet. You simply need to set it on the first line in the same manner as how you are setting the TextView variable on the line above it.
eamonamon
Courses Plus Student 2,863 PointsTried it but nothing .. ?
Ben Jakuben
Treehouse TeacherCan you paste in the code you've tried?
eamonamon
Courses Plus Student 2,863 Pointspackage com.example.ballshaker;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;
public class MainActivity extends ClassBody
ClassBody
protected void ClassBody(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Declare out view variables
TextView answerLable = findViewById(R.id.textView1);
Button getAnswerButton;
getAnswerButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
String answer = "";
answerLabel.setText(answer);
}
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
Ben Jakuben
Treehouse TeacherOkay, in this code you still haven't set the Button variable. In the video we end up with this line of code below. Since yours isn't doing this, your Button is never being set, and you get an error trying to do anything with it (like trying to set an OnClickListener to it).
Button getAnswerButton = (Button)findViewById(R.id.button1);