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Android

Jonathan Grieve
MOD
Jonathan Grieve
Treehouse Moderator 91,253 Points
Posted by Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 91,253 Points

Android Extra Credit - getting user input

Here's my code from my extra credit attempt for the Interactive Story course. As you can see, it generates a scary runtime error when I attempt to tab the button associated with the EditText.

Or if you want to clone it on Github, here it is! https://github.com/jg-digital-media/android-user-input

My situation at the moment is I'm very stuck with my Android learning having completed the first 3 apps in the track. The Facts app, the story and the weather app.

In the main, it's got nothing to do with understanding what's been taught. The teaching is on point and superb. I'm afraid it's just my short term memory. My brain isn't built for remembering blocks of code. So, instead of committing things to memory, I of course, look up documentation where I can and keep snippets of code I deem helpful.

But is that enough?

The Extra credit task is simply to get text from different Android classes (EditText, RadioButton) etc and log it to the console or as a toast.

I wanted to tackle all of this on my own, but basically, I don't really know what I'm doing.

MainActivity.java 
package uk.co.jonniegrieve.androiduserinput;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.Spinner;
import android.widget.Switch;
import android.widget.Toast;
import android.widget.ToggleButton;

import static uk.co.jonniegrieve.androiduserinput.R.id.editTextButton;

public class MainActivity extends AppCompatActivity {

    //declare variables
    private EditText mEditText;
    private CheckBox mCheckBox;
    private RadioButton mRadioButton;
    private Switch mSwitch;
    private ToggleButton mToggleButton;
    private Spinner mSpinner;

    private Button editTextButton;
    private Button checkboxButton;
    private Button radioButton;
    private Button switchButton;
    private Button toggleButton;
    private Button spinnerButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mEditText = (EditText) findViewById(R.id.editText);
        mCheckBox = (CheckBox) findViewById(R.id.checkbox);
        mRadioButton = (RadioButton) findViewById(R.id.radioButton);
        mSwitch = (Switch) findViewById(R.id.switchView);
        mToggleButton = (ToggleButton) findViewById(R.id.toggleButton);
        mSpinner = (Spinner) findViewById(R.id.spinner);

        View.OnClickListener listener = new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //code goes here
                String name = mEditText.getText().toString();
                Toast.makeText(MainActivity.this, name, Toast.LENGTH_LONG).show();

            }
        };

        editTextButton.setOnClickListener(listener);





    }
activity_main.xml 
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    android:id="@+id/activity_main"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="uk.co.jonniegrieve.androiduserinput.MainActivity"
    tools:background="#68ff6d">

    <TextView
        android:text="Getting User Input TextView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/inputTextView"
        android:textAlignment="center"
        android:textStyle="normal|bold"
        android:textColor="#459b14"
        android:layout_below="@+id/mainTitleTextView"
        android:layout_centerHorizontal="true"/>

    <TextView
        android:text="Textbox"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginLeft="11dp"
        android:layout_marginStart="11dp"
        android:layout_marginTop="29dp"
        android:id="@+id/textView2"
        android:layout_below="@+id/inputTextView"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"/>

    <TextView
        android:text="Radio Button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/Checkbox"
        android:layout_alignLeft="@+id/Checkbox"
        android:layout_alignStart="@+id/Checkbox"
        android:layout_marginTop="27dp"
        android:id="@+id/textView4"/>

    <TextView
        android:text="Toggle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/Switch"
        android:layout_alignLeft="@+id/Switch"
        android:layout_alignStart="@+id/Switch"
        android:layout_marginTop="32dp"
        android:id="@+id/Toggle"/>

    <TextView
        android:text="checkbox"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="30dp"
        android:id="@+id/Checkbox"
        android:layout_below="@+id/textView2"
        android:layout_alignLeft="@+id/textView2"
        android:layout_alignStart="@+id/textView2"/>

    <CheckBox
        android:text="CheckBox"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/checkBox2"
        android:layout_alignBaseline="@+id/Checkbox"
        android:layout_alignBottom="@+id/Checkbox"
        android:layout_toRightOf="@+id/textView4"
        android:layout_toEndOf="@+id/textView4"/>

    <Button
        android:text="Show Value"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/checkBox2"
        android:layout_alignLeft="@+id/editTextButton"
        android:layout_alignStart="@+id/editTextButton"
        android:id="@+id/checkboxButton"/>

    <EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:inputType="textPersonName"
        android:text="Name"
        android:ems="10"
        android:id="@+id/editText"
        android:layout_alignBaseline="@+id/textView2"
        android:layout_alignBottom="@+id/textView2"
        android:layout_toLeftOf="@+id/editTextButton"
        android:layout_alignLeft="@+id/inputTextView"
        android:layout_alignStart="@+id/inputTextView"/>

    <RadioButton
        android:text="RadioButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/checkboxButton"
        android:layout_toRightOf="@+id/textView4"
        android:layout_toEndOf="@+id/textView4"
        android:layout_marginLeft="14dp"
        android:layout_marginStart="14dp"
        android:id="@+id/radioButton"/>

    <Button
        android:text="Show Value"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/radioButton"
        android:layout_alignLeft="@+id/radioButton"
        android:layout_alignStart="@+id/radioButton"
        android:id="@+id/switchButton"/>

    <ToggleButton
        android:text="ToggleButton"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/toggleButton"
        android:layout_alignBaseline="@+id/Toggle"
        android:layout_alignBottom="@+id/Toggle"
        android:layout_alignRight="@+id/checkBox2"
        android:layout_alignEnd="@+id/checkBox2"/>

    <Button
        android:text="Show Value"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/toggleButton"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:layout_below="@+id/switchButton"/>

    <TextView
        android:text="Switch"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/Switch"
        android:layout_below="@+id/radioButton"
        android:layout_alignRight="@+id/Checkbox"
        android:layout_alignEnd="@+id/Checkbox"
        android:layout_alignLeft="@+id/textView4"
        android:layout_alignStart="@+id/textView4"/>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="ANDROID PROJECT"
        android:id="@+id/mainTitleTextView"
        android:textAlignment="center"
        android:textStyle="normal|bold"
        android:textSize="30sp"
        android:textColor="#459b14"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"/>

    <TextView
        android:text="Spinner"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/toggleButton"
        android:layout_alignLeft="@+id/Toggle"
        android:layout_alignStart="@+id/Toggle"
        android:id="@+id/textView9"/>

    <Button
        android:text="Show Value"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/editTextButton"
        android:layout_alignBaseline="@+id/editText"
        android:layout_alignBottom="@+id/editText"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"/>

    <Switch
        android:text="Switch"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/switchView"
        android:layout_alignTop="@+id/Switch"
        android:layout_alignLeft="@+id/editText"
        android:layout_alignStart="@+id/editText"/>

    <Button
        android:text="Show Value"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/radioButton"
        android:layout_below="@+id/checkboxButton"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"/>

    <Button
        android:text="Show Value"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/spinnerButton"
        android:layout_below="@+id/toggleButton"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"/>

    <Spinner
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/spinner"
        android:layout_alignBottom="@+id/spinnerButton"
        android:layout_alignRight="@+id/textView9"
        android:layout_alignEnd="@+id/textView9"/>

</RelativeLayout>

1 Answer

Seth Kroger
Seth Kroger
56,413 Points
Seth Kroger
Seth Kroger
56,413 Points

I think you have a good start on it. I cloned your repo and ran it. It looks like the app is crashing because you're forgetting to initialize the Show Value buttons as well as the inputs. That leaves them null, hence a NullPointerException when you try to set a listener. The second thing that's really easy to miss in all the scrolling is there are two stack traces that get spit out. Before the actual crash you get:

>>>03-16 15:05:54.829 1921-1921/com.android.launcher3 E/CellLayout: Ignoring an error while restoring a view instance state

>>>java.lang.IllegalArgumentException: Wrong state class, expecting View State but received class android.appwidget.AppWidgetHostView$ParcelableSparseArray instead. This usually happens when two views of different type have the same id in the same hierarchy. This view's id is id/0x4. Make sure other views do not use the same id.

Looking at your layout you're using 'radioButton' as as the id for both the RadioButton and it's Show Value button, and likewise with 'toggleButton'.

Yeah, Android stack traces can be pretty scary, but it gets better with practice. The two big things to look for are the actual exception message and the first point your code instead of Android code shows up. Most of the stack trace beyond those two pieces is usually irrelevant.

Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 91,253 Points
Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 91,253 Points

Thanks for your responses. :)

When I say "I don't know what I'm doing" clearly I know some things because and I have knowledge in my brain. It's just what happens when I'm let "loose in the wild" so to speak. It's a huge corner I've yet to turn

So the first things to try are Initialise "Show Value" buttons

Look at the id's for radio button and toggleButtons and make them unique

Hopefully after that, I'm pretty confident I can incrementally (for want of a better word) add the toasts for each input one by one.

I'll let you know how I'm getting on but I'm downloading AS 4.3 and have major updates that are taking an age to come through! :)

Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 91,253 Points
Jonathan Grieve
Jonathan Grieve
Treehouse Moderator 91,253 Points

Well I've just pushed up my latest changes, getting text from the EditText. Looking forward to learning how to get input from the rest of the controls.

Thanks for the nudge! :)