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Android Build a Simple Android App (retired 2014) Pretty Little Things Customizing Buttons and Labels

Unfortunately, Crystal Ball has stopped

I am not getting an errors in my code. Here are my two java files and the info from the LogCat.


package com.example.crystalball;

import android.app.Activity; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.widget.Button; import android.widget.TextView;

public class MainActivity extends Activity { private CrystalBall mCrystalBall = new CrystalBall();

protected void onCreate(Bundle savedInstanceState) {

    // Declare our view variables
    final TextView answerLabel = (TextView) findViewById(R.id.textView1);
    Button getAnswerButton = (Button) findViewById(R.id.button1);

    getAnswerButton.setOnClickListener(new View.OnClickListener() {

        public void onClick(View v) {
            String answer = mCrystalBall.getAnAnswer();             

            // Update the label with our dynamic 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);



package com.example.crystalball;

import java.util.Random;

public class CrystalBall { // Member variables (properties about the object) public String[] mAnswers = { "It is certain", "It is decidedly so", "All signs say YES", "The stars are not aligned", "My reply is no", "It is doubtful", "Better not tell you now", "Concentrate and ask again", "Unable to answer now"};

// Methods (abilities: things the object can do)
public String getAnAnswer() {

    String answer = "";

    // Randomly select one of three answers: Yes, No, or Maybe
    Random randomGenerator = new Random(); //Construct a new Random number generator
    int randomNumber = randomGenerator.nextInt(mAnswers.length);

    // Convert the randomNumber to a text answer
    answer = mAnswers[randomNumber];

    return answer;



08-14 11:52:48.973: D/dalvikvm(1087): GC_FOR_ALLOC freed 72K, 5% free 2909K/3052K, paused 71ms, total 83ms 08-14 11:52:48.983: I/dalvikvm-heap(1087): Grow heap (frag case) to 3.677MB for 811216-byte allocation 08-14 11:52:49.083: D/dalvikvm(1087): GC_FOR_ALLOC freed <1K, 4% free 3701K/3848K, paused 83ms, total 84ms 08-14 11:52:49.293: D/AndroidRuntime(1087): Shutting down VM 08-14 11:52:49.293: W/dalvikvm(1087): threadid=1: thread exiting with uncaught exception (group=0xb1a20ba8) 08-14 11:52:49.303: E/AndroidRuntime(1087): FATAL EXCEPTION: main 08-14 11:52:49.303: E/AndroidRuntime(1087): Process: com.example.crystalball, PID: 1087 08-14 11:52:49.303: E/AndroidRuntime(1087): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.crystalball/com.example.crystalball.MainActivity}: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.Button 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195) 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.app.ActivityThread.access$800(ActivityThread.java:135) 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.os.Handler.dispatchMessage(Handler.java:102) 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.os.Looper.loop(Looper.java:136) 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.app.ActivityThread.main(ActivityThread.java:5017) 08-14 11:52:49.303: E/AndroidRuntime(1087): at java.lang.reflect.Method.invokeNative(Native Method) 08-14 11:52:49.303: E/AndroidRuntime(1087): at java.lang.reflect.Method.invoke(Method.java:515) 08-14 11:52:49.303: E/AndroidRuntime(1087): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 08-14 11:52:49.303: E/AndroidRuntime(1087): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 08-14 11:52:49.303: E/AndroidRuntime(1087): at dalvik.system.NativeStart.main(Native Method) 08-14 11:52:49.303: E/AndroidRuntime(1087): Caused by: java.lang.ClassCastException: android.widget.TextView cannot be cast to android.widget.Button 08-14 11:52:49.303: E/AndroidRuntime(1087): at com.example.crystalball.MainActivity.onCreate(MainActivity.java:21) 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.app.Activity.performCreate(Activity.java:5231) 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 08-14 11:52:49.303: E/AndroidRuntime(1087): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159) 08-14 11:52:49.303: E/AndroidRuntime(1087): ... 11 more

1 Answer

Marlon Copeland
Marlon Copeland
1,675 Points

.ClassCastException: android.widget.TextView cannot be cast to android.widget.Button - Found that in the Log Cat. Make sure your button1 resource isn't actually a TextView.


It seems to be a button. I am not sure how to tell for sure that it is a button and not a TextView. It looks like a button and it says it is a button in the xml. Here is the xml code:

<RelativeLayout 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:background="@android:color/black" 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="com.example.crystalball.MainActivity$PlaceholderFragment" >

    android:src="@drawable/ball01" />

    android:text="Enlighten me!"
    android:typeface="serif" />

    android:textSize="32sp" />