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Android Build a Simple Android App (retired 2014) Learning the Language Introduction to Arrays

jason zheng
jason zheng
1,520 Points
Posted by jason zheng
jason zheng
1,520 Points

Need help

I followed all the instructions for some reason my emulator keep telling me " unfortunately, crystal ball has stopped. "

3 Answers

Calvin Nix
Calvin Nix
43,828 Points
Calvin Nix
Calvin Nix
43,828 Points

Hey Jason,

Could you please post the error message from logcat?

jason zheng
jason zheng
1,520 Points
jason zheng
jason zheng
1,520 Points

06-05 02:30:45.476: D/gralloc_goldfish(1107): Emulator without GPU emulation detected. 06-05 02:30:52.396: I/Choreographer(1107): Skipped 43 frames! The application may be doing too much work on its main thread. 06-05 02:32:08.656: D/AndroidRuntime(1152): Shutting down VM 06-05 02:32:08.656: W/dalvikvm(1152): threadid=1: thread exiting with uncaught exception (group=0xb2aebba8) 06-05 02:32:08.666: E/AndroidRuntime(1152): FATAL EXCEPTION: main 06-05 02:32:08.666: E/AndroidRuntime(1152): Process: com.example.crystalball, PID: 1152 06-05 02:32:08.666: E/AndroidRuntime(1152): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.crystalball/com.example.crystalball.MainActivity}: java.lang.NullPointerException 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195) 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.app.ActivityThread.access$800(ActivityThread.java:135) 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.os.Handler.dispatchMessage(Handler.java:102) 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.os.Looper.loop(Looper.java:136) 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.app.ActivityThread.main(ActivityThread.java:5017) 06-05 02:32:08.666: E/AndroidRuntime(1152): at java.lang.reflect.Method.invokeNative(Native Method) 06-05 02:32:08.666: E/AndroidRuntime(1152): at java.lang.reflect.Method.invoke(Method.java:515) 06-05 02:32:08.666: E/AndroidRuntime(1152): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 06-05 02:32:08.666: E/AndroidRuntime(1152): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 06-05 02:32:08.666: E/AndroidRuntime(1152): at dalvik.system.NativeStart.main(Native Method) 06-05 02:32:08.666: E/AndroidRuntime(1152): Caused by: java.lang.NullPointerException 06-05 02:32:08.666: E/AndroidRuntime(1152): at com.example.crystalball.MainActivity.onCreate(MainActivity.java:31) 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.app.Activity.performCreate(Activity.java:5231) 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 06-05 02:32:08.666: E/AndroidRuntime(1152): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159) 06-05 02:32:08.666: E/AndroidRuntime(1152): ... 11 more 06-05 02:32:24.396: I/Process(1152): Sending signal. PID: 1152 SIG: 9 06-05 02:33:23.326: D/AndroidRuntime(1199): Shutting down VM 06-05 02:33:23.326: W/dalvikvm(1199): threadid=1: thread exiting with uncaught exception (group=0xb2aebba8) 06-05 02:33:23.336: E/AndroidRuntime(1199): FATAL EXCEPTION: main 06-05 02:33:23.336: E/AndroidRuntime(1199): Process: com.example.crystalball, PID: 1199 06-05 02:33:23.336: E/AndroidRuntime(1199): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.crystalball/com.example.crystalball.MainActivity}: java.lang.NullPointerException 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195) 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.app.ActivityThread.access$800(ActivityThread.java:135) 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.os.Handler.dispatchMessage(Handler.java:102) 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.os.Looper.loop(Looper.java:136) 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.app.ActivityThread.main(ActivityThread.java:5017) 06-05 02:33:23.336: E/AndroidRuntime(1199): at java.lang.reflect.Method.invokeNative(Native Method) 06-05 02:33:23.336: E/AndroidRuntime(1199): at java.lang.reflect.Method.invoke(Method.java:515) 06-05 02:33:23.336: E/AndroidRuntime(1199): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 06-05 02:33:23.336: E/AndroidRuntime(1199): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 06-05 02:33:23.336: E/AndroidRuntime(1199): at dalvik.system.NativeStart.main(Native Method) 06-05 02:33:23.336: E/AndroidRuntime(1199): Caused by: java.lang.NullPointerException 06-05 02:33:23.336: E/AndroidRuntime(1199): at com.example.crystalball.MainActivity.onCreate(MainActivity.java:31) 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.app.Activity.performCreate(Activity.java:5231) 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 06-05 02:33:23.336: E/AndroidRuntime(1199): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159) 06-05 02:33:23.336: E/AndroidRuntime(1199): ... 11 more 06-05 02:33:29.066: I/Process(1199): Sending signal. PID: 1199 SIG: 9 06-05 02:38:16.366: D/AndroidRuntime(1247): Shutting down VM 06-05 02:38:16.366: W/dalvikvm(1247): threadid=1: thread exiting with uncaught exception (group=0xb2aebba8) 06-05 02:38:16.376: E/AndroidRuntime(1247): FATAL EXCEPTION: main 06-05 02:38:16.376: E/AndroidRuntime(1247): Process: com.example.crystalball, PID: 1247 06-05 02:38:16.376: E/AndroidRuntime(1247): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.crystalball/com.example.crystalball.MainActivity}: java.lang.NullPointerException 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195) 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.app.ActivityThread.access$800(ActivityThread.java:135) 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.os.Handler.dispatchMessage(Handler.java:102) 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.os.Looper.loop(Looper.java:136) 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.app.ActivityThread.main(ActivityThread.java:5017) 06-05 02:38:16.376: E/AndroidRuntime(1247): at java.lang.reflect.Method.invokeNative(Native Method) 06-05 02:38:16.376: E/AndroidRuntime(1247): at java.lang.reflect.Method.invoke(Method.java:515) 06-05 02:38:16.376: E/AndroidRuntime(1247): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 06-05 02:38:16.376: E/AndroidRuntime(1247): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 06-05 02:38:16.376: E/AndroidRuntime(1247): at dalvik.system.NativeStart.main(Native Method) 06-05 02:38:16.376: E/AndroidRuntime(1247): Caused by: java.lang.NullPointerException 06-05 02:38:16.376: E/AndroidRuntime(1247): at com.example.crystalball.MainActivity.onCreate(MainActivity.java:31) 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.app.Activity.performCreate(Activity.java:5231) 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 06-05 02:38:16.376: E/AndroidRuntime(1247): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159) 06-05 02:38:16.376: E/AndroidRuntime(1247): ... 11 more 06-05 02:40:40.296: D/AndroidRuntime(1291): Shutting down VM 06-05 02:40:40.296: W/dalvikvm(1291): threadid=1: thread exiting with uncaught exception (group=0xb2aebba8) 06-05 02:40:40.306: E/AndroidRuntime(1291): FATAL EXCEPTION: main 06-05 02:40:40.306: E/AndroidRuntime(1291): Process: com.example.crystalball, PID: 1291 06-05 02:40:40.306: E/AndroidRuntime(1291): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.crystalball/com.example.crystalball.MainActivity}: java.lang.NullPointerException 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195) 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.app.ActivityThread.access$800(ActivityThread.java:135) 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.os.Handler.dispatchMessage(Handler.java:102) 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.os.Looper.loop(Looper.java:136) 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.app.ActivityThread.main(ActivityThread.java:5017) 06-05 02:40:40.306: E/AndroidRuntime(1291): at java.lang.reflect.Method.invokeNative(Native Method) 06-05 02:40:40.306: E/AndroidRuntime(1291): at java.lang.reflect.Method.invoke(Method.java:515) 06-05 02:40:40.306: E/AndroidRuntime(1291): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 06-05 02:40:40.306: E/AndroidRuntime(1291): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 06-05 02:40:40.306: E/AndroidRuntime(1291): at dalvik.system.NativeStart.main(Native Method) 06-05 02:40:40.306: E/AndroidRuntime(1291): Caused by: java.lang.NullPointerException 06-05 02:40:40.306: E/AndroidRuntime(1291): at com.example.crystalball.MainActivity.onCreate(MainActivity.java:31) 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.app.Activity.performCreate(Activity.java:5231) 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 06-05 02:40:40.306: E/AndroidRuntime(1291): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159) 06-05 02:40:40.306: E/AndroidRuntime(1291): ... 11 more 06-05 02:40:53.716: I/Process(1291): Sending signal. PID: 1291 SIG: 9 06-05 02:41:19.226: D/gralloc_goldfish(1339): Emulator without GPU emulation detected. 06-05 02:43:14.516: D/AndroidRuntime(1383): Shutting down VM 06-05 02:43:14.516: W/dalvikvm(1383): threadid=1: thread exiting with uncaught exception (group=0xb2aebba8) 06-05 02:43:14.526: E/AndroidRuntime(1383): FATAL EXCEPTION: main 06-05 02:43:14.526: E/AndroidRuntime(1383): Process: com.example.crystalball, PID: 1383 06-05 02:43:14.526: E/AndroidRuntime(1383): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.crystalball/com.example.crystalball.MainActivity}: java.lang.NullPointerException 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195) 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.app.ActivityThread.access$800(ActivityThread.java:135) 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.os.Handler.dispatchMessage(Handler.java:102) 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.os.Looper.loop(Looper.java:136) 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.app.ActivityThread.main(ActivityThread.java:5017) 06-05 02:43:14.526: E/AndroidRuntime(1383): at java.lang.reflect.Method.invokeNative(Native Method) 06-05 02:43:14.526: E/AndroidRuntime(1383): at java.lang.reflect.Method.invoke(Method.java:515) 06-05 02:43:14.526: E/AndroidRuntime(1383): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 06-05 02:43:14.526: E/AndroidRuntime(1383): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 06-05 02:43:14.526: E/AndroidRuntime(1383): at dalvik.system.NativeStart.main(Native Method) 06-05 02:43:14.526: E/AndroidRuntime(1383): Caused by: java.lang.NullPointerException 06-05 02:43:14.526: E/AndroidRuntime(1383): at com.example.crystalball.MainActivity.onCreate(MainActivity.java:31) 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.app.Activity.performCreate(Activity.java:5231) 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 06-05 02:43:14.526: E/AndroidRuntime(1383): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159) 06-05 02:43:14.526: E/AndroidRuntime(1383): ... 11 more 06-05 02:45:48.016: D/AndroidRuntime(1427): Shutting down VM 06-05 02:45:48.016: W/dalvikvm(1427): threadid=1: thread exiting with uncaught exception (group=0xb2aebba8) 06-05 02:45:48.026: E/AndroidRuntime(1427): FATAL EXCEPTION: main 06-05 02:45:48.026: E/AndroidRuntime(1427): Process: com.example.crystalball, PID: 1427 06-05 02:45:48.026: E/AndroidRuntime(1427): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.crystalball/com.example.crystalball.MainActivity}: java.lang.NullPointerException 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195) 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245) 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.app.ActivityThread.access$800(ActivityThread.java:135) 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196) 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.os.Handler.dispatchMessage(Handler.java:102) 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.os.Looper.loop(Looper.java:136) 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.app.ActivityThread.main(ActivityThread.java:5017) 06-05 02:45:48.026: E/AndroidRuntime(1427): at java.lang.reflect.Method.invokeNative(Native Method) 06-05 02:45:48.026: E/AndroidRuntime(1427): at java.lang.reflect.Method.invoke(Method.java:515) 06-05 02:45:48.026: E/AndroidRuntime(1427): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 06-05 02:45:48.026: E/AndroidRuntime(1427): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 06-05 02:45:48.026: E/AndroidRuntime(1427): at dalvik.system.NativeStart.main(Native Method) 06-05 02:45:48.026: E/AndroidRuntime(1427): Caused by: java.lang.NullPointerException 06-05 02:45:48.026: E/AndroidRuntime(1427): at com.example.crystalball.MainActivity.onCreate(MainActivity.java:29) 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.app.Activity.performCreate(Activity.java:5231) 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087) 06-05 02:45:48.026: E/AndroidRuntime(1427): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159) 06-05 02:45:48.026: E/AndroidRuntime(1427): ... 11 more

jason zheng
jason zheng
1,520 Points
jason zheng
jason zheng
1,520 Points

This is the code-----

package com.example.crystalball;

import java.util.Random;

import android.os.Bundle; import android.support.v4.app.Fragment; import android.support.v7.app.ActionBarActivity; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.Button; import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

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





     final TextView answerLabel =(TextView)findViewById(R.id.textView2);
Button answers =(Button)findViewById(R.id.button1);
answers.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View arg0) {
        String [] answers = {
                "It is certain",
                "It is decidely so",
                " All sign say Yes",
                " My reply is no",
                "It is not there yet",
                "Better not tell you yet",
                "cant answer now"
        };

        String answer = " ";
        Random Generator = new Random ();
        int randonNumber = Generator.nextInt(answers.length);

        answer = answers[randonNumber];
        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);
}

}

xml----

<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: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" >

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true" />

<Button
    android:id="@+id/button1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_below="@+id/textView2"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="16dp"
    android:text="Enlighten Me" />

</RelativeLayout>