测试时启动屏幕后应用程序强制关闭

Question

package com.ave;

import com.ave.R;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;



public class Menu extends Activity{
ImageButton select;    
int isClicked = 0;


        @Override
        protected void onCreate(Bundle savedInstanceState) {
                // TODO Auto-generated method stub
                super.onCreate(savedInstanceState);
                setContentView(R.layout.main);

                select = (ImageButton)findViewById(R.id.select);
        select.setOnClickListener(new OnClickListener() {

                public void onClick(View v) {
                     if (isClicked == 0){
                        select.setImageResource(R.drawable.select_pressed);
                        isClicked = 1;
                     }
                     else{
                        select.setImageResource(R.drawable.select);
                        isClicked = 0;
                     }
                }});
        }

        ImageButton audio;    
        int isClicked1 = 0;{

        audio = (ImageButton)findViewById(R.id.audio);
        audio.setOnClickListener(new OnClickListener() {

                public void onClick(View v) {
                     if (isClicked1 == 0){
                        audio.setImageResource(R.drawable.audio_pressed);
                        isClicked1 = 1;
                     }
                     else{
                        audio.setImageResource(R.drawable.audio);
                        isClicked1 = 0;
                     }
                 }
           });
         }
      }

============LogCat=================

E AndroidRuntime: FATAL EXCEPTION: main
E AndroidRuntime: java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.ave/com.ave.Menu}: java.lang.NullPointerException
E AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1618)
E AndroidRuntime:     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1716)
E AndroidRuntime:     at android.app.ActivityThread.access$1500(ActivityThread.java:124)
E AndroidRuntime:     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:968)
E AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:99)
E AndroidRuntime:     at android.os.Looper.loop(Looper.java:123)
E AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:3806)
E AndroidRuntime:     at java.lang.reflect.Method.invokeNative(Native Method)
E AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:507)
E AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
E AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
E AndroidRuntime:     at dalvik.system.NativeStart.main(Native Method)
E AndroidRuntime: Caused by: java.lang.NullPointerException
E AndroidRuntime:     at android.app.Activity.findViewById(Activity.java:1693)
E AndroidRuntime:     at com.ave.Menu.(Menu.java:41)
E AndroidRuntime:     at java.lang.Class.newInstanceImpl(Native Method)
E AndroidRuntime:     at java.lang.Class.newInstance(Class.java:1409)
E AndroidRuntime:     at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
E AndroidRuntime:     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1610)
E AndroidRuntime: ... 11 more

I have no errors within xml or class and everything is referenced properly but when i try to test the app through AVD or my phone it force stops after the splash screen. And produces what you see in the LogCat. Again no errors in the xml or classes and everything is referenced. So what am i doing wrong? Or what needs to be added. It all stopped working after adding the second imageButton method, but if i remove it. It works fine.

  <?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/droid_background">
    <TextView 
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_horizontal"
    android:text="@string/hello"
    android:textColor="#FFFFFF"
    android:textStyle="bold"/>
    <ImageButton 
android:src="@drawable/select"
android:id="@+id/select"
android:layout_height="30dp"
android:layout_width="120dp"
android:background="@null"
    android:layout_alignParentLeft="true"
android:layout_alignParentBottom="true"/>
    <ImageButton
android:src="@drawable/audio"
android:id="@+id/audio"
android:layout_height="30dp"
android:layout_width="120dp"
android:background="@null"
android:layout_alignParentRight="true"
android:layout_alignParentBottom="true"/>
    </RelativeLayout>'

Answer 1

Did you tried to run "Clean Up" to the project? Sometimes XML layouts needs to be regenerated in order app to work as expected.

Answer 2

Did you add your Activity to the AndroidManifest.xml file?

Answer 3

You have two ImageButtons with the id audio. Try renaming one.