Question

I’m quite new to programming and have just hit a simple road block that is holding me up. I am trying to have a button from my main activity call up another activity. I’ve researched but as yet I haven’t found something to work (probably really simple and stupid). Any help would be appreciated. I’ve included the code for my main activity. Thank you

package com.example.valentinetimer;


import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;


public class CardFront extends Activity implements OnClickListener {

    private static final String TAG = null;

    Button openButton;

    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.cardfrontxml);

    Log.d(TAG, "onCreate");

    //Button
    openButton = (Button) findViewById(R.id.openButton);
    openButton.setOnClickListener(this);

    this.setContentView(R.layout.cardfrontxml);
    this.openButton = (Button)this.findViewById(R.id.openButton);
    this.openButton.setOnClickListener(new OnClickListener()
    {
        @Override
        public void onClick(View v)
        {
            Log.d(TAG, "Click Event");

            Intent intent = new Intent (null, CardContent.class);
            startActivity (intent);
        }
    });
    //End Button

}

    @Override
    public void onClick(View v)
    {
        // TODO Auto-generated method stub  
    }
}

LogCat:

02-08 10:18:51.927: E/AndroidRuntime(2494): FATAL EXCEPTION: main
02-08 10:18:51.927: E/AndroidRuntime(2494): android.content.ActivityNotFoundException:          Unable to find explicit activity class   {com.example.valentinetimer/com.example.valentinetimer.CardContent}; have you declared this   activity in your AndroidManifest.xml?
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.app.Instrumentation.checkStartActivityResult(Instrumentation.java:1504)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.app.Instrumentation.execStartActivity(Instrumentation.java:1382)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.app.Activity.startActivityForResult(Activity.java:3095)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.app.Activity.startActivity(Activity.java:3201)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at com.example.valentinetimer.CardFront$1.onClick(CardFront.java:42)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.view.View.performClick(View.java:3110)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.view.View$PerformClick.run(View.java:11928)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.os.Handler.handleCallback(Handler.java:587)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.os.Handler.dispatchMessage(Handler.java:92)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.os.Looper.loop(Looper.java:132)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at android.app.ActivityThread.main(ActivityThread.java:4025)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at java.lang.reflect.Method.invokeNative(Native Method)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at java.lang.reflect.Method.invoke(Method.java:491)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
02-08 10:18:51.927: E/AndroidRuntime(2494):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

The problem is that your CardContent class is not specified in your manifest correctly. Please add this to your manifest in the application tag:

<activity
    android:name=".CardContent">
</activity>