global varible gives ClassCastException

[shawn peter]

this is my main class

package com.android.test;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;

public class MainActivity extends Activity {

	String ID[];
	String NoOfTimes[];
	String TIME[];

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

		try{
		Global global = ((Global)getApplicationContext());
		
		
		}catch(Exception e){
			e.printStackTrace();
		}
	}

	public void mobitel() {

	}

	@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;
	}

}

this is manifest file

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.android.test"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="10"
        android:targetSdkVersion="10" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.android.test.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity android:name="Global" >
        </activity>
    </application>

</manifest>

below is the error i am getting

07-16 17:07:12.902: W/System.err(15079): java.lang.ClassCastException: android.app.Application
07-16 17:07:12.902: W/System.err(15079): 	at com.android.test.MainActivity.onCreate(MainActivity.java:19)
07-16 17:07:12.902: W/System.err(15079): 	at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
07-16 17:07:12.902: W/System.err(15079): 	at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1623)
07-16 17:07:12.902: W/System.err(15079): 	at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1675)
07-16 17:07:12.902: W/System.err(15079): 	at android.app.ActivityThread.access$1500(ActivityThread.java:121)
07-16 17:07:12.902: W/System.err(15079): 	at android.app.ActivityThread$H.handleMessage(ActivityThread.java:943)
07-16 17:07:12.902: W/System.err(15079): 	at android.os.Handler.dispatchMessage(Handler.java:99)
07-16 17:07:12.902: W/System.err(15079): 	at android.os.Looper.loop(Looper.java:130)
07-16 17:07:12.902: W/System.err(15079): 	at android.app.ActivityThread.main(ActivityThread.java:3701)
07-16 17:07:12.902: W/System.err(15079): 	at java.lang.reflect.Method.invokeNative(Native Method)
07-16 17:07:12.902: W/System.err(15079): 	at java.lang.reflect.Method.invoke(Method.java:507)
07-16 17:07:12.902: W/System.err(15079): 	at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
07-16 17:07:12.902: W/System.err(15079): 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:624)
07-16 17:07:12.902: W/System.err(15079): 	at dalvik.system.NativeStart.main(Native Method)
07-16 17:07:58.862: W/ActivityThread(15375): Application com.android.test is waiting for the debugger on port 8100...

[Ulf Dittmer]

Something is amiss: the stack trace mentions line 93 in the onCreate method of MainActivity, but the code you posted is way shorter. Which one is line 93?

[Ulf Dittmer]

Ah, that stack trace makes more sense. You're not setting the app context class to anything called "Global" in the manifest, so it's android.app.Application - nothing mysterious about it.

[shawn peter]

But i have added the below to manifest

  <activity android:name="Global" >  
        </activity>  

[Steve Luke]

sameera liyanage wrote:But i have added the below to manifest

  <activity android:name="Global" >  
        </activity>  

Yes, you defined an Activity with the name Global. But you try to get the application (Global global = ((Global)getApplicationContext());) and assign it to Global. The Application Context is a subclass of android.app.Application, not an activity.

Read this document on the Android Manifest: http://developer.android.com/guide/topics/manifest/manifest-intro.html. It has links on the application element, which is what you would use to override the class used for the Application Context.

[shawn peter]

I change the manifest code as below.Now it's fine.Anyway if i have two Global classes how to add them to manifest file.Because we can't add two name parameters to manifest file

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.android.test"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="10"
        android:targetSdkVersion="10" />

    <application
        android:name="Global"
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.android.test.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        
    </application>

</manifest>

[Ulf Dittmer]

An app can only have a single app context class. What are you trying to accomplish by having two? That would seem to make things more difficult, instead of simpler.

[shawn peter]

below is my Global class

package com.android.test;

import android.app.Application;

public class Global extends Application {

	String ID[];
	String NoOfTimes[];
	String TIME[];

	public String[] getID() {
		return ID;
	}

	public void setID(String[] iD) {
		ID = iD;
	}

	public String[] getNoOfTimes() {
		return NoOfTimes;
	}

	public void setNoOfTimes(String[] noOfTimes) {
		NoOfTimes = noOfTimes;
	}

	public String[] getTIME() {
		return TIME;
	}

	public void setTIME(String[] tIME) {
		TIME = tIME;
	}

}

My problem is ,in the set method it just initialize he size of arra.it's ok.But how to add element to them?

[Ulf Dittmer]

You can either call getTIME() (for example), and then do whatever needs doing with the array it returns, or add a method that addToTIME(String) that adds that string as the last element of the TIME array.

Two remarks, though: variables have lowercase names. While uppercase is permissible, it is so exceedingly rare that people who look at your code will wonder what's going on. Uppercase is generally used for names of constants.

Secondly, if you don't know beforehand how many elements an array has, it's probably better to use a Collection instead of an array - maybe an ArrayList<String>. That makes it easy to add elements at the end, and to find out how many elements it already contains.