Question

I am new to Android development and I want first to get the Hello World application running.
I am using Eclipse IDE and the Android 4.0.3 version 15 SDK. I copied everything from a tutorial site, but when I try to run the application on the virtual device I get this error:

[2012-02-01 11:31:23 - Android_test] Installation error: INSTALL_FAILED_OLDER_SDK
[2012-02-01 11:31:23 - Android_test] Please check logcat output for more details.
[2012-02-01 11:31:23 - Android_test] Launch canceled!

Here is my class in the com.maze.app package:
package com.maze.app;

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

public class HelloAndroid extends Activity{
  @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        TextView tv = new TextView(this);
        tv.setText("Hello, Android");
        setContentView(tv);

    }

}

and the AndroidManifest.xml:

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

<uses-sdk android:minSdkVersion="15" android:targetSdkVersion="@string/app_name"/>

<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name" >
    <activity android:name="HelloAndroid" android:launchMode="standard" android:enabled="true"></activity>
</application>

Here is the configuration of the Virtual Device:

Name: AndroidVD
CPU/ABI: ARM(armeabi-v7a)
Path: path\to\avd
Target: Android 4.0.3(API level 15)
Skin: WVGA800
hw.lcd.density: 240
hw.cpu.model: cortex-a8
vm.heapSize: 48
hw.ramSize:512

What is the problem?

EDIT:
The application is not running on the Virtual Device:
Here is what I get on LogCat(some of the lines):

D/PackageManager(92): New package installed in /data/app/com.maze.app-2.apk
D/dalvikvm(92): GC_CONCURRENT freed 660K, 9% free 11935K/12999K, paused 18ms+72ms
I/ActivityManager(92): Force stopping package com.maze.app uid=10040
D/BackupManagerService(92): Received broadcast Intent { act=android.intent.action.PACKAGE_REPLACED dat=package:com.maze.app flg=0x10000010 (has extras) }
V/BackupManagerService(92): updatePackageParticipantsLocked: com.maze.app

Answer 1

It is due to android:targetSdkVersion="@string/app_name" in your manifiest file.
Change it to:

<uses-sdk android:minSdkVersion="15" android:targetSdkVersion="15"/>

The targetSdkVersion should be an integer, but @string/app_name would be a string. I think this causing the error.

EDIT:
You have to add a default intent-filter in your manifiest file for the activity. Then only android can launch the activity. otherwise you will get the below error in your console window.

[2012-02-02 09:17:39 - Test] No Launcher activity found!
[2012-02-02 09:17:39 - Test] The launch will only sync the application package on the device!

Add the following to your <activity> tag.

<activity android:name="HelloAndroid" android:launchMode="standard" android:enabled="true">  
  <intent-filter>
    <action android:name="android.intent.action.MAIN" />
    <category android:name="android.intent.category.LAUNCHER" />
  </intent-filter>
</activity>