Develop Reference

Make Broadcast Receiver Alive when app is killed

I have created Broadcast Receiver for detect incoming call. It works fine when app is in foreground but it stopped working after kill app.
So i used Work Manager for achieve but it also wont work. I am not sure if i implemented Work Manager properly.
Please help me to make Broadcast Receiver alive when app is killed also suggest me right way if i made any mistake for get the result.
PhoneStateBroadcastReceiver.java
public class PhoneStateBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
TelephonyManager telephonyManager = (TelephonyManager) context.getSystemService(Context.TELEPHONY_SERVICE);
telephonyManager.listen(new PhoneStateListener() {
#Override
public void onCallStateChanged(int state, String phoneNumber) {
super.onCallStateChanged(state, phoneNumber);
try {
if (state == TelephonyManager.CALL_STATE_RINGING) {
Log.e("phoneNumber", phoneNumber);
}
} catch (Exception e) {
e.printStackTrace();
}
}
}, PhoneStateListener.LISTEN_CALL_STATE);
}
}
PhoneStateWorkManager.java
public class PhoneStateWorkManager extends Worker {
PhoneStateBroadcastReceiver phoneStateBroadcastReceiver;
public PhoneStateWorkManager(#NonNull Context context, #NonNull WorkerParameters workerParams) {
super(context, workerParams);
}
#NonNull
#Override
public Result doWork() {
if (phoneStateBroadcastReceiver == null) {
phoneStateBroadcastReceiver = new PhoneStateBroadcastReceiver();
}
IntentFilter filter = new IntentFilter(TelephonyManager.ACTION_PHONE_STATE_CHANGED);
getApplicationContext().registerReceiver(phoneStateBroadcastReceiver, filter);
return Result.success();
}
}
MainActivity.java
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addAutoStartup();
Constraints constraints = new Constraints
.Builder()
.setRequiredNetworkType(NetworkType.NOT_REQUIRED)
.build();
WorkRequest phoneStateRequest = new OneTimeWorkRequest
.Builder(PhoneStateWorkManager.class)
.setConstraints(constraints)
.build();
WorkManager.getInstance(MainActivity.this).enqueue(phoneStateRequest);
}
private void addAutoStartup() {
try {
Intent intent = new Intent();
String manufacturer = android.os.Build.MANUFACTURER;
if ("xiaomi".equalsIgnoreCase(manufacturer)) {
intent.setComponent(new ComponentName("com.miui.securitycenter", "com.miui.permcenter.autostart.AutoStartManagementActivity"));
} else if ("oppo".equalsIgnoreCase(manufacturer)) {
intent.setComponent(new ComponentName("com.coloros.safecenter", "com.coloros.safecenter.permission.startup.StartupAppListActivity"));
} else if ("vivo".equalsIgnoreCase(manufacturer)) {
intent.setComponent(new ComponentName("com.vivo.permissionmanager", "com.vivo.permissionmanager.activity.BgStartUpManagerActivity"));
} else if ("Letv".equalsIgnoreCase(manufacturer)) {
intent.setComponent(new ComponentName("com.letv.android.letvsafe", "com.letv.android.letvsafe.AutobootManageActivity"));
} else if ("Honor".equalsIgnoreCase(manufacturer)) {
intent.setComponent(new ComponentName("com.huawei.systemmanager", "com.huawei.systemmanager.optimize.process.ProtectActivity"));
}
List<ResolveInfo> list = getPackageManager().queryIntentActivities(intent, PackageManager.MATCH_DEFAULT_ONLY);
if (list.size() > 0) {
startActivity(intent);
}
} catch (Exception e) {
Log.e("exc", String.valueOf(e));
}
}
}

There are two ways to get callbacks when the phone state changes: PhoneStateListener and a BroadcastReceiver that listens to android.intent.action.PHONE_STATE.
I would recommend not using PhoneStateListener at all, and go with the BroadcastReceiver approach only, which can be setup via AndroidManifest which allows it to be called even when the app is not currently active.
See this tutorial: https://medium.com/#saishaddai/how-to-know-when-a-device-is-ringing-in-android-57e516d0ab42
Please note, that when an app is killed via "FORCE CLOSE" by the user, all the app's broadcast receiver are immediately put on pause, and the system prevents them from receiving future broadcasts until the user manually reopens that app.
see here
So as long as the user doesn't FORCE CLOSE your app, you should be able to receive phone state changes.

How to get MIUI Security app auto start permission programmatically?

I am not getting BOOT_COMPLETE broadcast in my Xiaomi Redmi 2 Prime mobile.
My BroadcastReciever is ---
public class OnBootReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// Setting singleAlarm
SingleAlarmHandler.getInstance().setAlarm(context);
try {
// Sending System Setting broadcast
String offDate = SharedPrefrencesHandler.getInstance(context).readString(SharedPrefrencesConstants.SWITCH_OFF_DATE);
int type = SystemSettingsType.PHONE_SWITCH_ON_OFF.getNumericType();
if (offDate == null)
offDate = "";
SystemSettingsHandler.getSystemSettingsHandler().makeSystemSettingsCall(context, type, offDate);
SharedPrefrencesHandler.getInstance(context).removePrefrence(SharedPrefrencesConstants.SWITCH_OFF_DATE);
} catch (Exception e) {
Log.e(ChaseForceApplication.TAG, e.getMessage());
}
}
}
and manifest:
<receiver
android:name=".broadcastlisteners.OnBootReceiver"
android:enabled="true"
android:exported="true">
<intent-filter>
<action android:name="android.intent.action.BOOT_COMPLETED" />
</intent-filter>
</receiver>
with permission:
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
Now I am not getting BOOT COMPLETE broadcast in my Xiaomi Redmi 2 Prime mobile as alarm is not set. But in other android mobiles it is working correctly.
I searched and found that it is problem in MIUI firmware. In such mobile they provide an in built security app and until you allow auto start permission in that Security app, you are unable to get broad cast (any notification).
And as soon as you check that permission in that app you start to get the broadcast.
Now my question is:
How to get MIUI Security app auto start permission( Phones like Redmi) programmatically?

this question already has answer in two Stack Overflow threads:
thread #1 https://stackoverflow.com/a/40932178/1537413
String xiaomi = "Xiaomi";
final String CALC_PACKAGE_NAME = "com.miui.securitycenter";
final String CALC_PACKAGE_ACITIVITY = "com.miui.permcenter.autostart.AutoStartManagementActivity";
if (deviceManufacturer.equalsIgnoreCase(xiaomi)) {
DisplayUtils.showDialog(activity, "Ask for permission", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
try {
Intent intent = new Intent();
intent.setComponent(new ComponentName(CALC_PACKAGE_NAME, CALC_PACKAGE_ACITIVITY));
activity.startActivity(intent);
} catch (ActivityNotFoundException e) {
Logger.e(TAG, "Failed to launch AutoStart Screen ", e);
} catch (Exception e) {
Logger.e(TAG, "Failed to launch AutoStart Screen ", e);
}
}
}, new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
}
thread #2 https://stackoverflow.com/a/41696993/1537413
String manufacturer = "xiaomi";
if(manufacturer.equalsIgnoreCase(android.os.Build.MANUFACTURER)) {
//this will open auto start screen where user can enable permission for your app
Intent intent = new Intent();
intent.setComponent(new ComponentName("com.miui.securitycenter", "com.miui.permcenter.autostart.AutoStartManagementActivity"));
startActivity(intent);
}
and for similar problem on huawei devices:
https://stackoverflow.com/a/35220476/1537413
private void ifHuaweiAlert() {
final SharedPreferences settings = getSharedPreferences("ProtectedApps", MODE_PRIVATE);
final String saveIfSkip = "skipProtectedAppsMessage";
boolean skipMessage = settings.getBoolean(saveIfSkip, false);
if (!skipMessage) {
final SharedPreferences.Editor editor = settings.edit();
Intent intent = new Intent();
intent.setClassName("com.huawei.systemmanager", "com.huawei.systemmanager.optimize.process.ProtectActivity");
if (isCallable(intent)) {
final AppCompatCheckBox dontShowAgain = new AppCompatCheckBox(this);
dontShowAgain.setText("Do not show again");
dontShowAgain.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
editor.putBoolean(saveIfSkip, isChecked);
editor.apply();
}
});
new AlertDialog.Builder(this)
.setIcon(android.R.drawable.ic_dialog_alert)
.setTitle("Huawei Protected Apps")
.setMessage(String.format("%s requires to be enabled in 'Protected Apps' to function properly.%n", getString(R.string.app_name)))
.setView(dontShowAgain)
.setPositiveButton("Protected Apps", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
huaweiProtectedApps();
}
})
.setNegativeButton(android.R.string.cancel, null)
.show();
} else {
editor.putBoolean(saveIfSkip, true);
editor.apply();
}
}
}
private boolean isCallable(Intent intent) {
List<ResolveInfo> list = getPackageManager().queryIntentActivities(intent,
PackageManager.MATCH_DEFAULT_ONLY);
return list.size() > 0;
}
private void huaweiProtectedApps() {
try {
String cmd = "am start -n com.huawei.systemmanager/.optimize.process.ProtectActivity";
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
cmd += " --user " + getUserSerial();
}
Runtime.getRuntime().exec(cmd);
} catch (IOException ignored) {
}
}
private String getUserSerial() {
//noinspection ResourceType
Object userManager = getSystemService("user");
if (null == userManager) return "";
try {
Method myUserHandleMethod = android.os.Process.class.getMethod("myUserHandle", (Class<?>[]) null);
Object myUserHandle = myUserHandleMethod.invoke(android.os.Process.class, (Object[]) null);
Method getSerialNumberForUser = userManager.getClass().getMethod("getSerialNumberForUser", myUserHandle.getClass());
Long userSerial = (Long) getSerialNumberForUser.invoke(userManager, myUserHandle);
if (userSerial != null) {
return String.valueOf(userSerial);
} else {
return "";
}
} catch (NoSuchMethodException | IllegalArgumentException | InvocationTargetException | IllegalAccessException ignored) {
}
return "";
}

You need to give permissions in the in build security application for xiaomi.
1. open the security app
2. go to permissions
3. go to auto start
4. enable the applications that you want to keep running in the background!
This worked for me..!

Android root activity sometimes started spontaneously without any user actions

I have a strange issue which I cannot explain. In the manifest file the launch activity of my app is defined as follows:
<activity
android:name="com.xxx.xxx.xxx.StartupActivity"
android:label="#string/app_name"
android:theme="#android:style/Theme.Light.NoTitleBar"
android:screenOrientation="sensorPortrait" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
In the StartUpActivity the following check is performed:
protected void startIntent() {
Intent intent;
if (checkCurrentProfile()) {
Notifier.showHttpToast(R.string.toastLoggedIn);
//try to update the device token in the database
Request.updateDeviceToken();
intent = new Intent(this, GameListActivity.class);
} else {
intent = new Intent(this, RegisterActivity.class);
}
startActivity(intent);
finish();
}
So if the user has a valid account the GameListActivity is shown as root activity:
<activity
android:name="com.xxx.xxx.xxx.xxx.GameListActivity"
android:label="#string/app_name"
android:theme="#style/MyTheme"
android:screenOrientation="sensorPortrait" >
</activity>
The issue now is the following: sometimes the system brings the root activity to the front spontaneously without any user actions. It only occurs sometimes, but I can't figure out the cause. Can anyone help me out here?
The StartUpActivity looks like this:
public class StartupActivity extends StartupCoreActivity implements OnRegisterGCMListener {
private IabHelper mHelper;
private IabHelper.QueryInventoryFinishedListener mQueryInventoryFinishedListener;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
registerOnRegisterGCMListener(this);
if (!registerGCMneeded()) {
initInAppBilling();
}
}
#Override
public void registerGCMfinished() {
initInAppBilling();
}
private void initInAppBilling() {
boolean hasPremium = Prefs.getBoolValue(getResources().getString(R.string.pref_key_upgrade_premium), false);
if (hasPremium) {
//unlocking contents not needed
startIntent();
} else {
Prefs.storeValue(getResources().getString(R.string.pref_key_upgrade_premium), false);
mHelper = new IabHelper(this, C.Billing.BILLING_KEY);
mHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
public void onIabSetupFinished(IabResult result) {
if (result.isSuccess()) {
queryInventory();
} else {
startIntent();
}
}
});
}
}
private void queryInventory() {
String[] products = {C.Billing.ITEM_SKU};
mQueryInventoryFinishedListener = new IabHelper.QueryInventoryFinishedListener() {
#Override
public void onQueryInventoryFinished(IabResult result, Inventory inv) {
if (result.isSuccess()) {
checkPremiumVersion(inv);
} else {
startIntent();
}
}
};
mHelper.queryInventoryAsync(true, Arrays.asList(products), mQueryInventoryFinishedListener);
}
private void checkPremiumVersion(Inventory inv) {
if (inv.hasPurchase(C.Billing.ITEM_SKU)) {
Request.updPremiumVersion();
Prefs.storeValue(getResources().getString(R.string.pref_key_upgrade_premium), true);
Notifier.showHttpToast(R.string.toastPremiumContentsUnlocked);
}
startIntent();
}
}
And the StartupCoreActivity looks like this:
public class StartupCoreActivity extends Activity {
private final static int PLAY_SERVICES_RESOLUTION_REQUEST = xxxx;
GoogleCloudMessaging mGcm;
Context mContext;
String mRegId;
/**
* Substitute you own sender ID here. This is the project number you got
* from the API Console, as described in "Getting Started."
*/
String SENDER_ID = "xxxxxxxxxx";
private OnRegisterGCMListener mOnRegisterGCMListener = null;
public void registerOnRegisterGCMListener(OnRegisterGCMListener listener) {
mOnRegisterGCMListener = listener;
}
protected boolean registerGCMneeded() {
mContext = getApplicationContext();
// Check device for Play Services APK.
if (checkPlayServices()) {
// If this check succeeds, proceed with normal processing.
// Otherwise, prompt user to get valid Play Services APK.
mGcm = GoogleCloudMessaging.getInstance(this);
mRegId = getRegistrationId(mContext);
if (mRegId.isEmpty()) {
registerInBackground();
return true;
} else {
// note we never called setContentView()
return false;
}
}
return false;
}
protected void startIntent() {
Intent intent;
if (checkCurrentProfile()) {
Notifier.showHttpToast(R.string.toastLoggedIn);
//try to update the device token in the database
Request.updateDeviceToken();
intent = new Intent(this, GameListActivity.class);
} else {
intent = new Intent(this, RegisterActivity.class);
}
startActivity(intent);
finish();
}
private boolean checkCurrentProfile() {
KUPlayer me = G.getMySelf();
if (me.getPlayerId() <= 0) {
//database was not present yet and has been created
//or database was present, but profile cannot be read anymore
// make sure Login screen appears ONLY if PlayerID cannot be retrieved anymore
if (G.getPlayerID() <=0) {
Prefs.storeValue(Prefs.PREF_KEY_PWD_SAVED, false);
return false;
}
}
return true;
}
// You need to do the Play Services APK check here too.
#Override
protected void onResume() {
super.onResume();
checkPlayServices();
}
/**
* Check the device to make sure it has the Google Play Services APK. If
* it doesn't, display a dialog that allows users to download the APK from
* the Google Play Store or enable it in the device's system settings.
*/
private boolean checkPlayServices() {
int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
if (resultCode != ConnectionResult.SUCCESS) {
if (GooglePlayServicesUtil.isUserRecoverableError(resultCode)) {
GooglePlayServicesUtil.getErrorDialog(resultCode, this,
PLAY_SERVICES_RESOLUTION_REQUEST).show();
} else {
finish();
}
return false;
}
return true;
}
/**
* Registers the application with mGcm servers asynchronously.
* <p>
* Stores the registration ID and the app versionCode in the application's
* shared preferences.
*/
private void registerInBackground() {
new AsyncTask<Void, Void, String>() {
#Override
protected String doInBackground(Void... params) {
String msg = "";
try {
if (mGcm == null) {
mGcm = GoogleCloudMessaging.getInstance(mContext);
}
mRegId = mGcm.register(SENDER_ID);
msg = "Device registered, registration ID=" + mRegId;
// Persist the mRegId - no need to register again.
storeRegistrationId(mContext, mRegId);
} catch (IOException ex) {
msg = "Error :" + ex.getMessage();
// If there is an error, don't just keep trying to register.
// Require the user to click a button again, or perform
// exponential back-off.
}
return msg;
}
#Override
protected void onPostExecute(String msg) {
// note we never called setContentView()
if (mOnRegisterGCMListener != null) {
mOnRegisterGCMListener.registerGCMfinished();
}
}
}.execute(null, null, null);
}
/**
* #return Application's version code from the {#code PackageManager}.
*/
private static int getAppVersionCode(Context context) {
try {
PackageInfo packageInfo = context.getPackageManager()
.getPackageInfo(context.getPackageName(), 0);
return packageInfo.versionCode;
} catch (NameNotFoundException e) {
// should never happen
throw new RuntimeException("Could not get package name: " + e);
}
}
private static String getAppVersionName(Context context) {
try {
PackageInfo packageInfo = context.getPackageManager()
.getPackageInfo(context.getPackageName(), 0);
return packageInfo.versionName;
} catch (NameNotFoundException e) {
// should never happen
throw new RuntimeException("Could not get package name: " + e);
}
}
/**
* Stores the registration ID and the app versionCode in the application's
* {#code SharedPreferences}.
*
* #param mContext application's mContext.
* #param mRegId registration ID
*/
private void storeRegistrationId(Context context, String regId) {
Prefs.storeValue(Prefs.PREF_KEY_DEVICE_TOKEN, regId);
Prefs.storeValue(Prefs.PREF_KEY_APP_VERSION_CODE, getAppVersionCode(context));
Prefs.storeValue(Prefs.PREF_KEY_APP_VERSION_NAME, getAppVersionName(context));
AppRate.resetAfterUpdate();
}
/**
* Gets the current registration ID for application on mGcm service, if there is one.
* <p>
* If result is empty, the app needs to register.
*
* #return registration ID, or empty string if there is no existing
* registration ID.
*/
private String getRegistrationId(Context context) {
String registrationId = Prefs.getStringValue(Prefs.PREF_KEY_DEVICE_TOKEN);
if (registrationId.isEmpty()) {
return "";
}
// Check if app was updated; if so, it must clear the registration ID
// since the existing mRegId is not guaranteed to work with the new
// app version.
int registeredVersion = Prefs.getIntValue(Prefs.PREF_KEY_APP_VERSION_CODE);
int currentVersion = getAppVersionCode(context);
if (registeredVersion != currentVersion) {
return "";
}
return registrationId;
}
}

I guess it has to do with the following known Android bug:
How to prevent multiple instances of an activity when it is launched with different intents
And as suggested put the following code in the onCreate method of the rootActivity:
// Possible work around for market launches. See http://code.google.com/p/android/issues/detail?id=2373
// for more details. Essentially, the market launches the main activity on top of other activities.
// we never want this to happen. Instead, we check if we are the root and if not, we finish.
if (!isTaskRoot()) {
final Intent intent = getIntent();
final String intentAction = intent.getAction();
if (intent.hasCategory(Intent.CATEGORY_LAUNCHER) && intentAction != null && intentAction.equals(Intent.ACTION_MAIN)) {
finish();
return;
}
}
I tested it and when you start your app from Google Play store in stead of launch screen, then indeed finish() is called from above code.

password protected uninstall in android 4+ versions [programmatically]

i want my app to have a password protected uninstall ... (like app lock)
im using folling code it works on Android 2.3 but not on Android 4+ versions
MANIFEST FILE
<receiver android:name="fyp.invisibleink.UninstallIntentReceiver" >
<intent-filter android:priority="0" >
<action android:name="android.intent.action.QUERY_PACKAGE_RESTART" />
<data android:scheme="package" />
</intent-filter>
</receiver>
Uninstalling Activity code
ublic class Uninstalling extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_uninstalling);
// listener
Button settingsBtn = (Button) findViewById(R.id.btnu);
settingsBtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final EditText e1 = (EditText) findViewById(R.id.etpass);
final String pass = e1.getText().toString();
SharedPreferences cupSetting = getSharedPreferences(
"cuppassword", Context.MODE_PRIVATE);
String mypass = cupSetting.getString("pass", "");
if (pass.equals(mypass)) {
Toast.makeText(getApplicationContext(),
"password is correct!", Toast.LENGTH_LONG).show();
Toast.makeText(getApplicationContext(),
"press OK to uninstall!", Toast.LENGTH_LONG).show();
finish();
} else {
Toast.makeText(getApplicationContext(),
"Access Denied! try again", Toast.LENGTH_LONG)
.show();
e1.setText("");
}
}
});
}
UninstallReceveier
public class UninstallIntentReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// TODO Auto-generated method stub
// fetching package names from extras
String[] packageNames = intent
.getStringArrayExtra("android.intent.extra.PACKAGES");
if (packageNames != null) {
for (String packageName : packageNames) {
if (packageName != null
&& packageName.equals("com.example.invisibleink")) {
// User has selected our application under the Manage Apps
// settings
// now initiating background thread to watch for activity
new ListenActivities(context).start();
}
}
}
}
// ///////////////////////////////
class ListenActivities extends Thread {
boolean exit = false;
ActivityManager am = null;
Context context = null;
public ListenActivities(Context con) {
context = con;
am = (ActivityManager) context
.getSystemService(Context.ACTIVITY_SERVICE);
}
#Override
public void run() {
Looper.prepare();
while (!exit) {
// get the info from the currently running task
List<ActivityManager.RunningTaskInfo> taskInfo = am
.getRunningTasks(MAX_PRIORITY);
String activityName = taskInfo.get(0).topActivity
.getClassName();
Log.d("topActivity", "CURRENT Activity ::" + activityName);
if (activityName
.equals("com.android.packageinstaller.UninstallerActivity")) {
// User has clicked on the Uninstall button under the Manage
// Apps settings
Intent intent = new Intent(context, Uninstalling.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent);
exit = true;
// do whatever pre-uninstallation task you want to perform
// here
// show dialogue or start another activity or database
// operations etc..etc..
// context.startActivity(new Intent(context,
// MyPreUninstallationMsgActivity.class).setFlags(Intent.FLAG_ACTIVITY_NEW_TASK));
} else if (activityName
.equals("com.android.settings.ManageApplications")) {
// back button was pressed and the user has been taken back
// to Manage Applications window
// we should close the activity monitoring now
exit = true;
}
}
Looper.loop();
}
}
}
Permissioms
<uses-permission android:name="android.permission.GET_TASKS" />

I am not positive, so please correct me if I'm wrong but this might have been removed as a security feature. A malicious app might be able to create a password and avoid the app from being removed creating further damage on the device. Like I said, I could be wrong but this is a guess that seems legit. I noticed that 4+ did a couple things for security because of a lot of malicious stuff and exploits happening within 3rd party apps.

Android: change default Home Application

for some specific requirement
I am required to change Android Default Home application
with my customized Home application ( a setting inside my app that will toggle default home = my application or previous home)
I don't want the user to travel android settings that are very complicated.
Can any one help me out like where it registers launcher.apk for default
home application or how to change that
The only thing I could find was that old question: How to change default Android's Desktop application?
but no answers at all.
I have seen HomeSwitcher in the Market that do the trick, but no answer for the developer that might certainly be busy.
EDIT
I found this on the web http://www.mail-archive.com/android-developers#googlegroups.com/msg74167.html
But I got the same issue:
this is my code:
private void makePreferred() {
PackageManager pm = getPackageManager();
IntentFilter f = new IntentFilter("android.intent.action.MAIN");
f.addCategory("android.intent.category.HOME");
f.addCategory("android.intent.category.DEFAULT");
ComponentName cn = new ComponentName("com.example.android.home", "com.example.android.home.Home");
pm.addPreferredActivity(f, IntentFilter.MATCH_CATEGORY_EMPTY, null, cn);
I have the android.permission.SET_PREFERRED_APPLICATIONS set in the
manifest. After executing the code above, the logs claim things have
been added like expected (same logs as when I tick off "Make default"
from IntentResolver's list). However, when I proceed by clicking home,
the list still shows up and the logs say:
INFO/PackageManager(52): Result set changed, dropping preferred
activity for Intent { act=android.intent.action.MAIN cat=
[android.intent.category.HOME] flg=0x10200000 } type null
So it seems the resolver deletes the default entry. Am I doing
something wrong, or is this a security measure? What are the ideas
behind this?

I did an extensive research on that and starting from 2.2 there is no way to do that. The only way is using some hacking that toddler lock app does but this app put samsung phones recently in the infinite loop, so it is a risky approach.
if you look at the froyo source code here of packagemanager class, you will see this small condition in the addPreferredActivity method:
if (getUidTargetSdkVersionLockedLP(Binder.getCallingUid())
< Build.VERSION_CODES.FROYO) {
Slog.w(TAG, "Ignoring addPreferredActivity() from uid"
+ Binder.getCallingUid());
return;
}
HomeSwitcher does not work properly on 2.2 since it uses this very method and developer made a comment on app page "Froyo(2.2) is not supported
due to the API change"

"Result set changed" means that the set of packages matching that intent has changed from the set you specified when you created the default - - so the default is no longer valid. Your list of components (which you are currently setting to null) needs to contain all homescreen apps present on device, not just yours.
Here's example code that I have tested (using adb shell am start http://www.google.co.uk/ ) and used to set the default browser. XXX represents a customer name that I had to black out.
Note that in order to call addPreferredActivity you must have compiled against a minimum-sdk version of 8 (2.2) and you must have specified the SET_PREFERRED_APPLICATIONS permission. That permission is protection level 2, so you need to be signed with the same certificate as PackageManager.
IntentFilter filter = new IntentFilter();
filter.addAction("android.intent.action.VIEW");
filter.addCategory("android.intent.category.DEFAULT");
filter.addDataScheme("http");
Context context = getApplicationContext();
ComponentName component = new ComponentName("com.opera.mini.XXX", "com.opera.mini.XXX.CustomerBrowser");
ComponentName[] components = new ComponentName[] {new ComponentName("com.android.browser", "com.android.browser.BrowserActivity"),
component};
pm.addPreferredActivity(filter, IntentFilter.MATCH_CATEGORY_SCHEME, components, component);
ETA - if you marked this response down, could you let me know why. The code I posted above is tested and working...

startActivity(new Intent(Settings.ACTION_HOME_SETTINGS));

This code works on my ICS device: I use a service that is sensible to some call, one of them is called SET_PREFERRED_LAUNCHER, the put in a bundle your new default Launcher package (PREFERRED_PACKAGE_KEY) and it's activity (PREFERRED_ACTIVITY_KEY)
Method installPackageMethod = null;
Method deletePackageMethod = null;
Method setPreferredActivityMethod = null;
Method replacePreferredActivityMethod = null;
Object pm = null;
#Override
public void onCreate() {
super.onCreate();
if (pm == null)
pm = getPackageManager();
try {
if (setPreferredActivityMethod == null)
setPreferredActivityMethod = pm.getClass().getMethod(
"addPreferredActivity", IntentFilter.class, int.class,
ComponentName[].class, ComponentName.class);
} catch (NoSuchMethodException e) {
e.printStackTrace();
}
}
private final class ServiceHandler extends Handler {
private Context context;
public ServiceHandler(Looper looper, Context ctx) {
super(looper);
context = ctx;
}
#Override
public void handleMessage(Message msg) {
Intent intent = (Intent) msg.getData().getParcelable(
UPDATER_SERVICE_ACTION);
int request = intent.getIntExtra(
REQUEST_KEY,
REQUEST_UNKNOWN);
Bundle bundle = intent.getExtras();
switch (request) {
case INSTALL_APPLICATION: {
if (bundle != null) {
String appPath = bundle
.getString(APP_PATH_KEY);
if (appPath != null) {
LogUtil.e(TAG, "try to install " + appPath);
try {
am.installPackage(appPath);
} catch (Exception e) {
e.printStackTrace();
}
LogUtil.e(TAG, "install of " + appPath + " done");
}
}
break;
}
case UNISTALL_PACKAGE: {
if (bundle != null) {
String packagename = bundle
.getString(PACKAGE_NAME_KEY);
if (packagename != null) {
LogUtil.e(TAG, "unistall " + packagename);
try {
deletePackageMethod
.invoke(pm, packagename, null, 0);
} catch (Exception e) {
e.printStackTrace();
}
}
}
break;
}
case SET_PREFERRED_LAUNCHER: {
if (bundle != null) {
String package_name = bundle
.getString(PREFERRED_PACKAGE_KEY);
if (package_name == null) {
LogUtil.e(TAG,
"WARNING: setDefaultActivity cannot continue, package is NULL");
return;
}
String activity_name = bundle
.getString(PREFERRED_ACTIVITY_KEY);
if (activity_name == null) {
LogUtil.e(TAG,
"WARNING: setDefaultActivity cannot continue, activity is NULL");
return;
}
LogUtil.e(TAG, "setDefaultActivity activity="
+ activity_name + " package=" + package_name);
IntentFilter filter = new IntentFilter(
"android.intent.action.MAIN");
filter.addCategory("android.intent.category.HOME");
filter.addCategory("android.intent.category.DEFAULT");
ComponentName[] components = new ComponentName[] {
new ComponentName("com.android.launcher",
"com.android.launcher2.Launcher"),
new ComponentName(package_name, activity_name) };
ComponentName activity = new ComponentName(package_name,
activity_name);
try {
setPreferredActivityMethod.invoke(pm, filter,
IntentFilter.MATCH_CATEGORY_EMPTY, components,
activity);
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
}
}
Remember to add in your manifest file this permission:
<uses-permission android:name="android.permission.SET_PREFERRED_APPLICATIONS"/>
Usage:
public void setPreferredLauncher(String activity_name,String package_name)
{
Intent intent = new Intent(UPDATER_SERVICE_ACTION);
intent.putExtra(REQUEST_KEY, SET_PREFERRED_LAUNCHER);
intent.putExtra(PREFERRED_ACTIVITY_KEY, activity_name);
intent.putExtra(PREFERRED_PACKAGE_KEY, package_name);
context.startService(intent);
}
where:
public static final String _UPDATER_SERVICE_ACTION = "com.android.updaterservice.ACTION";
public static final String REQUEST_KEY = "com.android.updaterservice.REQUEST_KEY";
public static final String PACKAGE_NAME_KEY = "com.android.updaterservice.PACKAGE_NAME_KEY";
public static final String APP_PATH_KEY = "com.android.updaterservice.APP_PATH_KEY";
public static final String PREFERRED_ACTIVITY_KEY = "com.android.updaterservice.PREFERRED_ACTIVITY_KEY";
public static final String PREFERRED_PACKAGE_KEY = "com.android.updaterservice.PREFERRED_PACKAGE_KEY";
public static final String INSTALL_PACKAGE_RESULT = "com.android.updaterservice.INSTALL_PACKAGE_RESULT";
public static final String PACKAGE_NAME = "PACKAGE_NAME";
public static final String INSTALL_SUCCEEDED = "INSTALL_SUCCEEDED";
public static final int REQUEST_UNKNOWN = -1;
public static final int INSTALL_APPLICATION = 1;
public static final int UNISTALL_PACKAGE = 2;
public static final int SET_PREFERRED_LAUNCHER = 3;