I would like to write an application that uses live wallpapers for insatnce. this feature is supported only in version 7 and up. Is it posiible, that the application checks the version of the android phone and depending on that runs different code (e.g. uses live wallpaper or static background.)
Do you have a code example for that? Does that require special permissions?
Assuming you're requiring Android 1.6 or newer:
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ECLAIR_MR1) {
...
}
Yes there is. Look at the Build class in Android. You can use it like so Build.VERSION.SDK_INT
public static final int ECLAIR_MR1 =7;
public static final int FROYO =8;
if(Build.VERSION.SDK_INT==FROYO){
Toast.makeText(getApplicationContext(), "Iam a FROYO-Phone", 1).show();
}else if(Build.VERSION.SDK_INT==ECLAIR_MR1){
Toast.makeText(getApplicationContext(), "Iam an ECLAIR-Phone", 1).show();
}
SDK_INT is not available on very early builds. So if your manifest has for instance:
android:minSdkVersion="1"
you can use something like this:
#TargetApi(Build.VERSION_CODES.DONUT)
static boolean getPreHoneyComb() {
try {
Build.VERSION.class.getField("SDK_INT");
}
catch (NoSuchFieldException e) {
return true;
}
return Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB;
}
Related
Is there any way I can support both deprecated and new API in the same method call for Android? I'm using the camera API which seems to be deprecated for the Lollipop version, so I tried to handle it like this:
if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.LOLLIPOP)
{
//Before Lollipop, use the Camera API since it still supported.
}
else
{
//Use the CameraManager
try
{
for (int i= 0; i < _camera.getCameraIdList().length; i++)
{
System.out.println("Camera= " + _camera.getCameraIdList()[i]);
}
}
catch (CameraAccessException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
}
But this does however just give me the error Call requires API level 21 (current min is 15): android.hardware.camera2.CameraManager#getCameraIdList
I tried SupressLint and TargetApi but that only made the device running an earlier (before Lollipop) Android version crash when creating an class instance of this type.
Thanks for any help!
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
//handler lollipop and higher
} else {
//earlier api calls
}
Simply having code in a class does not crash any Android 2.0+ device - code actually needs to run for it to crash. Check to make sure all of your Lollipop specific code is wrapped in version checks.
I want to check if a device has any cameras before trying to open a qr code reader.
I have the following code:
public boolean checkDeviceCompatibility() {
PackageManager pm = context.getPackageManager();
if (pm.hasSystemFeature(PackageManager.FEATURE_CAMERA_ANY)) {
if (pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
return true;
} else {
// use front camera
Toast.makeText(
context,
"This device does not have a back camera so it has automatically reverted to the front camera",
Toast.LENGTH_SHORT).show();
return true;
}
} else {
util.displayErrorDialog(
context,
"This device does not have any cameras and therefore cannot make use of the QR Code feature.");
return false;
}
}
But now if I run this code in debug mode on my galaxy S3 with two cameras. the first if statement is returned false.
Why could this be?
FEATURE_CAMERA_ANY was added in Android 4.2. hasSystemFeature(PackageManager.FEATURE_CAMERA_ANY) should return false for any pre-4.2 device. If your S3 is still on 4.1, that would explain your problem.
To make it clear.
FEATURE_CAMERA_ANY was added to Android 4.2 ( API-17): Android - developers.
code:
public static boolean hasCamera(Context context) {
return context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_ANY);
}
Note that using this code will return false if device under version 4.2:
Then you should know that there is a bug with emulator when use FEATURE_CAMERA_ANY feature (with android 4.2 and above). see: Emulator does not honour Camera support flag
Thats why Im still using old way even its deprecated:
public static boolean hasCamera() {
return android.hardware.Camera.getNumberOfCameras() > 0;
}
I have some code that compiles successfully using ViewTreeObserver#removeOnGlobalLayoutListener(...) and when it runs, this method throws NoSuchMethodError. Why?
There are two methods in ViewTreeObserver with almost the same name.
removeOnGlobalLayoutListener(ViewTreeObserver.OnGlobalLayoutListener victim)
(on then global) is a method that was added in API 16. It replaces
removeGlobalOnLayoutListener(ViewTreeObserver.OnGlobalLayoutListener victim)
(global then on) which has existed since API 1, but which is now deprecated.
Both methods can appear present at compile-time (if you're building against Jellybean or higher) but the newer one will fail on pre-Jellybean devices.
This code thwarts the error:
try {
thing.removeOnGlobalLayoutListener(victim);
} catch (NoSuchMethodError x) {
thing.removeGlobalOnLayoutListener(victim);
}
So does this code:
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
thing.removeGlobalOnLayoutListener(victim);
} else {
thing.removeOnGlobalLayoutListener(victim);
}
I assume you are talking about removeOnGlobalLayoutListener from ViewTreeObserver class. This method was added in API level 16. My best guess is that you try to use it on a device running an old version of Android that's why it can't be found.
I have working code
public static void removeOnGlobalLayoutListener(View v, ViewTreeObserver.OnGlobalLayoutListener listener){
if (Build.VERSION.SDK_INT < 16) {
v.getViewTreeObserver().removeGlobalOnLayoutListener(listener);
} else {
v.getViewTreeObserver().removeOnGlobalLayoutListener(listener);
}
}
Im developing an app with the latest android version (4.2.1 API-Level 17) for tablets with multiuser capabilities.
I want to restrict certain features (like the access to the app preferences) to the owner of the tablet (that is the user who can add and remove other user accounts)
is there any way i can find out if the current user is the owner?
i read through the UserManager and UserHandle API docs but couldn't find a function that allows me to check for it.
have i missed something or is there another way to do that?
Similar but without reflection:
static boolean isAdminUser(Context context)
{
UserHandle uh = Process.myUserHandle();
UserManager um = (UserManager) context.getSystemService(Context.USER_SERVICE);
if(null != um)
{
long userSerialNumber = um.getSerialNumberForUser(uh);
Log.d(TAG, "userSerialNumber = " + userSerialNumber);
return 0 == userSerialNumber;
}
else
return false;
}
You can create an extension property in Kotlin to make it simpler:
val UserManager.isCurrentUserDeviceOwner: Boolean
get() = if (SDK_INT >= 23) isSystemUser
else if (SDK_INT >= 17) getSerialNumberForUser(Process.myUserHandle()) == 0L
else true
Then, using it is as simple as the following:
val userManager = context.getSystemService(Context.USER_SERVICE) as UserManager
if (userManager.isCurrentUserDeviceOwner) TODO() else TODO()
You can further reduce boilerplate by using global system services definitions that makes userManager and other Android System Services available anywhere in your Kotlin code, with code included in this library I made: https://github.com/LouisCAD/Splitties/tree/master/systemservices
After researching further i found out that the multiuser api is not functional yet, it cant really be used for anything. there is a hack though for checking if the user is the owner using reflections:
public boolean isCurrentUserOwner(Context context)
{
try
{
Method getUserHandle = UserManager.class.getMethod("getUserHandle");
int userHandle = (Integer) getUserHandle.invoke(context.getSystemService(Context.USER_SERVICE));
return userHandle == 0;
}
catch (Exception ex)
{
return false;
}
}
This works for me on the Nexus 7 and Nexus 10 with Android 4.2.1
Its very dirty. so i wouldnt recommend using it unless you are making an app thats device and version specific
So the code is following:
public static ActionBarHelper createInstance(Activity activity) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
return new ActionBarHelperICS(activity);
} else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
return new ActionBarHelperHoneycomb(activity);
} else {
return new ActionBarHelperBase(activity);
}
}
If my device is 2.3 (api 9) it shouldn't support Build.VERSION_CODES.ICE_CREAM_SANDWICH but yet it runs, why is that? If it had been a method I called it would have crashed. Is it because it is a public static final int and therefor added from to my code? Please give some general detail and not just a yes/no answer :)
As Stefan pointed out, the api level used to compile the code determines the constants visible at compile time. For my case this doesn't give any problems as I just compare simple values. This only give problems if you use a set method that uses different constants and you happent to use a constant that wasn't possible to handle for your api version.