Android: cosa scegliere per i valori del codice di richiesta?

Question

Metodi come ActivityCompat.requestPermissions richiedono che io passi loro un codice di richiesta che posso successivamente verificare in un callback (in questo caso onRequestPermissionsResult). C'è qualche sorta di best practice che dovrei passare nel codice di richiesta? Ho notato che se ho appena entro in un caso int a volte ottengo un errore come questo:

java.lang.IllegalArgumentException: Can only use lower 8 bits for requestCode 



10-25 16:47:43.652 8315-8315/? E/AndroidRuntime: FATAL EXCEPTION: main 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime: Process: my package, PID: 8315 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{mypackage.myactivity}: java.lang.IllegalArgumentException: Can only use lower 8 bits for requestCode 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2416) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread.-wrap11(ActivityThread.java) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.os.Handler.dispatchMessage(Handler.java:102) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.os.Looper.loop(Looper.java:148) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread.main(ActivityThread.java:5417) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Native Method) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime: Caused by: java.lang.IllegalArgumentException: Can only use lower 8 bits for requestCode 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.support.v4.app.FragmentActivity.validateRequestPermissionsRequestCode(FragmentActivity.java:799) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.support.v4.app.ActivityCompatApi23.requestPermissions(ActivityCompat23.java:29) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.support.v4.app.ActivityCompat.requestPermissions(ActivityCompat.java:316) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at mypackage.myactivity.checkReadPhoneState(PermissionsGatewayActivity.java:48) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at mypackage.myactivity.onCreate(PermissionsGatewayActivity.java:36) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.Activity.performCreate(Activity.java:6237) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1107) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2369) 
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)  
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread.-wrap11(ActivityThread.java)  
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)  
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.os.Handler.dispatchMessage(Handler.java:102)  
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.os.Looper.loop(Looper.java:148)  
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at android.app.ActivityThread.main(ActivityThread.java:5417)  
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at java.lang.reflect.Method.invoke(Native Method)  
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)  
10-25 16:47:43.652 8315-8315/? E/AndroidRuntime:  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)  

Answer 1

Documentare i risultati di riferimento futuro:

Di seguito sono riportati codice android.support.v4.app.FragmentActivity

/** 
* Modifies the standard behavior to allow results to be delivered to fragments. 
* This imposes a restriction that requestCode be <= 0xffff. 
*/ 
@Override 
public void startActivityForResult(Intent intent, int requestCode) { 
    if (requestCode != -1 && (requestCode&0xffff0000) != 0) { 
     throw new IllegalArgumentException("Can only use lower 16 bits for requestCode"); 
    } 
    super.startActivityForResult(intent, requestCode); 
} 

@Override 
public final void validateRequestPermissionsRequestCode(int requestCode) { 
    // We use 16 bits of the request code to encode the fragment id when 
    // requesting permissions from a fragment. Hence, requestPermissions() 
    // should validate the code against that but we cannot override it as 
    // we can not then call super and also the ActivityCompat would call 
    // back to this override. To handle this we use dependency inversion 
    // where we are the validator of request codes when requesting 
    // permissions in ActivityCompat. 
    if (!mRequestedPermissionsFromFragment 
      && requestCode != -1 && (requestCode & 0xffff0000) != 0) { 
     throw new IllegalArgumentException("Can only use lower 16 bits for requestCode"); 
    } 
} 

GAMMA
startActivityForResult() in FragmentActivity richiede l'requestCode essere di 16 bit, il che significa l'intervallo va da 0 a 65535 .

Inoltre, validateRequestPermissionsRequestCode in FragmentActivity richiede requestCode essere di 16 bit, il che significa l'intervallo va da 0 a 65535 .