问题
I realise this question has been asked many times, but I am still unable to completely understand this concept. In my application, I am using a static utility class to keep common methods (like showing error dialogs)
Here is how my static class looks like:
public class GlobalMethods {
//To show error messages
public static final void showSimpleAlertDialog(final Activity activity, String message, final boolean shouldFinishActivity) {
if (!activity.isFinishing()) {
AlertDialog.Builder builder = new AlertDialog.Builder(activity, AlertDialog.THEME_HOLO_DARK);
builder.setCancelable(true).setMessage("\n" + message + "\n").setNeutralButton(activity.getResources().getString(R.string.label_ok), new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
dialog.cancel();
}
}).setOnCancelListener(new DialogInterface.OnCancelListener() {
@Override
public void onCancel(DialogInterface dialog) {
// TODO Auto-generated method stub
if (shouldFinishActivity)
activity.finish();
}
}).show();
}
}
//check for connectivity
public static final boolean isOnline(Context context) {
NetworkInfo networkInfo = ((ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE)).getActiveNetworkInfo();
return (networkInfo != null && networkInfo.isConnectedOrConnecting());
}
//for the 'HOME' button on every activity
public static final void goToDashboard(Activity activity) {
goToActivity(ActivityDashboard.class, activity);
}
}
In my main activity, I call this function like this
GlobalMethods.showSimpleAlertDialog(this, R.string.error_msg_failed_load, true);
Is this a good approach? Does this cause memory leaks? If yes, please guide me on the best practices on using utility classes
回答1:
No, it's a bad approach.
You better pass WeakReference<Activity>
to your methods, and implement methods like this:
public static final void showSimpleAlertDialog(final WeakReference<Activity> mReference, String message, final boolean shouldFinishActivity) {
Activity activity = mReference.get();
if (activity != null) {
//your code goes here
}
Further reading: http://android-developers.blogspot.ae/2009/01/avoiding-memory-leaks.html
来源:https://stackoverflow.com/questions/18865060/passing-reference-to-activity-to-utility-class-android