Fix fragment states (#170)

Change-Id: Iae9ee2791a3d2f408aef699028212c5bada7eb68

Author: samtstern

easypermissions/src/main/java/pub/devrel/easypermissions/RationaleDialogFragment.java

@@ -2,6 +2,7 @@
 
 import android.app.Dialog;
 import android.app.DialogFragment;
+import android.app.FragmentManager;
 import android.content.Context;
 import android.os.Build;
 import android.os.Bundle;
@@ -19,6 +20,7 @@ public class RationaleDialogFragment extends DialogFragment {
     public static final String TAG = "RationaleDialogFragment";
 
     private EasyPermissions.PermissionCallbacks mPermissionCallbacks;
+    private boolean mStateSaved = false;
 
     public static RationaleDialogFragment newInstance(
             @StringRes int positiveButton, @StringRes int negativeButton,
@@ -47,6 +49,31 @@ && getParentFragment() instanceof EasyPermissions.PermissionCallbacks) {
         }
     }
 
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        mStateSaved = true;
+        super.onSaveInstanceState(outState);
+    }
+
+    /**
+     * Version of {@link #show(FragmentManager, String)} that no-ops when an IllegalStateException
+     * would otherwise occur.
+     */
+    public void showAllowingStateLoss(FragmentManager manager, String tag) {
+        // API 26 added this convenient method
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            if (manager.isStateSaved()) {
+                return;
+            }
+        }
+
+        if (mStateSaved) {
+            return;
+        }
+
+        show(manager, tag);
+    }
+
     @Override
     public void onDetach() {
         super.onDetach();

easypermissions/src/main/java/pub/devrel/easypermissions/RationaleDialogFragmentCompat.java

@@ -6,6 +6,7 @@
 import android.support.annotation.NonNull;
 import android.support.annotation.RestrictTo;
 import android.support.annotation.StringRes;
+import android.support.v4.app.FragmentManager;
 import android.support.v7.app.AppCompatDialogFragment;
 
 /**
@@ -34,6 +35,18 @@ public static RationaleDialogFragmentCompat newInstance(
         return dialogFragment;
     }
 
+    /**
+     * Version of {@link #show(FragmentManager, String)} that no-ops when an IllegalStateException
+     * would otherwise occur.
+     */
+    public void showAllowingStateLoss(FragmentManager manager, String tag) {
+        if (manager.isStateSaved()) {
+            return;
+        }
+
+        show(manager, tag);
+    }
+
     @Override
     public void onAttach(Context context) {
         super.onAttach(context);

easypermissions/src/main/java/pub/devrel/easypermissions/helper/BaseFrameworkPermissionsHelper.java

@@ -24,6 +24,6 @@ public void showRequestPermissionRationale(@NonNull String rationale,
                                                @NonNull String... perms) {
         RationaleDialogFragment
                 .newInstance(positiveButton, negativeButton, rationale, requestCode, perms)
-                .show(getFragmentManager(), RationaleDialogFragment.TAG);
+                .showAllowingStateLoss(getFragmentManager(), RationaleDialogFragment.TAG);
     }
 }

easypermissions/src/main/java/pub/devrel/easypermissions/helper/BaseSupportPermissionsHelper.java

@@ -24,6 +24,6 @@ public void showRequestPermissionRationale(@NonNull String rationale,
                                                @NonNull String... perms) {
         RationaleDialogFragmentCompat
                 .newInstance(positiveButton, negativeButton, rationale, requestCode, perms)
-                .show(getSupportFragmentManager(), RationaleDialogFragmentCompat.TAG);
+                .showAllowingStateLoss(getSupportFragmentManager(), RationaleDialogFragmentCompat.TAG);
     }
 }