Add permission request

app/src/main/java/com/hippo/util/PermissionRequester.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2015 Hippo Seven
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.hippo.util;
+
+import android.app.Activity;
+import android.content.DialogInterface;
+import android.content.pm.PackageManager;
+import android.support.v4.app.ActivityCompat;
+import android.support.v7.app.AlertDialog;
+
+public class PermissionRequester {
+
+    /**
+     * @return true for there no need to request, do your work it now.
+     * false for do in {@link android.support.v4.app.ActivityCompat.OnRequestPermissionsResultCallback#onRequestPermissionsResult(int, String[], int[])}
+     */
+    public static boolean request(final Activity activity, final String permission, String rationale, final int requestCode) {
+        if (!(activity instanceof ActivityCompat.OnRequestPermissionsResultCallback)) {
+            throw new IllegalStateException("The Activity must implement ActivityCompat.OnRequestPermissionsResultCallback");
+        }
+
+        if (ActivityCompat.checkSelfPermission(activity, permission)
+                == PackageManager.PERMISSION_GRANTED) {
+            return true;
+        }
+
+        if (ActivityCompat.shouldShowRequestPermissionRationale(activity, permission)) {
+            new AlertDialog.Builder(activity)
+                    .setMessage(rationale)
+                    .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
+                        @Override
+                        public void onClick(DialogInterface dialog, int which) {
+                            ActivityCompat.requestPermissions(activity,
+                                    new String[]{permission},
+                                    requestCode);
+                        }
+                    }).setNegativeButton(android.R.string.cancel, null);
+        } else {
+            ActivityCompat.requestPermissions(activity,
+                    new String[]{permission},
+                    requestCode);
+        }
+
+        return false;
+    }
+}