ActivityCompat.requestPermissions not showing dialog box
<pre><code>if (ContextCompat.checkSelfPermission(RegisterActivity.this,      Manifest.permission.READ_PHONE_STATE) == PackageManager.PERMISSION_DENIED){
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.READ_PHONE_STATE}, REQUEST_READ_PHONE_STATE_PERMISSION);
</code></pre>

<p>i'm trying to use this function on nexus 5 api 23 and its just not showing me the dialog box like its supposed to do, it's just not doing anything.
what could cause the problem? (this code is in the java activity)
i tried changing my minimum api to 23 and use the requestPermissions() without the ActivityCompat but still not working.</p>

<pre><code>apply plugin: 'com.android.application'

android {
compileSdkVersion 23
buildToolsVersion "23.0.2"

defaultConfig {
    applicationId "com.example.idanayzen.photomap"
    minSdkVersion 23
    targetSdkVersion 23
    versionCode 1
    versionName "1.0"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
}

dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:23.1.1'
compile 'com.google.android.gms:play-services:8.4.0'
compile 'com.android.support:design:23.1.1'
}
</code></pre>

<p>and the Manifest:</p>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.idanayzen.photomap"&gt;

&lt;uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /&gt;
&lt;uses-permission android:name="android.permission.READ_PHONE_STATE" /&gt;
&lt;uses-permission android:name="android.permission.READ_SMS" /&gt;

&lt;application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"&gt;


    &lt;meta-data
        android:name="com.google.android.geo.API_KEY"
        android:value="@string/google_maps_key" /&gt;

    &lt;activity
        android:name=".MapsActivity"
        android:label="@string/title_activity_maps" /&gt;
    &lt;activity android:name=".RegisterActivity"&gt;
        &lt;intent-filter&gt;
            &lt;action android:name="android.intent.action.MAIN" /&gt;

            &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
        &lt;/intent-filter&gt;
    &lt;/activity&gt;
    &lt;activity android:name=".WrongPhoneNum"&gt;&lt;/activity&gt;
&lt;/application&gt;

&lt;/manifest&gt;
</code></pre>