ActivityCompat.requestPermissions not showing dialog box

Question

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);

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.

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'
}

and the Manifest:

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

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
<uses-permission android:name="android.permission.READ_SMS" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">


    <meta-data
        android:name="com.google.android.geo.API_KEY"
        android:value="@string/google_maps_key" />

    <activity
        android:name=".MapsActivity"
        android:label="@string/title_activity_maps" />
    <activity android:name=".RegisterActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".WrongPhoneNum"></activity>
</application>

</manifest>

Answer 1

Here's an example of using requestPermissions():

First, define the permission (as you did in your post) in the manifest, otherwise, your request will automatically be denied:

<uses-permission android:name="android.permission.READ_PHONE_STATE" />

Next, define a value to handle the permission callback, in onRequestPermissionsResult():

private final int REQUEST_PERMISSION_PHONE_STATE=1;

Here's the code to call requestPermissions():

private void showPhoneStatePermission() {
    int permissionCheck = ContextCompat.checkSelfPermission(
            this, Manifest.permission.READ_PHONE_STATE);
    if (permissionCheck != PackageManager.PERMISSION_GRANTED) {
        if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.READ_PHONE_STATE)) {
            showExplanation("Permission Needed", "Rationale", Manifest.permission.READ_PHONE_STATE, REQUEST_PERMISSION_PHONE_STATE);
        } else {
            requestPermission(Manifest.permission.READ_PHONE_STATE, REQUEST_PERMISSION_PHONE_STATE);
        }
    } else {
        Toast.makeText(MainActivity.this, "Permission (already) Granted!", Toast.LENGTH_SHORT).show();
    }
}

First, you check if you already have permission (remember, even after being granted permission, the user can later revoke the permission in the App Settings.)

And finally, this is how you check if you received permission or not:

@Override
public void onRequestPermissionsResult(
        int requestCode,
        String permissions[],
        int[] grantResults) {
    switch (requestCode) {
        case REQUEST_PERMISSION_PHONE_STATE:
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                Toast.makeText(MainActivity.this, "Permission Granted!", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(MainActivity.this, "Permission Denied!", Toast.LENGTH_SHORT).show();
            }
    }
}

private void showExplanation(String title,
                             String message,
                             final String permission,
                             final int permissionRequestCode) {
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle(title)
            .setMessage(message)
            .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int id) {
                    requestPermission(permission, permissionRequestCode);
                }
            });
    builder.create().show();
}

private void requestPermission(String permissionName, int permissionRequestCode) {
    ActivityCompat.requestPermissions(this,
            new String[]{permissionName}, permissionRequestCode);
}