Android Permission

AndroidManifest.xml

    <!-- Storage -->
    <uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

    <!-- Camera -->
    <uses-permission android:name="android.permission.CAMERA" />
    <!--<uses-permission android:name="android.permission.FLASHLIGHT" />-->

    <uses-feature android:name="android.hardware.camera" android:required="true"/>
    <uses-feature android:name="android.hardware.camera.autofocus"  android:required="false"/>
    <uses-feature android:name="android.hardware.camera.front" android:required="true" />

MainActivity.java

    Activity mActivity = this;

    // ----------------------------------------------
    // Permission
    // ----------------------------------------------
    static final int REQUEST_CAMERA = 1;
    static final int REQUEST_WRITE_EXTERNAL_STORAGE = 2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);

        grantPermission(android.Manifest.permission.CAMERA, REQUEST_CAMERA);
    }

    /**
     * request permission
     * @param perm_str android.Manifest.permission.xxx
     * @param req_code REQUEST_xxx
     */
    private boolean grantPermission(String perm_str, int req_code) {
        int permission = ContextCompat.checkSelfPermission(mActivity, perm_str);
        if(permission != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(mActivity, new String[]{perm_str}, req_code);
            return false;
        }
        return true;
    }

    /**
     * Receive permission result
     * @param requestCode
     * @param permissions
     * @param grantResults
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        int idx;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            switch (requestCode) {
                case REQUEST_CAMERA:
                    for (idx = 0; idx < permissions.length; idx++) {
                        String permission = permissions[idx];
                        int grantResult = grantResults[idx];
                        if (permission.equals(android.Manifest.permission.CAMERA) && grantResult == PackageManager.PERMISSION_GRANTED) {
                            Log.v(TAG, "CAMERA Permitted");

                            // Restart this application
                            PackageManager packageManager = context.getPackageManager();
                            Intent intent = packageManager.getLaunchIntentForPackage(context.getPackageName());
                            ComponentName componentName = intent.getComponent();
                            Intent mainIntent = Intent.makeRestartActivityTask(componentName);
                            context.startActivity(mainIntent);
                            System.exit(0);
                            break;
                        }
                    }
                    if (idx == permissions.length) {
                        ShowEndProgram(); // End this program
                    }
                case REQUEST_WRITE_EXTERNAL_STORAGE:
                    for (idx = 0; idx < permissions.length; idx++) {
                        String permission = permissions[idx];
                        int grantResult = grantResults[idx];
                        if (permission.equals(android.Manifest.permission.WRITE_EXTERNAL_STORAGE) && grantResult == PackageManager.PERMISSION_GRANTED) {
                            Log.v(TAG, "WRITE_EXTERNAL_STORAGE Permitted");
                            break;
                        }
                    }
            }
        }
    }

    /**
     * Confirm stop or not
     */
    private void ShowEndProgram() {
        if (mActivity.isFinishing()) return; // to prevent BadTokenException

        if (ActivityCompat.shouldShowRequestPermissionRationale(this, android.Manifest.permission.CAMERA)) {
            showToastLong(getResources().getString(R.string.msg_need_camera_permission));
            startInstalledAppDetailsActivity(mActivity);
            finish();
        }
    }

    /**
     * Shows a {@link Toast} on the UI thread.
     *
     * @param text The message to show
     */
    private void showToastLong(final String text) {
        final Activity activity = mActivity;
        if (activity != null) {
            activity.runOnUiThread(new Runnable() {
                @Override
                public void run() {
                    Toast.makeText(activity, text, Toast.LENGTH_LONG).show();
                }
            });
        }
    }