android phone 6.0 对危险权限的判断

    //android phone 6.0 对危险权限的判断
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
        int hasWriteContactsPermission;
        hasWriteContactsPermission = checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE);
        if (hasWriteContactsPermission != PackageManager.PERMISSION_GRANTED) {

            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
                    CODE_FOR_WRITE_PERMISSION);
        }
    } else {
        initAll();
    }
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, 

@NonNull int[] grantResults) {
    if (requestCode == CODE_FOR_WRITE_PERMISSION) {
        if (permissions[0].equals(Manifest.permission.WRITE_EXTERNAL_STORAGE)
                && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            // 用户同意写文件
            initAll();
        } else {
            // 用户不同意，自行处理即可
            Toast.makeText(this, "你已经拒绝该权限", Toast.LENGTH_SHORT).show();
        }
    }
}