Android判断某个权限是否开启的方法

/**
 * 读写权限 自己可以添加需要判断的权限
 */
public static String[]permissionsREAD={
    Manifest.permission.READ_EXTERNAL_STORAGE,
    Manifest.permission.WRITE_EXTERNAL_STORAGE };

/**
 * 判断权限集合
 * permissions 权限数组
 * return true-表示没有改权限 false-表示权限已开启
 */
public static boolean lacksPermissions(Context mContexts,permissionsREAD) {
  for (String permission : permissions) {
    if (lacksPermission(mContexts,permission)) {
      return true;
    }
  }
  return false;
}

/**
 * 判断是否缺少权限
 */
private static boolean lacksPermission(Context mContexts, String permission) {
  return ContextCompat.checkSelfPermission(mContexts, permission) ==
      PackageManager.PERMISSION_DENIED;
}

if (lacksPermissions()){//读写权限没开启
  ActivityCompat.requestPermissions(this,permissionsREAD,0);
}else {
  //读写权限已开启
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
  super.onRequestPermissionsResult(requestCode, permissions, grantResults);
  if (requestCode==0){
    for (int i = 0; i < permissions.length; i++) {
      if (grantResults[i]!=-1){
        //T.showShort(mContext,"权限设置成功");
        
      }else {
        //T.showShort(mContext,"拒绝权限");
        // 权限被拒绝，弹出dialog 提示去开启权限
        showPermissions();
        break;
      }
    }

  }
}

//弹出dialog

private void showPermissions(){
  final Dialog dialog=new android.app.AlertDialog.Builder(mContext).create();
  View v=LayoutInflater.from(mContext).inflate(R.layout.dialog_permissions,null);
  dialog.show();
  dialog.setContentView(v);

  Button btn_add= (Button) v.findViewById(R.id.btn_add);
  Button btn_diss= (Button) v.findViewById(R.id.btn_diss);

  btn_add.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
      dialog.dismiss();
      Intent intent = new Intent();
      intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
      intent.addCategory(Intent.CATEGORY_DEFAULT);
      intent.setData(Uri.parse("package:" + getPackageName()));
      intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
      intent.addFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
      intent.addFlags(Intent.FLAG_ACTIVITY_EXCLUDE_FROM_RECENTS);
      startActivity(intent);
    }
  });

  btn_diss.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
      dialog.dismiss();
    }
  });
}