public class AppMainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) {  super.onCreate(savedInstanceState);  setContentView(R.layout.activity_main);  //在App中需要請求權限才能執行用戶的操作  getPermissionToReadUserContacts(); } //定義請求 private static final int READ_CONTACTS_REQUEST = 1; //當用戶執行的操作需要權限時候進行詢問 public void getPermissionToReadUserContacts() {  /**   * 1)使用ContextCompat.chefkSelfPermission(),因為Context.permission   * 只在棒棒糖系統中使用   * 2）總是檢查權限（即使權限被授予）因為用戶可能會在設置中移除你的權限*/  if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)    != PackageManager.PERMISSION_GRANTED ||    ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)      != PackageManager.PERMISSION_GRANTED ||    ContextCompat.checkSelfPermission(this, Manifest.permission.READ_PHONE_STATE)      != PackageManager.PERMISSION_GRANTED) {   //權限為獲取，檢查用戶是否被詢問過并且拒絕了，如果是這樣的話，給予更多   //解釋   if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION) ||     ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_EXTERNAL_STORAGE) ||     ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_PHONE_STATE)) {    //在界面上展示為什么需要讀取聯系人    Toast.makeText(this, "需要定位位置權限,手機電話權限和存儲權限才可以正常工作", Toast.LENGTH_SHORT).show();   }   //發起請求獲得用戶許可,可以在此請求多個權限   ActivityCompat.requestPermissions(this, new String[]{       Manifest.permission.ACCESS_FINE_LOCATION,       Manifest.permission.READ_EXTERNAL_STORAGE,       Manifest.permission.READ_PHONE_STATE},     READ_CONTACTS_REQUEST);  } } //從requestPermissions()方法回調結果 @Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {  //確保是我們的請求  if (requestCode == READ_CONTACTS_REQUEST) {   if (grantResults.length == 3 && grantResults[0] == PackageManager.PERMISSION_GRANTED     && grantResults[1] == PackageManager.PERMISSION_GRANTED       && grantResults[2] == PackageManager.PERMISSION_GRANTED) {    System.out.println("應用權限獲取成功");   } else {    System.out.println("應用權限獲取失敗");   }  } else {   super.onRequestPermissionsResult(requestCode, permissions, grantResults);  } }}