Question

我的代码存在问题。我正在用相机拍照，然后将图像上传到firebase存储。但是，我正在向数据库添加其他数据，它也包含照片网址。上面的脚本开始将图像上传到存储，但代码的其他部分将无法工作，因为this.picurl仅在上载过程完成后才有值。

我怎么能添加一个序列，所以当this.picurl = savepic.downloadURL终于可用时（图片上传成功），其余的代码将会运行。

 public class NewActivity extends AppCompatActivity {

 protected void onCreate(Bundle savedInstanceState){

    ListView listfavorites = findViewById(R.id.favorites);

 try{
       SQLiteOpenHelper helper = new DataBaseHelper(this);  
       SQLiteDatabase db = helper.getReadableDatabase();

//   Now with this query, my list is filled with all the data, when I tickle
 // which object is the favorite.

 Cursor favorite = db.rawQuery ("SELECT CARS._id, PLANES._id,
 CARS.NAME, PLANES.NAME FROM CARS, 
PLANES WHERE
   CARS.FAVORITE=1 AND 
PLANES.FAVORITE=1, null);

    CursorAdapter favoriteAdapter = new 
 SimpleCursorAdapter(NewActivity.this,               
   android.R.layout.simple_list_item_1, 
 favorite,  
new String[]{"NAME",
   new int[]}{android.R.id.text1},0);

   listfavorites.setAdapter(favoriteAdapter); 

          }catch(SQLite Exception e){
          Toast.makeText(this, "Database not available", 
          Toast.LENGTH_SHORT).show();   }


// By the way, if I already have a list filled up with data and I   
// would like to go to the corresponding activity, how to do it    if
// the    list is filled with eg 2-3 activity?    

  listfavorites.setOnItemClickListener(new AdapterView.OnItemClickListener(){     

          public void onItemClick(AdapterView<?> parent, View view, int position, long id){
             Intent intent = new Intent(this, Cars.class);       
             intent.putExtra(Cars.EXTRA_CAR, (int)id);     
             startActivity(intent);
           } });

              }
             }

Answer 1

您可以将package loginmenu; import java.util.Scanner; public class LoginMenu { private static String correctPassword; public static String userPassword; public static int attemptsCounter; public static boolean loggedIn; public static void main(String[] args) { showMenu(); loginAttempt(); } public static void showMenu() // displays a menu and keeps displaying until user chooses the QUIT option { int userChoice; Scanner myScan = new Scanner(System.in); do { System.out.println("1. Login"); System.out.println("2. Change Password"); System.out.println("3. Change Attempts"); System.out.println("4. Quit"); userChoice = myScan.nextInt(); switch (userChoice) { case 1: { System.out.println("You chose to login."); loginAttempt(); break; } case 2: { System.out.println("You chose to change password."); Scanner myNewScan = new Scanner(System.in); System.out.println("Please enter a password."); userPassword = myNewScan.nextLine(); break; } case 3: { System.out.println("You chose to change attempts."); Scanner myNewScan = new Scanner(System.in); System.out.println("Please enter amount of attempts."); attemptsCounter = myNewScan.nextInt(); break; } case 4: { System.out.println("You have quit the program."); break; } default: { System.out.println("Not a valid choice."); } }// closes switch } while (userChoice != 4); myScan.close(); System.out.println("Goodbye."); }// closes showMenu1 public static void loginAttempt() { Scanner scan = new Scanner(System.in); while (correctPassword != userPassword) && (attemptsCounter>=5); { System.out.println("Please change password and attempts first."); showMenu(); } if (userPassword == correctPassword) && (attemptsCounter<=5) { System.out.println("You entered the correct password in " + attemptsCounter + " attempts"); } if (attemptsCounter>=6) { System.out.println("You have been locked out."); } } }块放入当时的回调中，也可以使用async / await来执行此操作：

firebase.list

仅在图像上传完成后上传附加数据（序列？）

1 个答案: