當我鍵入CountDownTimer它不接受

Question

new CountDownTimer(30000, 1000) { 

public void onTick(long millisUntilFinished) { 
    mTextField.setText("seconds remaining: " + millisUntilFinished/1000); 
} 

public void onFinish() { 
    mTextField.setText("done!"); 
} 
}.start(); 

Answer 1

你必須輸入android.os.CountDownTimer。

試試這個：

import android.os.CountDownTimer; 

public class MainActivity extends AppCompatActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     ..................... 
     .............................. 

     new CountDownTimer(30000, 1000) { 

      public void onTick(long millisUntilFinished) { 
       mTextField.setText("seconds remaining: " + millisUntilFinished/1000); 
      } 

      public void onFinish() { 
       mTextField.setText("done!"); 
      } 
     }.start(); 

     ..................... 
     .............................. 
    } 
} 

Answer 2

如果您有任何Android平臺的jar（android.jar）作爲外部庫，你可以在你的類導入android.os.CountDownTimer。

導入後，你可以在你的類中創建CountDownTimer的對象：

new CountDownTimer(30000,1000) { 
      @Override 
      public void onTick(long millisUntilFinished) { 

      } 

      @Override 
      public void onFinish() { 

      } 
     }).start();