我的是我的setOnClickListener給我一個錯誤？

Question

當我將鼠標懸停在「setOnClickListener」下方的紅色曲線上時，彈出消息顯示「無法解析符號setOnClickListener」，「@Override」顯示「此處不允許註釋」。而「View v」中的v也給我一個錯誤。我在哪裏搞砸了？

import android.content.Intent; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.Button; 

public class EmailReceiptActivity extends AppCompatActivity { 


@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_email_receipt); 

} 

@Override 
public boolean onCreateOptionsMenu(Menu menu) { 
    getMenuInflater().inflate(R.menu.main_options_menu, menu); 
    menu.findItem(R.menu.main_options_menu).setIntent(
      new Intent(EmailReceiptActivity.this, LaunchActivity.class)); 
    return true; 
} 

@Override 
public boolean onOptionsItemSelected(MenuItem item) { 
    int id = item.getItemId(); 
    //use the id of the item from main_options_menu 
    if (id == R.id.logoff_menu_item) { 
     super.onOptionsItemSelected(item); 
     startActivity(item.getIntent()); 
    } 

    return true; 
} 

Button btn_send = (Button)findViewById(R.id.send_receipt_button); 
btn_send.setOnClickListener(new View.OnClickListener(){ 
    @Override 
    //Use the name of the function you assigned to the xml design of the button 
    public void onClick(View v){ 
     //Use the name of this class, and the name class where you want to be taken when the button is clicked. 
     startActivity (new Intent(EmailReceiptActivity.this, SuccessActivity.class)); 
    } 
} 

}

Answer 1

如果要在代碼移動到如onCreate方法內的onClickListener進行設置。你不能在函數體外執行那樣的代碼。此外，它可能更有用一個更全局範圍來聲明Button的onCreate外面，所以儘量...

public Button btn_send; 

protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_email_receipt); 

    btn_send = (Button)findViewById(R.id.send_receipt_button); 
    btn_send.setOnClickListener(new View.OnClickListener(){ 
     @Override 
     //Use the name of the function you assigned to the xml design of the button 
     public void onClick(View v){ 
      //Use the name of this class, and the name class where you want to be taken when the button is clicked. 
      startActivity (new Intent(EmailReceiptActivity.this, SuccessActivity.class)); 
    } 
} 

Answer 2

個人按鈕send_receipt_button;

public class GameOver extends AppCompatActivity implements View.OnClickListener { 

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

      setContentView(R.layout.activity_email_receipt); 
       Button btn_send = (ImageButton) findViewById(R.id.send_receipt_button); 
      btn_send.setOnClickListener(this); 

} 

    public void onClick (View v){ 



      switch (v.getId()) { 

       case R.id.send_receipt_button: 
        startActivity (new Intent(EmailReceiptActivity.this, SuccessActivity.class)); 


        break; 
} 
} 

Answer 3

，如果你想要把你OnClickListener外面這樣，那麼就應該是這樣的：

OnClickListener sendListener = new View.OnClickListener(){ 
    @Override 
    //Use the name of the function you assigned to the xml design of the button 
    public void onClick(View v){ 
     //Use the name of this class, and the name class where you want to be taken when the button is clicked. 
     startActivity (new Intent(EmailReceiptActivity.this, SuccessActivity.class)); 
    } 
}; 

然後將其設置在一個地區像onCreate

Button btn_send; 
protected void onCreate(Bundle savedInstanceState) { 
    ... 

    btn_send.setOnClickListener(sendListener); 
} 

但最好，您希望將您的findViewById和您的OnClickListener移動到一個區域，如onCreate

Button btn_send; 
protected void onCreate(Bundle savedInstanceState) { 
    ... 

    btn_send = (Button)findViewById(R.id.send_receipt_button); 
    btn_send.setOnClickListener(new View.OnClickListener(){ 
     @Override 
     //Use the name of the function you assigned to the xml design of the button 
     public void onClick(View v){ 
      //Use the name of this class, and the name class where you want to be taken when the button is clicked. 
      startActivity (new Intent(EmailReceiptActivity.this, SuccessActivity.class)); 
    } 
}