我的 setOnClickListener 给我一个错误吗？ [复制]

Question

当我将鼠标悬停在“setOnClickListener”下的波浪形红线上时，弹出消息“无法解析符号 setOnClickListener”，“@Override”显示“此处不允许注释”。而“View v”中的 v 也给了我一个错误。我哪里搞砸了？

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

您应该将代码移至 onCreate 等方法中，以便设置 onClickListener。你不能在函数体之外执行这样的代码。此外，在onCreate 之外使用更全局的范围声明您的Button 可能更有用，所以请尝试...

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

如果你想把你的OnClickListener 放在外面，那么应该是这样的：

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));
    }
};

然后你将它设置在像onCreate这样的区域

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

    btn_send.setOnClickListener(sendListener);
}

但理想情况下，您希望将您的 findViewById 和您的 OnClickListener 移动到像 onCreate 这样的区域

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));
    }
}

Answer 3

私人按钮 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;
}
}