Java 如何将方法添加到活动中，并在单击按钮时调用该方法

有人能帮我补充一下：

/** Called when the user clicks the Send button. */
public void sendMessage(View view) {
    // Do something in response to button
}

为此，主要活动包括：

我如何将这些结合起来并使其工作

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {

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

/** Called when the user clicks the Send button */
public void sendMessage(View view) {
    // Do something in response to button
}

}

创建完成后，您需要将其添加到下面的任意位置，如下所示：

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {

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

    /** Called when the user clicks the Send button */
    public void sendMessage(View view) {
        // Do something in response to button 
    }
}

我假设xml中的按钮包含android:onClick=sendMessage

在activity_main.xml上使用如下内容： 在strings.xml上添加以下行：

---

我可以知道投反对票的原因吗？

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {

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

    /** Called when the user clicks the Send button */
    public void sendMessage(View view) {
        // Do something in response to button 
    }
}

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity {

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

/** Called when the user clicks the Send button */
public void sendMessage(View view) {`enter code here`
   // Do something in response to button
}
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="sendMessage"
    android:text="@string/button_send" />
</LinearLayout>

<string name="button_send">Send</string>