button name cannot be resolved into a variable

the last question by me that was answered really help me. Thanks for all that. But now i am getting a new error. This is my code:

import android.app.Activity;
import android.os.Bundle;
import android.app.AlertDialog;
import android.view.View;

public class Trial extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        View b1 = findViewById(R.id.button1);
        b1.setOnClickListener(yourListener);  
        View b2 = findViewById(R.id.button2);
        b1.setOnClickListener(yourListener);  
    }
    View.OnClickListener yourListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (v == button1) {
                new AlertDialog.Builder(v.getContext())
                        .setTitle("Paracettamol")
                        .setMessage(
                                "This medicine is generally used to cure Fever")
                        .setNeutralButton("OK", null).show();
            } else if (v == button2) {
                new AlertDialog.Builder(v.getContext())
                        .setTitle("sertraline")
                       开发者_开发百科 .setMessage(
                                "This medicine is generally used to cure Head aches")
                        .setNeutralButton("OK", null).show();
            }


        }
    };
}

Firstly, i would like to tell you two things: 1)In the last line, i used to get an error that:"Syntax error,insert";" to complete FieldDeclaration. 2)I inserted";", and saved it , then i get an error with the if, and else if lines that "button1 cannot be resolved into a variable" and "button2 cannot be resolved into a variable" respectively.

My main.xml code is as follows:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
<Button android:id="@+id/button1" 
    android:layout_height="wrap_content" 
    android:layout_width="fill_parent" 
    android:text="@string/s1" 
    android:onClick="b1"/>
<Button android:id="@+id/button2" 
    android:layout_height="wrap_content" 
    android:text="Belladona" 
    android:layout_width="fill_parent" 
    android:onClick="b2"/>

</LinearLayout>

Please can anyone help me. Thanks in advance.

Well, button1 and button2 don't exist. You need to put R.id. before each of them.

Just use this condition:

if (v.getId() == R.id.button1) { /* ... */ }

You can even use switch with view ids if you have more controls.

Here is your java file

    import android.app.Activity;
    import android.os.Bundle;
    import android.app.AlertDialog;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;

public class Trial extends Activity implements OnClickListener {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button b1 = findViewById(R.id.button1);
        Button b2 = findViewById(R.id.button2);
        b1.setOnClickListener(this);
        b2.setOnClickListener(this);
    }


    @Override
    public void onClick(View v) {
        int id = v.getId();
        if (id == R.id.button1) {
            new AlertDialog.Builder(v.getContext())
                    .setTitle("Paracettamol")
                    .setMessage("This medicine is generally used to cure Fever")
                    .setNeutralButton("OK", null).show();
        } else if (id == R.id.button2) {
            new AlertDialog.Builder(v.getContext())
                    .setTitle("sertraline")
                    .setMessage(
                            "This medicine is generally used to cure Head aches")
                    .setNeutralButton("OK", null).show();
        }

    }
}

Here is your XML file

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
<Button android:id="@+id/button1" 
    android:layout_height="wrap_content" 
    android:layout_width="fill_parent" 
    android:text="@string/s1" 
    />
<Button android:id="@+id/button2" 
    android:layout_height="wrap_content" 
    android:text="Belladona" 
    android:layout_width="fill_parent" 
    />

</LinearLayout>

I have edited both of your files.. Hope it will help you.

You can try this one:

public class Trial extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Button b1 = (Button)findViewById(R.id.button1); 
        Button b2 = (Button)findViewById(R.id.button2);t

        b1.setOnClickListener(new OnClickListener(){
            public void onClick(View v) {
            if(b1.getText().equals("button1"))   //No need to check this condition 
            {
            //Your logic
            }
            }
    });


        b2.setOnClickListener(new OnClickListener(){
            public void onClick(View v) {
            if(b2.getText().equals("button2"))   //No need to check this condition 
            {
            //Your logic
            }
            }
    });

}

Try this code to solve your problem

 public class ButtonCheck extends Activity {
   /** Called when the activity is first created. */
 View b1,b2;
 @Override
     public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

     b1 = (View)findViewById(R.id.button1);
    b1.setOnClickListener(yourListener);  
  b2 =(View) findViewById(R.id.button2);
    b2.setOnClickListener(yourListener); 

}
View.OnClickListener yourListener=new OnClickListener() {

    @Override
    public void onClick(View v) {
        if (v ==b1) {
            new AlertDialog.Builder(v.getContext())
                    .setTitle("Paracettamol")
                    .setMessage(
                            "This medicine is generally used to cure Fever")
                    .setNeutralButton("OK", null).show();
        } else if (v ==b2) {
            new AlertDialog.Builder(v.getContext())
                    .setTitle("sertraline")
                    .setMessage(
                            "This medicine is generally used to cure Head aches")
                    .setNeutralButton("OK", null).show();
        }


    }
};
}

and hello if you get solved please check right and vote it up.

Instead of writing v == button1 which will always return false since both of them are different objects, you can use the equals method like this

if(v.equals(b1))
{
    ...................
}
else if(v.equals(b2))
{
    ................
}