如何使用Onclick更改按钮背景

Question

import android.app.Activity;
import android.graphics.Color;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;


public class MainActivity extends Activity {
   private Button buton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        buton = (Button) findViewById(R.id.buton_verde);

        View.OnClickListener clickListener = new View.OnClickListener() {
            public void OnClick(View b) {
                if (buton == b) {
                    buton.setBackgroundColor(Color.GREEN);
            }
        };
    }
}

Something is wrong. I do not get it. I want to have a button and on click to change its color to green or to a specific color code.

How can I change the background of a layer with a button?

Answer 1

Add the listener to your button:

@Override
protected void onCreate(Bundle savedInstanceState) {

   super.onCreate(savedInstanceState);
   setContentView(R.layout.activity_main);

 buton = (Button) findViewById(R.id.buton_verde);
 buton.setOnClickListener(new View.OnClickListener() {
 @Override
 public void onClick(View v) {
        buton.setBackgroundColor(Color.GREEN);

 });
}

And remove the if statement:

 if (buton == b) {
 ...

Answer 2

 import android.app.Activity;
  import android.graphics.Color;
  import android.support.v7.app.ActionBarActivity;
 import android.os.Bundle;
       import android.view.Menu;
                  import android.view.MenuItem;
       import android.view.View;
          import android.widget.Button;


     public class MainActivity extends Activity {
       private Button buton;

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    buton = (Button) findViewById(R.id.buton_verde);
    buton.setOnClickListener(clickListener);
}

View.OnClickListener clickListener = new View.OnClickListener() {
    public void onClick(View v) {
        if (buton == v)
            buton.setBackgroundColor(Color.GREEN);
    }
};

}

Answer 3

Here's your fixed code. it's all explained in the comments.

import android.app.Activity;
import android.graphics.Color;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;

public class MainActivity extends Activity {
private Button button; // Renamed to button, not buton

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Use English words, others might read your code someday
    button = (Button) findViewById(R.id.buton_verde); 

    View.OnClickListener clickListener = new View.OnClickListener() {
        @Override
        public void onClick(View b) {
            button.setBackgroundColor(Color.GREEN);
            // You are explicitly assiging the OnClickListener for this button
            // Thus, you don't need to check if b is a button
        }
    };
    // You have created the listener, now you need to assign it to the button
    button.setOnClickListener(clickListener); 
    }
}