如何在android studio中添加按钮点击事件

Question

所以我做了一些研究,并在通过代码将按钮定义为对象之后

private Button buttonname;
buttonname = (Button) findViewById(R.id.buttonnameinandroid) ;

这是我的问题

buttonname.setOnClickListener(this); //as I understand it, the "**this**" denotes the current `view(focus)` in the android program

然后你的OnClick()活动......

问题:

当我输入"this"时,它说:

setOnClickListener (Android.View.view.OnClickListener) in View cannot be applied to (com.helloandroidstudio.MainActivity)

我不知道为什么？

这是.java文件中的代码

import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

    private Button btnClick;
    private EditText Name, Date;
    private TextView msg, NameOut, DateOut;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btnClick = (Button) findViewById(R.id.button) ;
        btnClick.setOnClickListener(this);
        Name = (EditText) findViewById(R.id.textenter) ;
        Date = (EditText) findViewById(R.id.editText) ;
        msg = (TextView) findViewById(R.id.txtviewOut) ;
        NameOut = (TextView) findViewById(R.id.txtoutName) ;
        DateOut = (TextView) findViewById(R.id.txtOutDate) ;
        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment())
                    .commit();
        }
    }

    public void onClick(View v)
    {
        if (v == btnClick)
        {
            if (Name.equals("") == false && Date.equals("") == false)
            {
                NameOut = Name;
                DateOut = Date;
                msg.setVisibility(View.VISIBLE);
            }
            else
            {
                msg.setText("Please complete both fields");
                msg.setVisibility(View.VISIBLE);
            }
        }
        return;

    }

Answer 1

View中的SetOnClickListener(Android.View.view.OnClickListener)无法应用于(com.helloandroidstudio.MainActivity)

换句话说,这意味着(由于您当前的情况)您的MainActivity需要实现OnClickListener:

public class Main extends ActionBarActivity implements View.OnClickListener {
   // do your stuff
}

这个:

buttonname.setOnClickListener(this);

意味着您要为此按钮"在此实例上" 分配侦听器,->此实例表示OnClickListener,因此您的类必须实现该接口.

它与匿名监听器类(您也可以使用)类似:

buttonname.setOnClickListener(new View.OnClickListener() {

   @Override
   public void onClick(View view) {

   }
});

Answer 2

Button button= (Button)findViewById(R.id.buttonId);
button.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view) {
    // click handling code
   }
});

Answer 3

package com.mani.smsdetect;

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

public class MainActivity extends Activity implements View.OnClickListener {

    //Declaration Button
    Button btnClickMe;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        //Intialization Button

        btnClickMe = (Button) findViewById(R.id.btnClickMe);

        btnClickMe.setOnClickListener(MainActivity.this);
        //Here MainActivity.this is a Current Class Reference (context)
    }

    @Override
    public void onClick(View v) {

        //Your Logic
    }
}