토스트창을 띄우려고 하는데 저기서 왜 오류가날까요??
저렇게 쓰는게 맞는데...
 
package com.example.woong.btnevent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final Button btn1 = (Button) findViewById(R.id.btn1);
        final Button btn2 = (Button) findViewById(R.id.btn2);
        final Button btn3 = (Button) findViewById(R.id.btn3);
        final Button btn4 = (Button) findViewById(R.id.btn4);
        final EditText et = (EditText) findViewById(R.id.et1);
        View.OnClickListener listener = new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                    switch (v.getId())
                    {
                        case R.id.btn1:
                            et.setTextColor(0xFFFF0000);
                            break;
                        case R.id.btn2:
                            et.setTextColor(0xFF00FF00);
                            break;
                        case R.id.btn3:
                            et.setTextColor(0xFF0000FF);
                            break;
                        case R.id.btn4:
Toast.makeText(this, et.getText().toString(), Toast.LENGTH_LONG).show();   //여기 토스트를 띄우는 부분이 오류가나네요...
                            break;
                    }
            }
        };
        btn1.setOnClickListener(listener);
        btn2.setOnClickListener(listener);
        btn3.setOnClickListener(listener);
        btn4.setOnClickListener(listener);
    }
}