TestInput.java

public class TestInput extends AppCompatActivity {

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

        Button btn1 = (Button) findViewById(R.id.btn_1);
        btn1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(getApplicationContext(), "텍스트만 있는 버튼", Toast.LENGTH_SHORT).show();
            }
        });
        ImageButton btn2 = (ImageButton) findViewById(R.id.btn_2);
        btn2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(getApplicationContext(), "Icon만 있는 버튼", Toast.LENGTH_SHORT).show();
            }
        });
        Button btn3 = (Button) findViewById(R.id.btn_3);
        btn3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(getApplicationContext(), "Icon이 왼쪽에 있는 버튼", Toast.LENGTH_SHORT).show();
            }
        });
        Button btn4 = (Button) findViewById(R.id.btn_4);
        btn4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(getApplicationContext(), "Icon이 오른쪽에 있는 버튼", Toast.LENGTH_SHORT).show();
            }
        });
    }
}