Android button four kinds of basic -1.0 click event

The first test uses

Xml directly add, more usually use in their test the demo.

1, add a click event to the button directly in xml

android:onClick="btn_click"

2, hold down the option + enter to btn_click quickly create activity codes

    public  void btn_Click (View View) {
         // Sout 
        System.out.println ( "Ha ha ha, I was clicked" );
        Toast.makeText ( the this , "Ha ha ha, I was clicked" , Toast.LENGTH_SHORT) .Show ();
    }

The second lot of buttons

When the button has a lot of time, you can use this kind of

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

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

        Button btn_click = findViewById(R.id.button);
        btn_click.setOnClickListener(this);
    }

    @Override void public onClick (View v) {System.out.println ( "Ha ha ha, I was clicked 3" ); Toast.makeText (MainActivity.this, "Ha ha ha, I clicked the 3" , Toast.LENGTH_SHORT). show ();}}

Button many cases

        btn_call.setOnClickListener(this);
    btn_call2.setOnClickListener(this);
    btn_call3.setOnClickListener(this);
    btn_call4.setOnClickListener(this);



    @Override
    public void onClick(View v) {
        switch (v.getId()) {
        case R.id.button1: 
  
            callPhone();
            break;

        case R.id.button2: 
            callPhone();
            break;

        case R.id.button3: 
            callPhone();
            break;

        case R.id.button4: 

            System.out.println ( "ha ha ha" );
             BREAK ;

        default:
            break;
        }

    }    

The third internal class (common)

Define an inner class to implement the button click event

Note: This method will overwrite the first

public class MainActivity extends AppCompatActivity {

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

        Button btn_click = findViewById(R.id.button);
        btn_click.setOnClickListener(new  MyClickListener());
    }

    class MyClickListener implements View.OnClickListener {
        @Override
        public void onClick(View v) {
            System.out.println ( "Ha ha ha, I clicked 2" );
            Toast.makeText (. MainActivity the this , "Ha ha ha, I was clicked 2" , Toast.LENGTH_SHORT) .Show ();
        }
    }

}

The fourth anonymous inner classes (common)

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

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

        Button btn_click = findViewById(R.id.button);
        btn_click.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                System.out.println ( "Ha ha ha, I clicked 4" );
                Toast.makeText (. MainActivity the this , "Ha ha ha, I clicked the 4" , Toast.LENGTH_SHORT) .Show ();
            }
        });
    }
}