安卓实验（No.2）：Android Activity界面基础实验

    public class MainActivity extends AppCompatActivity {
    Button button;
    Button button2;
    Button button3;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button = (Button) findViewById(R.id.button1);
              button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //Intent intent = new Intent(MainActivity.this,DetailActivity.class);
                Intent intent =