初学Android，笔记1（view的引用和Button监听器的语法）

public class MainActivity extends AppCompatActivity {

    private TextView textview;
    private Button button;
    private int count = 0;
    @Override

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

        textview = (TextView)findViewById(R.id.textView);
        textview.setText("0");
        button = (Button)findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener(){
                public void onClick(View v){
                    count ++;
                    textview.setText(count + "");//不能直接加count，count// t为整形，要[count + ""]改成字符串
                }
        });
    }
}

模拟器运行结果：