//第一步：声明一个button
private Button button;
//实例化这个button
button = (Button) this.findViewById(R.id.button);
//给这个button添加onclick事件
button.setOnclickListener(new View.OnClickListener(){
@Override
public void onClick(View view){
Intent intent = new Intent(MainActivity.this, OtherActivity.class);
intent.putExtra("key","value");
startActivity(intent);
}
})