写一个dialog

new AlertDialog.Builder(MainActivity.this).setTitle("有更新").setMessage("最新版本4.2.2")

.setPositiveButton("更新", new OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {

Intent intent = new Intent(MainActivity.this, UpdateService.class);

intent.putExtra("apkUrl", "http://");

startService(intent);

}

}).setNegativeButton("取消", new OnClickListener() {

@Override

public void onClick(DialogInterface dialog, int which) {

finish();

}

}).show();