String status=Environment.getExternalStorageState();
if(status.equals(Enviroment.MEDIA_MOUNTED))
{
说明有SD卡插入
}

2：让某个Activity透明

OnCreate中不设Layout this.setTheme(R.style.Theme_Transparent);
以下是Theme_Transparent的定义（注意transparent_bg是一副透明的图片）

3：在屏幕元素中设置句柄

使用Activity.findViewById来取得屏幕上的元素的句柄. 使用该句柄您可以设置或获取任何该对象外露的值.
TextView msgTextView = (TextView)findViewById(R.id.msg);
msgTextView.setText(R.string.push_me);

4：发送短信

String body=”this is mms demo”;
Intent mmsintent = new Intent(Intent.ACTION_SENDTO, Uri.fromParts(”smsto”, number, null));
mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_BODY, body);
mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_COMPOSE_MODE, true);
mmsintent.putExtra(Messaging.KEY_ACTION_SENDTO_EXIT_ON_SENT, true);
startActivity(mmsintent);

5：发送彩信

StringBuilder sb = new StringBuilder();
sb.append(”file://”);
sb.append(fd.getAbsoluteFile());
Intent intent = new Intent(Intent.ACTION_SENDTO, Uri.fromParts(”mmsto”, number, null));
// Below extra datas are all optional.
intent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_SUBJECT, subject);
intent.putExtra(Messaging.KEY_ACTION_SENDTO_MESSAGE_BODY, body);
intent.putExtra(Messaging.KEY_ACTION_SENDTO_CONTENT_URI, sb.toString());
intent.putExtra(Messaging.KEY_ACTION_SENDTO_COMPOSE_MODE, composeMode);
intent.putExtra(Messaging.KEY_ACTION_SENDTO_EXIT_ON_SENT, exitOnSent);
startActivity(intent);

6：发送Mail

mime = “img/jpg”;
shareIntent.setDataAndType(Uri.fromFile(fd), mime);
shareIntent.putExtra(Intent.EXTRA_STREAM, Uri.fromFile(fd));
shareIntent.putExtra(Intent.EXTRA_SUBJECT, subject);
shareIntent.putExtra(Intent.EXTRA_TEXT, body);

7：注册一个BroadcastReceiver

registerReceiver(mMasterResetReciever, new IntentFilter(”oms.action.MASTERRESET”));
private BroadcastReceiver mMasterResetReciever = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent){
String action = intent.getAction();
if(”oms.action.MASTERRESET”.equals(action)){
RecoverDefaultConfig();
}
}
};