1、android开发中一般用多个activity(分工明确);用一个activity会使一个java文件的代码过长
2、四大组件功能
activity显示界面
service提供后台服务,例如:下载文件
intent传递消息
contentProviderr存储数据
3、SurfaceHolder好像一个队列结构(先进先处理)
SurfaceHolder myholder = WelcomeView.this.getHolder();// 获取回调接口
Canvas canvas = myholder.lockCanvas();// 获取画布
try {
synchronized (myholder)// 同步
{
onDraw(canvas);// 进行绘制绘制
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if (canvas != null)// 如果当前画布不为空
{
myholder.unlockCanvasAndPost(canvas);// 解锁画布
}
}
4、FrameLayout帧布局
5、和服务器交互(通信)要点
HttpClient httpclient = new DefaultHttpClient();
// 你的URL
HttpPost httppost = new HttpPost(actionUrl);
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(
params.size());
for (Map.Entry<String, String> entry : params.entrySet()) {// 构建表单字段内容
nameValuePairs.add(new BasicNameValuePair(entry.getKey(),
MyConverter.escape(entry.getValue())));
}
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response;
response = httpclient.execute(httppost);
InputStream in = response.getEntity().getContent();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
int ch = 0;
while ((ch = in.read()) != -1) {
baos.write(ch);
}
byte[] data = baos.toByteArray();
baos.close();