@SuppressLint(“StaticFieldLeak”)
private void initData() {
//做一个网络判断
if (!NetWork.isnetwork(MainActivity.this)) {
Toast.makeText(MainActivity.this, “无网络”, Toast.LENGTH_SHORT).show();
//调用dao层查询方法
List<NewsBean.DataBean> list = dao.list();
//判断是否为空
if (list.size() != 0) {
Madapter madapter = new Madapter(MainActivity.this, list);
plv.setAdapter(madapter);
}
return;
}
new AsyncTask<String, Void, List<NewsBean.DataBean>>() {
@Override
protected List<NewsBean.DataBean> doInBackground(String… strings) {
try {
URL url = new URL(strings[0]);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod(“GET”);
int responseCode = connection.getResponseCode();
if (responseCode == 200) {
InputStream inputStream = connection.getInputStream();
Gson gson = new Gson();
NewsBean newsBean = gson.fromJson(new BufferedReader(new InputStreamReader(inputStream)), NewsBean.class);
List<NewsBean.DataBean> data = newsBean.getData();
return data;
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(List<NewsBean.DataBean> dataBeans) {
super.onPostExecute(dataBeans);
if (page == 1) {
//集合必须创建
list = new ArrayList<>();
//清除数据库
dao.delete();
//添加数据库
dao.insert(dataBeans);
Toast.makeText(MainActivity.this, "缓存成功", Toast.LENGTH_SHORT).show();
}
list.addAll(dataBeans);
Madapter madapter = new Madapter(MainActivity.this, list);
plv.setAdapter(madapter);
}
}.execute(apiurl + page);
}
数据库
//添加数据库
public void insert(List<NewsBean.DataBean> list) {
for (int i = 0; i < list.size(); i++) {
ContentValues values = new ContentValues();
values.put("news_title", list.get(i).getNews_title());
values.put("news_summary", list.get(i).getNews_summary());
values.put("pic_url", list.get(i).getPic_url());
db.insert("news", null, values);
}
}
public List<NewsBean.DataBean> list() {
List<NewsBean.DataBean> list = new ArrayList<>();
Cursor cursor = db.query("news", null, null, null, null, null, null);
while (cursor.moveToNext()) {
//创建对象
NewsBean.DataBean dataBean = new NewsBean.DataBean();
String news_title = cursor.getString(cursor.getColumnIndex("news_title"));
String news_summary = cursor.getString(cursor.getColumnIndex("news_summary"));
dataBean.setNews_title(news_title);
dataBean.setNews_summary(news_summary);
//添加到集合
list.add(dataBean);
}
return list;
}
//删除
public void delete() {
db.delete("news", null, null);
}