Http網路請求資料解析json展示資料+網路圖片展示+資料庫+Viewpager+Fragment
阿新 • • 發佈：2018-11-22
1.MainActivity主頁面
package com.bwie.guoxinyu; import android.support.v4.app.Fragment; import android.support.v4.app.FragmentActivity; import android.support.v4.app.FragmentPagerAdapter; import android.support.v4.view.ViewPager; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.widget.RadioGroup; import java.util.ArrayList; import java.util.List; public class MainActivity extends FragmentActivity { private ViewPager viewPager; private RadioGroup group; private List<Fragment> list; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //獲取資源id viewPager = findViewById(R.id.viewpage); group = findViewById(R.id.group); //例項化新增fragment list = new ArrayList<>(); list.add(new Fragmentone()); list.add(new Fragmenttwo()); list.add(new FragmentThree()); //建立介面卡 viewPager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) { @Override public Fragment getItem(int i) { return list.get(i); } @Override public int getCount() { return list.size(); } }); //滑動切換 viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int i, float v, int i1) { } @Override public void onPageSelected(int i) { switch (i){ case 0: group.check(R.id.btn1); break; case 1: group.check(R.id.btn2); break; case 2: group.check(R.id.btn3); break; } } @Override public void onPageScrollStateChanged(int i) { } }); //點選切換 group.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { @Override public void onCheckedChanged(RadioGroup group, int checkedId) { switch (checkedId){ case R.id.btn1: viewPager.setCurrentItem(0); break; case R.id.btn2: viewPager.setCurrentItem(1); break; case R.id.btn3: viewPager.setCurrentItem(2); break; } } }); } }
2.Bean類
package com.bwie.guoxinyu; import java.util.List; public class NewBean { private List<DataBean> data; public List<DataBean> getData() { return data; } public void setData(List<DataBean> data) { this.data = data; } public static class DataBean { private String news_id; private String news_title; private String news_summary; private String pic_url; public DataBean(String news_title, String news_summary, String pic_url) { this.news_title = news_title; this.news_summary = news_summary; this.pic_url = pic_url; } public String getNews_id() { return news_id; } public void setNews_id(String news_id) { this.news_id = news_id; } public String getNews_title() { return news_title; } public void setNews_title(String news_title) { this.news_title = news_title; } public String getNews_summary() { return news_summary; } public void setNews_summary(String news_summary) { this.news_summary = news_summary; } public String getPic_url() { return pic_url; } public void setPic_url(String pic_url) { this.pic_url = pic_url; } } }
3.介面卡頁面
package com.bwie.guoxinyu; import android.content.Context; import android.graphics.Bitmap; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.TextView; import java.util.ArrayList; import java.util.List; public class NewAdaper extends BaseAdapter { private List<NewBean.DataBean> mData; private Context mContext; public NewAdaper(Context mContext) { this.mContext = mContext; //初始化 mData = new ArrayList<>(); } //傳遞值得方法 共外部傳值 public void setmData(List<NewBean.DataBean> datas){ this.mData = datas; notifyDataSetChanged(); } //刪除的方法 public void delData(int position){ mData.remove(position); notifyDataSetChanged(); } @Override public int getCount() { return mData.size(); } @Override public NewBean.DataBean getItem(int position) { return mData.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder; //判斷是否為空 if(convertView == null){ //載入子佈局 convertView = LayoutInflater.from(mContext).inflate(R.layout.newitem,parent,false); holder = new ViewHolder(convertView); }else{ //複用 holder = (ViewHolder) convertView.getTag(); } //定義賦值的方法 holder.bind(getItem(position)); return convertView; } //暫存器 class ViewHolder{ TextView title; TextView summary; ImageView image; //獲取子佈局id的方法 public ViewHolder(View convertView) { title = convertView.findViewById(R.id.title); summary = convertView.findViewById(R.id.summary); image = convertView.findViewById(R.id.image); convertView.setTag(this); } //賦值的方法 public void bind(NewBean.DataBean item) { title.setText(item.getNews_title()); summary.setText(item.getNews_summary()); //NetUtil.loadImage(item.getPic_url(),image); //每次都繫結最新的url到image image.setTag(item.getPic_url()); //當載入完成，判斷當前載入圖片的url是否和繫結的一樣 NetUtil.loadImage(item.getPic_url(), new NetUtil.CallBack() { @Override public void loadImageSuccess(String urlImage, Bitmap bitmap) { //判斷當前載入圖片的url是否和繫結的一樣 if(image.getTag().equals(urlImage)){ image.setImageBitmap(bitmap); } } }); } } }
4.工具類頁面
package com.bwie.guoxinyu;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.widget.ImageView;
import com.google.gson.Gson;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class NetUtil {
//網路請求資料的方法
public static String setRquest(String urlStr){
String json = "";
try {
//開啟url地址
URL url = new URL(urlStr);
//開啟連線
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
//設定請求方式
urlConnection.setRequestMethod("GET");
//設定超時
urlConnection.setReadTimeout(5000);
urlConnection.setConnectTimeout(5000);
//設定請求碼
int responseCode = urlConnection.getResponseCode();
if(responseCode == 200){
json = stream2String(urlConnection.getInputStream());
}
} catch (Exception e) {
e.printStackTrace();
}
return json;
}
//將位元組流轉換為字元流
private static String stream2String(InputStream inputStream) throws IOException {
InputStreamReader isr = new InputStreamReader(inputStream);
BufferedReader br = new BufferedReader(isr);
StringBuilder builder = new StringBuilder();
for (String tmp = br.readLine();tmp!=null;tmp = br.readLine()){
builder.append(tmp);
}
return builder.toString();
}
//解析json的方法 返回bean
public static <E> E setRquest(String urlStr,Class clazz){
String rquest = setRquest(urlStr);
E e = (E) new Gson().fromJson(rquest, clazz);
return e;
}
//載入圖片的方法
public static Bitmap loadImage(String urlImage){
Bitmap bitmap =null;
try {
//開啟url地址
URL url = new URL(urlImage);
//開啟連線
HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
//設定請求方式
urlConnection.setRequestMethod("GET");
//設定超時
urlConnection.setReadTimeout(5000);
urlConnection.setConnectTimeout(5000);
//設定請求碼
int responseCode = urlConnection.getResponseCode();
if(responseCode == 200){
//將讀取出來的內容存入bitmap
bitmap = BitmapFactory.decodeStream(urlConnection.getInputStream());
}
} catch (Exception e) {
e.printStackTrace();
}
return bitmap;
}
//定義介面
public interface CallBack{
public void loadImageSuccess(String urlImage,Bitmap bitmap);
}
//獲取圖片的方法
public static void loadImage(final String urlImage, final CallBack callBack){
new AsyncTask<String,Void,Bitmap>(){
@Override
protected Bitmap doInBackground(String... strings) {
return NetUtil.loadImage(strings[0]);
}
@Override
protected void onPostExecute(Bitmap bitmap) {
callBack.loadImageSuccess(urlImage,bitmap);
}
}.execute(urlImage);
}
}
5.資料庫建立表頁面
package com.bwie.guoxinyu;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class SqliteHelper extends SQLiteOpenHelper {
public SqliteHelper( Context context) {
super(context, "New.db", null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
//建立表
db.execSQL("create table news(id integer primary key autoincrement," +
"news_title text," +
"news_summary text," +
"pic_url text)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
6.資料庫方法頁面增刪改查
package com.bwie.guoxinyu;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import java.util.ArrayList;
import java.util.List;
public class NewDao {
private final SqliteHelper helper;
private final SQLiteDatabase sb;
public NewDao(Context context){
//建立資料庫
helper = new SqliteHelper(context);
sb = helper.getReadableDatabase();
}
//新增
public void add(String news_title,String news_summary,String pic_url){
ContentValues values = new ContentValues();
values.put("news_title",news_title);
values.put("news_summary",news_summary);
values.put("pic_url",pic_url);
sb.insert("news",null,values);
}
//查詢
public List<NewBean.DataBean> select(){
Cursor news = sb.query("news", null, null, null, null, null, null);
List<NewBean.DataBean> list = new ArrayList<>();
while (news.moveToNext()){
String news_title = news.getString(news.getColumnIndex("news_title"));
String news_summary = news.getString(news.getColumnIndex("news_summary"));
String pic_url = news.getString(news.getColumnIndex("pic_url"));
NewBean.DataBean bean = new NewBean.DataBean(news_title,news_summary,pic_url);
list.add(bean);
}
return list;
}
//刪除
public void delete(String news_title){
sb.delete("news","news_title = ?",new String[]{news_title});
}
}
7.Fragment內容頁面
package com.bwie.guoxinyu;
import android.annotation.SuppressLint;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;
public class Fragmentone extends Fragment {
private ListView listView;
private NewAdaper mAdaper;
private NewDao dao;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
//載入佈局
View view = inflater.inflate(R.layout.fragmentone, container, false);
//獲取資源id
listView = view.findViewById(R.id.lv_list);
//建立介面卡
mAdaper = new NewAdaper(getActivity());
listView.setAdapter(mAdaper);
dao = new NewDao(getActivity());
return view;
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
//長按刪除
listView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
dao.delete(mAdaper.getItem(position).getNews_title());
mAdaper.delData(position);
return true;
}
});
infoDta();
}
private String urlStr = "http://api.expoon.com/AppNews/getNewsList/type/1/p/1";
@SuppressLint("StaticFieldLeak")
private void infoDta() {
new AsyncTask<String, Void, List<NewBean.DataBean>>() {
@Override
protected List<NewBean.DataBean> doInBackground(String... strings) {
List<NewBean.DataBean> data = new ArrayList<>();
//迴圈陣列 將資料新增到集合中
for (String url : strings) {
NewBean bean = NetUtil.setRquest(url, NewBean.class);
data.addAll(bean.getData());
}
//判斷資料庫是否有資料，沒有資料向資料庫新增資料
if (dao.select().size() == 0) {
for (NewBean.DataBean d : data) {
String news_title = d.getNews_title();
String news_summary = d.getNews_summary();
String pic_url = d.getPic_url();
//新增資料庫
dao.add(news_title, news_summary, pic_url);
}
}
//查詢資料庫
List<NewBean.DataBean> select = dao.select();
return select;
}
@Override
protected void onPostExecute(List<NewBean.DataBean> dataBeans) {
mAdaper.setmData(dataBeans);
}
}.execute(urlStr);
}
}