MainActivity
public class MainActivity extends AppCompatActivity {
private String mUrl = "https://suggest.taobao.com/sug?code=utf-8&q=%E6%89%8B%E6%9C%BA";
private ListView lv;
private List<List<String>> mList = new ArrayList<>();
private MyAdapter adapter;
private ContentResolver resolver;
private Uri uri;
private int i;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
adapter = new MyAdapter(MainActivity.this, mList);
lv.setAdapter(adapter);
resolver = getContentResolver();
uri = Uri.parse("content://com.bawei.diyizhoumoni1.provider.provider.MyProvider/user");
//判断有网没网
if(isNetworkConnected(MainActivity.this)){
Cursor cursor = resolver.query(uri, null, null, null, null);
if(cursor.getCount()==0){
new MyTask().execute(mUrl);
Toast.makeText(MainActivity.this,"请求数据",Toast.LENGTH_SHORT).show();
}else{
Toast.makeText(MainActivity.this,"有网，已经请求过数据并且保存到了数据库",Toast.LENGTH_SHORT).show();
Cursor query = resolver.query(uri, null, null, null, null);
while (query.moveToNext()){
String neirong = query.getString(query.getColumnIndex("neirong"));
mList.add(Collections.singletonList(neirong));
}
adapter.setList(mList);
}
}else{
Toast.makeText(MainActivity.this,"没有联网,从数据库请求数据",Toast.LENGTH_SHORT).show();
Cursor cursorw = resolver.query(uri, null, null, null, null);
if(cursorw.getCount()==0){
Toast.makeText(MainActivity.this,"数据库没有数据",Toast.LENGTH_SHORT).show();
}else {
while (cursorw.moveToNext()) {
String neirong = cursorw.getString(cursorw.getColumnIndex("neirong"));
mList.add(Collections.singletonList(neirong));
}
adapter.setList(mList);
}
}
//条目长点击事件
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, final int position, long id) {
AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
builder.setTitle("这是标题");
builder.setMessage("确认要删除吗？");
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
resolver.delete(uri, "neirong=?", new String[]{mList.get(position).toString()});
Toast.makeText(MainActivity.this,"删除成功",Toast.LENGTH_SHORT).show();
mList.remove(position);
adapter.notifyDataSetChanged();
}
});
builder.setNegativeButton("取消", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
});
AlertDialog d = builder.create();
d.show();
return false;
}
});
}
private void initView() {
lv = findViewById(R.id.Show_lv);
}
class MyTask extends AsyncTask<String, View, List<List<String>>> {
@Override
protected List<List<String>> doInBackground(String... strings) {
try {
URL url = new URL(strings[0]);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
if (connection.getResponseCode() == 200) {
InputStream stream = connection.getInputStream();
String getstr = getstr(stream);
Gson gson = new Gson();
MyData myData = gson.fromJson(getstr, MyData.class);
// Log.d("aaa",myData.toString());
mList=myData.getResult();
for (int i=0;i<mList.size();i++){
ContentValues values=new ContentValues();
values.put("neirong",mList.get(i).toString());
resolver.insert(uri,values);
}
return mList;
}
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(List<List<String>> lists) {
super.onPostExecute(lists);
adapter.setList((List<List<String>>) lists);
}
}
public boolean isNetworkConnected(Context context) {
if (context != null) {
ConnectivityManager mConnectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo mNetworkInfo = mConnectivityManager.getActiveNetworkInfo();
if (mNetworkInfo != null) {
return mNetworkInfo.isAvailable();
}
}
return false;
}
//转换
private String getstr(InputStream stream) throws IOException {
BufferedReader bf = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String con = null;
while ((con = bf.readLine()) != null) {
buffer.append(con);
}
return buffer.toString();
}
}
//适配器
package com.bawei.diyizhoumoni1.adapter;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;
import com.bawei.diyizhoumoni1.R;
import java.util.List;
public class MyAdapter extends BaseAdapter {
private Context mContext;
private List<List> mList;
public MyAdapter(Context mContext, List<List<String>> mList) {
this.mContext = mContext;
this.mList = mList;
}
public void setList (List<List<String>> list){
this.mList=list;
notifyDataSetChanged();
}
@Override
public int getCount() {
return mList.size();
}
@Override
public Object getItem(int position) {
return null;
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if(convertView==null){
convertView=View.inflate(mContext, R.layout.list_item,null);
holder=new ViewHolder();
holder.tv=convertView.findViewById(R.id.Text_tv);
convertView.setTag(holder);
}else{
holder=(ViewHolder)convertView.getTag();
}
holder.tv.setText(mList.get(position).toString());
return convertView;
}
class ViewHolder{
TextView tv;
}
}
//数据库
package com.bawei.diyizhoumoni1.helper;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class MyHelper extends SQLiteOpenHelper {
public MyHelper(Context context) {
super(context, “BBB”, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
String sql="create table if not exists user(uid integer primary key autoincrement,neirong text)";
db.execSQL(sql);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
//增删该查
package com.bawei.diyizhoumoni1.provider;
import android.content.ContentProvider;
import android.content.ContentValues;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import com.bawei.diyizhoumoni1.helper.MyHelper;
public class MyProvider extends ContentProvider {
private int i;
private static UriMatcher um=new UriMatcher(UriMatcher.NO_MATCH);
static {
um.addURI("com.bawei.diyizhoumoni1.provider.provider.MyProvider","user",100);
}
private SQLiteDatabase db;
@Override
public boolean onCreate() {
MyHelper helper = new MyHelper(getContext());
db = helper.getWritableDatabase();
return false;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
Cursor cursor = db.query("user", null, null, null, null, null, null);
return cursor;
}
@Override
public String getType(Uri uri) {
return null;
}
@Override
public Uri insert(Uri uri, ContentValues values) {
switch (um.match(uri)){
case 100:
db.insert("user",null,values);
break;
}
return null;
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
switch (um.match(uri)){
case 100:
i = db.delete("user", selection, selectionArgs);
break;
}
return i;
}
@Override
public int update(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
return 0;
}
}
//清单文件
<?xml version="1.0" encoding="utf-8"?><uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<provider
android:authorities="com.bawei.diyizhoumoni1.provider.provider.MyProvider"
android:name="com.bawei.diyizhoumoni1.provider.MyProvider"
android:exported="true"></provider>
</application>
仅供参考！！！