Android之网络数据存储

 一、网络保存数据介绍

可以使用网络来保存数据，在需要的时候从网络上获取数据，进而显示在App中。

用网络保存数据的方法有很多种，对于不同的网络数据采用不同的上传与获取方法。

本文利用LeanCloud来进行网络数据的存储。

LeanCloud是一种简单高效的数据和文件存储服务。感兴趣的可以查看网址：https://leancloud.cn/。关于LeanCloud的数据存储使用方法可以在里面找到，本文不讲述关于LeanCloud的使用，知识借助LeanCloud平台举一个在网络上存储数据的例子。

二、使用方法

1.上传数据

AVObject personObject = new AVObject(TABLENAME);
        personObject.put(NAME, person.name);
        personObject.put(AGE, person.age);
        personObject.put(INFO, person.info);
        personObject.saveInBackground(new SaveCallback() {
            @Override
            public void done(AVException e) {
                if (e == null) {
                    Log.v(TAG, "put data success!");
                } else {
                    Log.v(TAG, "put data failed!error:" + e.getMessage());
                }
            }
        });

2. 读取数据

AVQuery<AVObject> avQuery = new AVQuery<>(TABLENAME);
        avQuery.findInBackground(new FindCallback<AVObject>() {
            @Override
            public void done(List<AVObject> list, AVException e) {
                if (e == null) {
                    Log.v(TAG, "get data success!");
                    String message = "";
                    for (int i = 0; i < list.size(); i++) {
                        String name = list.get(i).getString(NAME);
                        int age = list.get(i).getInt(AGE);
                        String info = list.get(i).getString(INFO);

                        message += "name:" + name + ",age:" + age + ",info:" + info + ".\n";
                    }
                    textView.setText(message);
                }
            }
        });

三、小案例

1.添加strings.xml文件

<string name="network">Network</string>
    <string name="get_data">获取数据</string>
    <string name="put_data">上传数据</string>

2.修改activity_main.xml文件

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout     xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.zhangmiao.datastoragedemo.MainActivity">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:text="@string/network" />

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginBottom="@dimen/fab_margin"
            android:layout_marginTop="@dimen/fab_margin"
            android:orientation="horizontal">

            <Button
                android:id="@+id/network_put"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="@string/put_data" />

            <Button
                android:id="@+id/network_get"
                android:layout_width="0dp"
                android:layout_height="wrap_content"
                android:layout_weight="1"
                android:text="@string/get_data" />
        </LinearLayout>

        <TextView
            android:id="@+id/table_info"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="@string/app_name" />
    </LinearLayout>
</android.support.design.widget.CoordinatorLayout>

3.添加NetworkDBManager类

package com.zhangmiao.datastoragedemo;

import android.util.Log;
import android.widget.TextView;

import com.avos.avoscloud.AVException;
import com.avos.avoscloud.AVObject;
import com.avos.avoscloud.AVQuery;
import com.avos.avoscloud.FindCallback;
import com.avos.avoscloud.SaveCallback;

import java.util.List;

/**
 * Created by zhangmiao on 2016/12/22.
 */
public class NetworkDBManager {

    private static final String TAG = "NetworkDBManager";

    private final static String TABLENAME = "person";
    private final static String NAME = "name";
    private final static String AGE = "age";
    private final static String INFO = "info";

    public void putData(Person person) {
        AVObject personObject = new AVObject(TABLENAME);
        personObject.put(NAME, person.name);
        personObject.put(AGE, person.age);
        personObject.put(INFO, person.info);
        personObject.saveInBackground(new SaveCallback() {
            @Override
            public void done(AVException e) {
                if (e == null) {
                    Log.v(TAG, "put data success!");
                } else {
                    Log.v(TAG, "put data failed!error:" + e.getMessage());
                }
            }
        });
    }

    public void getData(final TextView textView) {
        AVQuery<AVObject> avQuery = new AVQuery<>(TABLENAME);
        avQuery.findInBackground(new FindCallback<AVObject>() {
            @Override
            public void done(List<AVObject> list, AVException e) {
                if (e == null) {
                    Log.v(TAG, "get data success!");
                    String message = "";
                    for (int i = 0; i < list.size(); i++) {
                        String name = list.get(i).getString(NAME);
                        int age = list.get(i).getInt(AGE);
                        String info = list.get(i).getString(INFO);

                        message += "name:" + name + ",age:" + age + ",info:" + info + ".\n";
                    }
                    textView.setText(message);
                }
            }
        });
    }
}

4.修改AndroidManifest.xml文件 

<uses-permission android:name="android.permission.INTERNET" />
  <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

5.修改MainActivity

package com.zhangmiao.datastoragedemo;

import android.content.ContentResolver;
import android.content.ContentValues;
import android.database.Cursor;
import android.net.*;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.avos.avoscloud.AVOSCloud;

import java.util.ArrayList;
import java.util.List;


public class MainActivity extends AppCompatActivity implements View.OnClickListener {private NetworkDBManager mNetworkDBManager;

    private TextView mTableInfo;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Log.v("MainActivity", "onCreate");
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        AVOSCloud.initialize(this, "yMNUazdBt872mNtC9aSakjYy-gzGzoHsz", "d4vw3VYdMCjLpsXRhHTBRutC");
        mNetworkDBManager = new NetworkDBManager();

        Button networkGet = (Button) findViewById(R.id.network_get);
        Button networkPut = (Button) findViewById(R.id.network_put);

        mTableInfo = (TextView) findViewById(R.id.table_info);

        networkGet.setOnClickListener(this);
        networkPut.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
        switch (v.getId()) {case R.id.network_put:
                Person person3 = new Person("xiao", 23, "women");
                Person person4 = new Person("zhao", 24, "men");
                mNetworkDBManager.putData(person3);
                mNetworkDBManager.putData(person4);
                break;
            case R.id.network_get:
                mNetworkDBManager.getData(mTableInfo);
                break;
            default:
                Log.v("MainActivity", "default");
                break;
        }
    }
}

 代码下载地址：https://github.com/ZhangMiao147/DataStorageDemo