我的 Android 之旅（十九）---数据存储--向SD卡中以实体类的方式存取数据

首先先新建一个实体类：

package com.jerehedu.jreduch04.entity;

import java.io.Serializable;

/**
 * Created by on 0162016/8/16.
 */
public class News implements Serializable{
    private Boolean listShow;
    private String size;
    private Boolean notice;
    private Boolean components;
    private Boolean read;
    private Boolean replay;

    public News() {
    }

    public News(Boolean listShow, String size, Boolean notice, Boolean components, Boolean read, Boolean replay) {
        this.listShow = listShow;
        this.size = size;
        this.notice = notice;
        this.components = components;
        this.read = read;
        this.replay = replay;
    }

    public Boolean getListShow() {
        return listShow;
    }

    public void setListShow(Boolean listShow) {
        this.listShow = listShow;
    }

    public String getSize() {
        return size;
    }

    public void setSize(String size) {
        this.size = size;
    }

    public Boolean getNotice() {
        return notice;
    }

    public void setNotice(Boolean notice) {
        this.notice = notice;
    }

    public Boolean getComponents() {
        return components;
    }

    public void setComponents(Boolean components) {
        this.components = components;
    }

    public Boolean getRead() {
        return read;
    }

    public void setRead(Boolean read) {
        this.read = read;
    }

    public Boolean getReplay() {
        return replay;
    }

    public void setReplay(Boolean replay) {
        this.replay = replay;
    }
}

 

对于该类来说，需要序列化推荐使用Serializable

实现序列化的方法

Android中实现序列化有两个选择：一是实现Serializable接口（是JavaSE本身就支持的），一是实现Parcelable接口（是Android特有功能，效率比实现Serializable接口高效，可用于Intent数据传递，也可以用于进程间通信（IPC））。实现Serializable接口非常简单，声明一下就可以了，而实现Parcelable接口稍微复杂一些，但效率更高，推荐用这种方法提高性能。

在主函数中，首先先从实体类里获取数据，利用get方法获得原有的数据，

若存储在SD卡中，首先判断SD卡的状态，然后获取SD卡的根目录

.xml文件中的代码：

package com.jerehedu.jreduch04;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.CheckBox;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.jerehedu.jreduch04.entity.News;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.StreamCorruptedException;

public class Save2Activity extends AppCompatActivity {
private Button finish;
    private CheckBox c1,c2,c3,c4,c5;
    private TextView textSize;
    private LinearLayout ll;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_srcoll__view_to_card);
        finish= (Button) findViewById(R.id.finish);
        c1= (CheckBox) findViewById(R.id.c1);
        c2= (CheckBox) findViewById(R.id.c2);
        c3= (CheckBox) findViewById(R.id.c3);
        c4= (CheckBox) findViewById(R.id.c4);
        c5= (CheckBox) findViewById(R.id.c5);
        ll= (LinearLayout) findViewById(R.id.ll);
        textSize= (TextView) findViewById(R.id.textSize);
        readSetting();
        //设置保存文件
        ll.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                AlertDialog.Builder builder=new AlertDialog.Builder(Save2Activity.this);
       builder.setTitle("请选择");
       builder.setIcon(R.mipmap.ic_launcher);
       final String[] items={"大","中","小"};
        int i;
       for ( i=0;i<items.length;i++){
            if (items[i].equals(textSize.getText())){
               break;
           }
        }
       builder.setSingleChoiceItems(items,i , new DialogInterface.OnClickListener() {
            @Override
           public void onClick(DialogInterface dialog, int i) {
               Toast.makeText(getBaseContext(), items[i].toString(), Toast.LENGTH_SHORT).show();
                textSize.setText(items[i].toString());
               dialog.dismiss();

            }
        });
        AlertDialog alertDialog=builder.create();
       alertDialog.show();
            }
        });


       finish.setOnClickListener(new View.OnClickListener() {
           @Override
           public void onClick(View v) {
               News news = new News();
               news.setListShow(c1.isChecked());
               news.setSize(textSize.getText().toString());
               news.setNotice(c2.isChecked());
               news.setComponents(c3.isChecked());
               news.setRead(c4.isChecked());
               news.setReplay(c5.isChecked());
               String state = Environment.getExternalStorageState();
               if (!state.equals(Environment.MEDIA_MOUNTED)) {
                   Toast.makeText(Save2Activity.this, "SD卡未就绪", Toast.LENGTH_SHORT).show();
                   return;
               }
               File root = Environment.getExternalStorageDirectory();
               FileOutputStream fos = null;
               ObjectOutputStream oos = null;
               try {
                   fos = new FileOutputStream(root + "/settings.txt");
                   oos = new ObjectOutputStream(fos);
                   oos.writeObject(news);
                   Toast.makeText(Save2Activity.this, "保存成功", Toast.LENGTH_SHORT).show();
               } catch (FileNotFoundException e) {
                   e.printStackTrace();
               } catch (IOException e) {
                   e.printStackTrace();
               } finally {
                   if (oos != null) {
                       try {
                           oos.close();
                       } catch (IOException e) {
                           e.printStackTrace();
                       }
                   }
               }

           }
       });

    }



   public void readSetting(){
       File root=Environment.getExternalStorageDirectory();
       FileInputStream fis=null;
       ObjectInputStream ois=null;
       try {
           fis=new FileInputStream(root+"/settings.txt");
           ois=new ObjectInputStream(fis);
           News news= (News) ois.readObject();
          textSize.setText(news.getSize());
          c1.setChecked(news.getListShow());
          c2.setChecked(news.getComponents());
          c3.setChecked(news.getNotice());
          c4.setChecked(news.getRead());
          c5.setChecked(news.getReplay());
       } catch (FileNotFoundException e) {
           e.printStackTrace();
       } catch (StreamCorruptedException e) {
           e.printStackTrace();
       } catch (IOException e) {
           e.printStackTrace();
       } catch (ClassNotFoundException e) {
           e.printStackTrace();
       }finally {
           if (ois!=null){
               try {
                   ois.close();
               } catch (IOException e) {
                   e.printStackTrace();
               }
           }
       }

   }
}

布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    tools:context="com.jerehedu.jreduch04.ScrollView_VerticalActivity">
    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="none"
        android:id="@+id/sv">
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:orientation="vertical">
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal">
                <ImageView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:src="@mipmap/p1"
                    android:id="@+id/iv1"/>
                <TextView
                    android:layout_width="200dp"
                    android:layout_height="wrap_content"
                    android:text="设置"
                    android:gravity="center"
                    android:textSize="25sp"/>
                <Button
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="完成"
                    android:textSize="20sp"
                    android:id="@+id/finish"
                    />
            </LinearLayout>
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:paddingTop="10dp">
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="列表显示摘要"
                    android:textSize="24sp"
                    android:gravity="center"
                    android:id="@+id/listShow"
                    android:layout_weight="1"
                    />
                <CheckBox
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="150dp"
                    android:layout_gravity="center"
                    android:id="@+id/c1"

                    />
            </LinearLayout>
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:paddingTop="10dp"
                android:orientation="horizontal"
                android:id="@+id/ll"
              >
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="字体大小"
                    android:textSize="24sp"
                    android:id="@+id/size"
                    android:layout_weight="1"/>
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:textSize="24sp"
                    android:id="@+id/textSize"
                   />
            </LinearLayout>
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
               >
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="列表页评论"
                    android:textSize="24sp"
                    android:gravity="center"
                    android:layout_weight="1"/>
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="不限"
                    android:textSize="20sp"
                    android:layout_marginLeft="160dp"

                    />
            </LinearLayout>
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="2G/3G网络流量"
                    android:textSize="24sp"
                    android:gravity="center"
                    android:layout_weight="1"/>
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="控制流量"
                    android:textSize="20sp"
                    android:layout_marginLeft="100dp"

                    />
            </LinearLayout>
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content">
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="清理缓存"
                    android:textSize="24sp"
                    android:gravity="center"
                    android:layout_weight="1"/>
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="当前缓存2.4MB"
                    android:textSize="20sp"
                    android:layout_marginLeft="100dp"
                    />
            </LinearLayout>
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:paddingTop="10dp">
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="推送通知"
                    android:textSize="24sp"
                    android:gravity="center"
                    android:id="@+id/notice"
                    android:layout_weight="1"
                    />
                <CheckBox
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="200dp"
                    android:layout_gravity="center"
                    android:id="@+id/c2"
                    />
            </LinearLayout>
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:paddingTop="10dp">
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="互动插件"
                    android:textSize="24sp"
                    android:gravity="center"
                    android:id="@+id/components"
                    android:layout_weight="1"
                    />
                <CheckBox
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="200dp"
                    android:layout_gravity="center"
                    android:id="@+id/c3"
                    />
            </LinearLayout>
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:paddingTop="10dp">
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="自动优化阅读"
                    android:textSize="24sp"
                    android:gravity="center"
                    android:id="@+id/read"
                    android:layout_weight="1"/>
                <CheckBox
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="150dp"
                    android:layout_gravity="center"
                    android:id="@+id/c4"
                    />
            </LinearLayout>
            <View
                android:layout_width="match_parent"
                android:layout_height="1dp"
                android:background="#000">
            </View>
            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal"
                android:paddingTop="10dp">
                <TextView
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:text="收藏时转发"
                    android:textSize="24sp"
                    android:gravity="center"
                    android:id="@+id/replay"
                    />
                <CheckBox
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_marginLeft="175dp"
                    android:layout_gravity="center"
                    android:id="@+id/c5"
                    />
            </LinearLayout>

        </LinearLayout>
    </ScrollView>

</LinearLayout>

运行结果如下：

在该布局中可以对单选框进行操作，也可以更改字体大小：

选择完成后点击保存按钮，实现数据的保存：

当退出该程序后重新进入后，仍然保持当时所选的界面：