SD卡存储与读写

  1 package com.example.administrator.myapplication.activity;
  2 
  3 import android.os.Bundle;
  4 import android.os.Environment;
  5 import android.support.v7.app.AppCompatActivity;
  6 import android.view.View;
  7 import android.widget.Button;
  8 import android.widget.Toast;
  9 
 10 import com.example.administrator.myapplication.R;
 11 import com.example.administrator.myapplication.entity.SDCard;
 12 
 13 import java.io.File;
 14 import java.io.FileInputStream;
 15 import java.io.FileOutputStream;
 16 import java.io.IOException;
 17 import java.io.ObjectInputStream;
 18 import java.io.ObjectOutputStream;
 19 
 20 public class SdCardActivity extends AppCompatActivity {
 21     Button writeBtn;
 22     Button readBtn;
 23     @Override
 24     protected void onCreate(Bundle savedInstanceState) {
 25         super.onCreate(savedInstanceState);
 26         setContentView(R.layout.activity_sd_card);
 27         inno();
 28     }
 29 
 30     private void inno() {
 31         writeBtn = (Button) findViewById(R.id.write);
 32         writeBtn.setOnClickListener(new View.OnClickListener() {
 33             @Override
 34             public void onClick(View v) {
 35                 WriteToSD();
 36             }
 37         });
 38         readBtn = (Button) findViewById(R.id.read);
 39         readBtn.setOnClickListener(new View.OnClickListener() {
 40             @Override
 41             public void onClick(View v) {
 42                 ReadFormSD();
 43             }
 44         });
 45     }
 46 
 47     //保存文件到SD卡
 48     private void WriteToSD(){
 49         ObjectOutputStream oos = null;
 50         //Environment.getExternalStorageState获取外部存储的状态
 51         String state = Environment.getExternalStorageState();
 52         //外部存储正常  如果SD卡存在
 53         if (state.equals(Environment.MEDIA_MOUNTED)){
 54             //获取外部存储的根路径
 55             File root = Environment.getExternalStorageDirectory();
 56             //在SD卡下创建新的文件夹
 57             File TargetDir = new File(root,super.getPackageName());
 58             //若不存在，创建文件夹
 59             if (!TargetDir.exists()){
 60                 TargetDir.mkdir();
 61             }
 62             try {
 63                 oos = new ObjectOutputStream(new FileOutputStream(new File(TargetDir+"SDCard.txt")));
 64                 SDCard sdCard = new SDCard("小宝","是大二的!");
 65                 oos.writeObject(sdCard);
 66                 Toast.makeText(getApplication(),"写入SD卡成功！",Toast.LENGTH_SHORT).show();
 67             } catch (IOException e) {
 68                 e.printStackTrace();
 69             }finally {
 70                 try {
 71                     oos.flush();
 72                     oos.close();
 73                 } catch (IOException e) {
 74                     e.printStackTrace();
 75                 }
 76             }
 77         }else {
 78             Toast.makeText(getApplication(),"没有找到SD卡",Toast.LENGTH_SHORT).show();
 79         }
 80     }
 81 
 82     //从SD卡读取文件
 83     private void ReadFormSD(){
 84         ObjectInputStream ois = null;
 85         String state = Environment.getExternalStorageState();
 86         if (state.equals(Environment.MEDIA_MOUNTED)){
 87             File root = Environment.getExternalStorageDirectory();
 88             File TargetDir = new File(root,super.getPackageName());
 89             if (TargetDir.exists()){
 90                 try {
 91                     ois = new ObjectInputStream(new FileInputStream(new File(TargetDir+"SDCard.txt")));
 92                     SDCard sdCard = (SDCard) ois.readObject();
 93                     Toast.makeText(SdCardActivity.this,sdCard.getName()+" "+sdCard.getIntroduce(),Toast.LENGTH_SHORT).show();
 94                 } catch (IOException e) {
 95                     e.printStackTrace();
 96                 } catch (ClassNotFoundException e) {
 97                     e.printStackTrace();
 98                 }finally {
 99                     try {
100                         ois.close();
101                     } catch (IOException e) {
102                         e.printStackTrace();
103                     }
104                 }
105             }
106         }
107     }
108 }
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原文地址：https://www.cnblogs.com/xiaolei121/p/6026317.html
SD卡 存储与读写

SD卡存储与读写
