Android 数据库文件存取至储存卡的方法

废话不多说了，直接给大家贴代码了，具体代码如下

 

package com.example.yanlei.wifi;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.PrintStream;
import java.util.Scanner;
public class MainActivity extends AppCompatActivity {
private Button btnSave=null;
private Button btnRead=null;
private File file=null;
private static final String FILENAME="data.txt";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnSave=(Button)super.findViewById(R.id.save);
btnRead=(Button)super.findViewById(R.id.read);

btnSave.setOnClickListener(new OnClickListener(){
public void onClick(View v)
{
PrintStream ps=null;

//判断外部存储卡是否存在
if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
Toast.makeText(getApplicationContext(), "读取失败，SD存储卡不存在！", Toast.LENGTH_LONG).show();
return;
}
//初始化File
String path=Environment.getExternalStorageDirectory().toString()
+File.separator
+"genwoxue"
+File.separator
+FILENAME;
file=new File(path);

//如果当前文件的父文件夹不存在，则创建genwoxue文件夹
if(!file.getParentFile().exists())
file.getParentFile().mkdirs();
//写文件
try {
ps = new PrintStream(new FileOutputStream(file));
ps.println("跟我学网址：www.genwoxue.com");
ps.println("");
ps.println("电子邮件：[email protected]");
} catch (FileNotFoundException e) {
e.printStackTrace();
}finally{
ps.close();
}
Toast.makeText(getApplicationContext(), "保存成功！", Toast.LENGTH_LONG).show();
}
});
btnRead.setOnClickListener(new OnClickListener(){
public void onClick(View v)
{
StringBuffer info=new StringBuffer();

//判断外部存储卡是否存在
if(!Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
Toast.makeText(getApplicationContext(), "读取失败，SD存储卡不存在！", Toast.LENGTH_LONG).show();
return;
}
//初始化File
String path=Environment.getExternalStorageDirectory().toString()
+File.separator
+"genwoxue"
+File.separator
+FILENAME;
file=new File(path);

if(!file.exists()){
Toast.makeText(getApplicationContext(), "文件不存在！", Toast.LENGTH_LONG).show();
return;
}
//读取文件内容
Scanner scan=null;
try {
scan=new Scanner(new FileInputStream(file));
while(scan.hasNext()){
info.append(scan.next()).append("☆☆☆\n");
}
Toast.makeText(getApplicationContext(), info.toString(), Toast.LENGTH_LONG).show();
} catch (FileNotFoundException e) {
e.printStackTrace();
}finally{
scan.close();
}
}
});
}
}

权限

以上所述是小编给大家介绍的Android 数据库文件存取至储存卡的方法，希望对大家有所帮助，本文写的不好还请各位大侠见谅！