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
<?xmlversion="1.0"encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<Button
android:id="@+id/save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="保存数据(File)"/>
<Button
android:id="@+id/read"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="读取数据(File)"/>
</LinearLayout>
packagecom.example.yanlei.wifi;
importandroid.os.Bundle;
importandroid.os.Environment;
importandroid.support.v7.app.AppCompatActivity;
importandroid.view.View;
importandroid.view.View.OnClickListener;
importandroid.widget.Button;
importandroid.widget.Toast;
importjava.io.File;
importjava.io.FileInputStream;
importjava.io.FileNotFoundException;
importjava.io.FileOutputStream;
importjava.io.PrintStream;
importjava.util.Scanner;
publicclassMainActivityextendsAppCompatActivity{
privateButtonbtnSave=null;
privateButtonbtnRead=null;
privateFilefile=null;
privatestaticfinalStringFILENAME="data.txt";
@Override
protectedvoidonCreate(BundlesavedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnSave=(Button)super.findViewById(R.id.save);
btnRead=(Button)super.findViewById(R.id.read);
btnSave.setOnClickListener(newOnClickListener(){
publicvoidonClick(Viewv)
{
PrintStreamps=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
Stringpath=Environment.getExternalStorageDirectory().toString()
+File.separator
+"genwoxue"
+File.separator
+FILENAME;
file=newFile(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=newPrintStream(newFileOutputStream(file));
ps.println("跟我学网址：www.genwoxue.com");
ps.println("");
ps.println("电子邮件：hello@genwoxue.com");
}catch(FileNotFoundExceptione){
e.printStackTrace();
}finally{
ps.close();
}
Toast.makeText(getApplicationContext(),"保存成功！",Toast.LENGTH_LONG).show();
}
});
btnRead.setOnClickListener(newOnClickListener(){
publicvoidonClick(Viewv)
{
StringBufferinfo=newStringBuffer();
//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
Stringpath=Environment.getExternalStorageDirectory().toString()
+File.separator
+"genwoxue"
+File.separator
+FILENAME;
file=newFile(path);
if(!file.exists()){
Toast.makeText(getApplicationContext(),"文件不存在！",Toast.LENGTH_LONG).show();
return;
}
//读取文件内容
Scannerscan=null;
try{
scan=newScanner(newFileInputStream(file));
while(scan.hasNext()){
info.append(scan.next()).append("☆☆☆\n");
}
Toast.makeText(getApplicationContext(),info.toString(),Toast.LENGTH_LONG).show();
}catch(FileNotFoundExceptione){
e.printStackTrace();
}finally{
scan.close();
}
}
});
}
}
权限
<?xmlversion="1.0"encoding="utf-8"?> <manifestxmlns:android="http://schemas.android.com/apk/res/android" package="com.example.yanlei.wifi"> <!--在SDCard中创建与删除文件权限--> <uses-permissionandroid:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/> <!--往SDCard写入数据权限--> <uses-permissionandroid:name="android.permission.READ_EXTERNAL_STORAGE"/> <uses-permissionandroid:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:theme="@style/AppTheme"> <activity android:name=".MainActivity" android:label="@string/app_name"> <intent-filter> <actionandroid:name="android.intent.action.MAIN"/> <categoryandroid:name="android.intent.category.LAUNCHER"/> </intent-filter> </activity> </application> </manifest> <uses-permissionandroid:name="android.permission.READ_EXTERNAL_STORAGE"/> <uses-permissionandroid:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
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！