作者:zhaoyunnidaye_260 | 来源:互联网 | 2023-09-10 11:50
(1)目录结构
(2) 布局文件:
(3)保存数据、读取数据的工具类:FileService.java
package com.example.data_storage_interal.file;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.content.Context;
/**
* 使用内部存储的方式,可以使应用卸载的时候清除所有的相关信息
* @author piaodangdehun
*
*/
public class FileService {
private Context context;
public FileService(Context context) {
this.cOntext= context;
}
/**
* 保存内容到文件中
* @param fileName 文件名
* @param mode 模式
* @param data 数据的缓冲区
* @return 返回真假值
*/
public boolean saveContentToFile(String fileName, int mode, byte[] data) {
boolean flag = false;
FileOutputStream outputStream = null;
try {
outputStream = context.openFileOutput(fileName, mode);
try {
outputStream.write(data, 0, data.length);
} catch (IOException e) {
e.printStackTrace();
}
flag = true;
} catch (FileNotFoundException e) {
e.printStackTrace();
} finally {
if (outputStream != null) {
try {
outputStream.close();
} catch (Exception e2) {
}
}
}
return true;
}
/**
* 读取数据
* @param fileName
* @return
*/
public String readContentFromFile(String fileName) {
String result = "";
FileInputStream fileInputStream = null;
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
try {
fileInputStream = context.openFileInput(fileName);
int len = 0;
byte[] data = new byte[1024];
while ((len = fileInputStream.read(data)) != -1) {
outputStream.write(data, 0, len);
}
return new String(outputStream.toByteArray());
} catch (Exception e) {
e.printStackTrace();
}
return "";
}
}
(4)MainActivity.java
package com.example.data_storage_interal;
import com.example.data_storage_interal.file.FileService;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends Activity {
private Button button;
private EditText editText;
private FileService fileService;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) this.findViewById(R.id.button1);
editText = (EditText) this.findViewById(R.id.editText1);
fileService = new FileService(this);
/*
* 按钮点击的时候存放到文件中
*/
button.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
String valueString = editText.getText().toString().trim();
boolean flag = fileService.saveContentToFile("bb.txt",
Context.MODE_APPEND, valueString.getBytes());
if (flag) {
Toast.makeText(MainActivity.this, "保存成功!",
Toast.LENGTH_SHORT).show();
}
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
(5)测试类(要在资源文件中添加相应的信息、这里不说)
package com.example.data_storage_interal;
import com.example.data_storage_interal.file.FileService;
import android.app.Service;
import android.content.Context;
import android.test.AndroidTestCase;
import android.util.Log;
public class MyTest extends AndroidTestCase {
private static final String TAG = "MyTest";
/*
* 保存数据
*/
public void save() {
FileService fileService = new FileService(getContext());
boolean flag = fileService.saveContentToFile("aa.txt",
Context.MODE_PRIVATE + Context.MODE_APPEND, "nihao".getBytes());
Log.i(TAG, "--->>" + flag);
}
/*
* 保存数据
*/
public void read() {
FileService fileService = new FileService(getContext());
String msg = fileService.readContentFromFile("bb.txt");
Log.i(TAG, "--->>" + msg);
}
}
保存成功后会在data-data-apk的安装目录下找到相应的文件:
Android学习笔记之数据的内部存储方式实习数据的读写