1.知识图谱：
XML代码：
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout
- xmlns:android="http://schemas.android.com/apk/res/android"
- xmlns:app="http://schemas.android.com/apk/res-auto"
- xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
- android:layout_height="match_parent"
- android:orientation="vertical"
- tools:context="com.example.cookie.android0623data.MainActivity">
- <EditText
- android:layout_width="match_parent"
- android:layout_height="wrap_content"
- android:id="@+id/et_main_name"
- android:hint="请输入用户名"/>
- <EditText
- android:layout_width="match_parent"
- android:layout_height="wrap_content"
- android:lines="5"
- android:id="@+id/et_main_text"/>
- <LinearLayout
- android:layout_width="match_parent"
- android:layout_height="wrap_content"
- android:orientation="vertical">
- <Button
- android:layout_width="match_parent"
- android:layout_height="wrap_content"
- android:text="保存"
- android:onClick="save"/>
- <Button
- android:layout_width="match_parent"
- android:layout_height="wrap_content"
- android:text="打开"
- android:onClick="read"/>
- </LinearLayout>
- </LinearLayout>
Java代码：
- package com.example.cookie.android0623data;
- import android.content.Context;
- import android.os.Environment;
- import android.support.v7.app.AppCompatActivity;
- import android.os.Bundle;
- import android.view.View;
- import android.widget.EditText;
- import android.widget.Toast;
- import java.io.FileInputStream;
- import java.io.FileNotFoundException;
- import java.io.FileOutputStream;
- import java.io.IOException;
- public class MainActivity extends AppCompatActivity {
- private EditText et_main_text;
- private EditText et_main_name;
- private String sdCard;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.activity_main);
- et_main_text = (EditText) findViewById(R.id.et_main_text);
- et_main_name = (EditText) findViewById(R.id.et_main_name);
- //获取手机内存卡的路径
- if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){
- sdCard = Environment.getExternalStorageDirectory().getAbsolutePath();
- }
- }
- public void save(View view){
- String content=et_main_text.getText().toString();
- String fileName=et_main_name.getText().toString();
- //存东西，输出流OutputStream
- try {
- //存储在手机内存里面
- //FileOutputStream fos=openFileOutput(fileName, Context.MODE_PRIVATE);
- //存储在内存卡里面
- FileOutputStream fos=new FileOutputStream(sdCard+"/"+fileName);
- fos.write(content.getBytes());
- fos.close();
- Toast.makeText(this, "保存成功！", Toast.LENGTH_SHORT).show();
- } catch (FileNotFoundException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- public void read(View view){
- String fileName=et_main_name.getText().toString();
- //读，输入流Input
- try {
- //存储在手机内存里
- // FileInputStream fis= openFileInput(fileName);
- //存储在手机内存卡里面
- FileInputStream fis=new FileInputStream(sdCard+"/"+fileName);
- byte buf[]=new byte[1024];
- int len=0;
- StringBuffer s=new StringBuffer();
- while((len=fis.read(buf))!=-1){
- s.append(new String(buf,0,len));
- }
- et_main_text.setText(s);
- fis.close();
- } catch (FileNotFoundException e) {
- e.printStackTrace();
- } catch (IOException e) {
- e.printStackTrace();
- }
- }
- <span style="font-size:14px;"><strong>}</strong></span>
存储在手机内存卡里面要在manifests下的AndroidManifest.xml里面给权限：
- <!-- 内存卡读和写的权限 -->
- <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
- <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
存储在手机内存里面的查看文件的路径是：
在夜神模拟器里面的查看是：文件管理------》data--------->data---------->项目的包名------------》files-------------->文件名
存储在手机内存卡里面查看文件的路径是：
文件管理------>mnt---------->sdcard---------->文件名