1.文件(Files)
2.SharedPreferences
3.SQLite数据库
4.ContentProvider
5.网络

image.png

image.png

openFileOutPut方法的第二参数用于指定操作模式，四种模式：

image.png

SharedPrefrernces

image.png

···
package com.example.filetext;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;

public class MainActivity extends Activity {
private Context mComtext;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mComtext = MainActivity.this;
try {
FileOutputStream openFileOutput = mComtext.openFileOutput("111.txt", MODE_APPEND);
openFileOutput.write("123456！".getBytes());
openFileOutput.close();
//
FileInputStream openFileInput = mComtext.openFileInput("111.txt");
byte [] b=new byte[1024];
int read = openFileInput.read(b);
Log.e("TAG", "read----->"+new String(b,0,read));
} catch (Exception e) {
e.printStackTrace();
}

    //获取file目录的路径
    
    File filesDir = getFilesDir();//获取应用包名下的file目录
    
    File cacheDir = getCacheDir();//获取应用包名下的cache目录
    File ed = Environment.getExternalStorageDirectory();//SD卡路径
       Log.e("TAG", filesDir.getPath());
       Log.e("TAG", cacheDir.getPath());
       Log.e("TAG", ed.getPath());
       
       //使用SD卡之前先判断是否挂载
       if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            File sd = Environment.getExternalStorageDirectory();
            File file = new File(sd,"t12.txt");
           
        try {
            file.createNewFile();
            
            FileOutputStream fos = new FileOutputStream(file);
            fos.write("456".getBytes());
            fos.close();
            
            FileInputStream fis = new FileInputStream(file);
            byte b[]= new byte [1024];
            int read = fis.read(b);
            Log.e("TAG", "------>"+new String(b,0,read));
           
        
        } catch (IOException e) {
            e.printStackTrace();
            Log.d("sss",e.getMessage());
        }
        
    }
       findViewById(R.id.btn1).setOnClickListener(new OnClickListener() {
        
        @Override
        public void onClick(View v) {
             //1.创建shareprefercens对象
            SharedPreferences sp = getSharedPreferences("info", MODE_PRIVATE);
            //2.获取sp的编辑器
            Editor edit = sp.edit();
            //3.使用edit存储数据
            edit.putString("name", "zhangsan");
            edit.putInt("age", 18);
            edit.putBoolean("sex", true);
            //4.提交
            edit.commit();
            
            
        }
    });
       
       findViewById(R.id.btn2).setOnClickListener(new OnClickListener() {
        
        @Override
        public void onClick(View v) {
            //1.创建shareprefercens对象
            SharedPreferences sp = getSharedPreferences("info", MODE_PRIVATE);
            
            //2.获取数据
            String string = sp.getString("name", "11");
            Log.e("TAG", string);
        }
    });
       
    
}

}

···