感觉现在开始码笔记都是晚上了，练车真是一个耗时的项目。

文本存储

这方面就是JAVA，没什么好讲的，直接上代码。

save()方法

public void save(String inputText) {
	FileOutputStream out = null;
	BufferedWriter writer = null;
	try {
		out = openFileOutput("data", Context.MODE_PRIVATE);
		writer = new BufferedWriter(new OutputStreamWriter(out));
		writer.write(inputText);
	} catch (IOException e) {
		e.printStackTrace();
	} finally {
		try {
			if (writer != null) {
				writer.close();
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

load()方法

public String load() {
	FileInputStream in = null;
	BufferedReader reader = null;
	StringBuilder content = new StringBuilder();
	try {
		in = openFileInput("data");
		reader = new BufferedReader(new InputStreamReader(in));
		String line = "";
		while ((line = reader.readLine()) != null) {
			content.append(line);
		}
	} catch (IOException e) {
		e.printStackTrace();
	} finally {
		if (reader != null) {
			try {
				reader.close();
			} catch (IOException e) {
				e.printStackTrace();
			}
		}
	}
	return content.toString();
}

修改onCreate()方法

APP启动时检测文本文件，如果不为空则读取内容，并且将光标移至文本末尾

protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_main);
	edit = (EditText) findViewById(R.id.edit);
	String inputText = load();
	if (!TextUtils.isEmpty(inputText)) {
		edit.setText(inputText);
		edit.setSelection(inputText.length());
		Toast.makeText(this, "Restoring succeeded", Toast.LENGTH_SHORT).show();
	}
}

onDestroy()方法

在APP关闭时执行save方法保存

protected void onDestroy() {
	super.onDestroy();
	String inputText = edit.getText().toString();
	save(inputText);
}

我真是越来越懒了逃~~记得新建一个EditText控件，巴拉巴拉~~~

SharedPreferences存储

第一次知道还有这种存储方式的，真是孤陋寡闻了，快点码完我去看诛仙了TAT

存储

SharedPreferences.Editor editor = getSharedPreferences("data", MODE_PRIVATE).edit();
editor.putString("name", "Tom");
editor.putInt("age", 28);
editor.putBoolean("married", false);
editor.commit();

会在/data/data/<包名>/shared_prefs中新建一个data.xml的文件，里面的内容是这样的

<?xml version='1.0' encoding='utf-8' standalone='yes' ?>
<map>
    <string name="name">Tom</string>
    <int name="age" value="28" />
    <boolean name="married" value="false" />
</map>

读取

SharedPreferences pref = getSharedPreferences("data", MODE_PRIVATE);
String name = pref.getString("name", "");
int age = pref.getInt("age", 0);
boolean married = pref.getBoolean("married", false);
Log.d("MainActivity", "name is " + name);
Log.d("MainActivity", "age is " + age);
Log.d("MainActivity", "married is " + married);

简洁明白，嗯我先去看诛仙，回来再来码，就这么决定了

SQLite数据库存储

心情不好，继续码笔记

新建数据库

新建一个继承SQLiteOpenHelper的MyDatabaseHelper类

public class MyDatabaseHelper extends SQLiteOpenHelper {
	//创建一个BOOK表
	public static final String CREATE_BOOK = "create table Book ("
			+ "id integer primary key autoincrement, " 
			+ "author text, "
			+ "price real, " 
			+ "pages integer, " 
			+ "name text)";
	//创建一个Category表
	public static final String CREATE_CATEGORY = "create table Category ("
			+ "id integer primary key autoincrement, "
			+ "category_name text, "
			+ "category_code integer)";
	private Context mContext;
//name是数据库名，Factory一般传入null，version是版本号
	public MyDatabaseHelper(Context context, String name,
			CursorFactory factory, int version) {
		super(context, name, factory, version);
		mContext = context;
	}
//执行语句创建数据库，其实你直接输也行
	@Override
	public void onCreate(SQLiteDatabase db) {
		db.execSQL(CREATE_BOOK);
		db.execSQL(CREATE_CATEGORY);
		Toast.makeText(mContext, "Create succeeded", Toast.LENGTH_SHORT).show();
	}
//就是SQL语句
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		db.execSQL("drop table if exists Book");
		db.execSQL("drop table if exists Category");
		onCreate(db);
	}
}

在MainActivity中加入以下代码

dbHelper = new MyDatabaseHelper(this, "BookStore.db", null, 1);
   dbHelper.getWritableDatabase();

插入数据

SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
//开始第一条数据
values.put("name", "The Da Vinci Code");
values.put("author", "Dan Brown");
values.put("pages", 454);
values.put("price", 16.96);
db.insert("Book", null, values);
values.clear();
//开始第二条数据
values.put("name", "The Lost Symbol");
values.put("author", "Dan Brown");
values.put("pages", 510);
values.put("price", 19.95);
db.insert("Book", null, values);

修改数据

SQLiteDatabase db = dbHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("price", 10.99);
db.update("Book", values, "name = ?",
		new String[] { "The Da Vinci Code" });

删除数据

SQLiteDatabase db = dbHelper.getWritableDatabase();
db.delete("Book", "pages > ?", new String[] { "500" });

查询数据

SQLiteDatabase db = dbHelper.getWritableDatabase();
Cursor cursor = db.query("Book", null, null, null, null, null,
		null);
if (cursor.moveToFirst()) {
	do {
		String name = cursor.getString(cursor
				.getColumnIndex("name"));
		String author = cursor.getString(cursor
				.getColumnIndex("author"));
		int pages = cursor.getInt(cursor
				.getColumnIndex("pages"));
		double price = cursor.getDouble(cursor
				.getColumnIndex("price"));
		Log.d("MainActivity", "book name is " + name);
		Log.d("MainActivity", "book author is " + author);
		Log.d("MainActivity", "book pages is " + pages);
		Log.d("MainActivity", "book price is " + price);
	} while (cursor.moveToNext());
}
cursor.close();

直接使用SQL操作数据库

我觉得这种方法简单多了，放几个实例部分代码
创建表

db.execSQL("DROP TABLE IF EXISTS students");  
da.execSQL("CREATE TABLE IF NOT EXISTS student (_id INTEGER PRIMARY KEY AUTOINCREMENT, Name text,Number INTEGER, Chinese INTEGER,Math INTEGER, English integer)");

依据Select编辑框里面内容删除数据

da.execSQL("DELETE FROM student WHERE Name=?",new String[]{Select.getText().toString()});

示例

数据库示例，大一做的，学生成绩管理系统

文本存储
SharedPreferences存储
1. 存储
2. 读取
SQLite数据库存储
示例

Android第一行代码-存储