Android 数据持久化

1.数据库SQLite

处理大量数据以及与数据有关的逻辑时使用

数据库数据文件data/data/packageName/datebases/test.db

platform tools目录 adb, sqlite3

给予权限才能看到.db
adb shell
su -c "chmod 777 /data"
su -c "chmod 777 /data/data"

查看数据文件用sqlite3

SELETE * FROM table;（分号）http://jingyan.baidu.com/article/c843ea0b9bbf1b77931e4ad4.html

2.轻量级处理SharedPreferences

适合app默认配置的保存（初始化时使用）

存

public static void put(Context context, String key, Object object) {
SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sp.edit();

if (object instanceof String) {
editor.putString(key, (String) object);

} else if (object instanceof Integer) {
editor.putInt(key, (Integer) object);

} else if (object instanceof Boolean) {
editor.putBoolean(key, (Boolean) object);

} else if (object instanceof Float) {
editor.putFloat(key, (Float) object);

} else if (object instanceof Long) {
editor.putLong(key, (Long) object);

} else {
editor.putString(key, object.toString());

}
SharedPreferencesCompat.apply(editor);
}

取

public static Object get(Context context, String key, Object defaultObject) {
SharedPreferences sp = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE);
if (defaultObject instanceof String) {
return sp.getString(key, (String) defaultObject);

} else if (defaultObject instanceof Integer) {
return sp.getInt(key, (Integer) defaultObject);

} else if (defaultObject instanceof Boolean) {
return sp.getBoolean(key, (Boolean) defaultObject);

} else if (defaultObject instanceof Float) {
return sp.getFloat(key, (Float) defaultObject);

} else if (defaultObject instanceof Long) {
return sp.getLong(key, (Long) defaultObject);

}
return null;
}

3.ContentProvider

跨应用共享数据和使用系统数据如联系人，图片，视频，音频

//query 获取联系人
ContentResolver contentResolver = this.getContentResolver();
Cursor cursor = contentResolver.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,null,null,null);
if(cursor!=null) {
while (cursor.moveToNext()) {
int index = cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME);
String name = cursor.getString(index);
String phone = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
}
}

4.文件I/O

java.io.FileInputStream和java.io.FileOutputStream这两个类来实现对文件的读写(导出文件使用，不适合做数据交互)

5.网络请求服务器数据

少量涉及安全的数据需要实时获取并保存在服务器