UrlEncoder /Urldecoder
String str = "http://www.baidu.com?serach = 哈哈";
String encode = URLEncoder.encode(str);
System.out.println("encode:" + encode);
//URLDecoder 操作
String decode = URLDecoder.decode(encode);
System.out.println("decode:" + decode);
//URLDecoder一个没有被Encode的数据,会原样打出
String decode2 = URLDecoder.decode(str);
System.out.println("decode:" + decode2);
Base64:byte[]-->string
iv = (ImageView) findViewById(R.id.iv);
findViewById(R.id.btn1).setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
//1.bitmap
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
//2. bitmap-->byte[]
ByteArrayOutputStream baos = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
byte[] byteArray = baos.toByteArray();
//3.byte[]->string,这样就可以用string传给服务器
String bitmapString = Base64.encodeToString(byteArray, Base64.DEFAULT);
System.out.println("bitmapString :" + bitmapString);
//4. string-->byte[];
byte[] bitmapByteArr = Base64.decode(bitmapString, Base64.DEFAULT);
//5.byte[]-->bitmap
Bitmap bitmap2 = BitmapFactory.decodeByteArray(bitmapByteArr, 0, bitmapByteArr.length);
//6.在imageView上设置图片
iv.setImageBitmap(bitmap2);
//obj-->byte[] -->string->sp
}
});
sqlite加密,使用sqlcipher:把lib、assets目录的东西拷进去,但是内存会增加4-5m,需要对数据库加密的时候可以考虑用
MySqliteOpenHelper
public class MySqliteOpenHelper extends SQLiteOpenHelper {
private static String name = "my.db";
private static int version = 1;
public MySqliteOpenHelper(Context context) {
super(context, name, null, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create TABLE t_test(name TEXT,age INTEGER)");
}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
// TODO
}
}
MainActivity
public class MainActivity extends Activity {
private MySqliteOpenHelper helper;
private String password = "xxxxoooo";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SQLiteDatabase.loadLibs(this);//初始化sqlcipher
helper = new MySqliteOpenHelper(this);
}
public void insert(View v) {
//多了个password
SQLiteDatabase db = helper.getWritableDatabase(password);
ContentValues values = new ContentValues();
values.put("name", "billy");
values.put("age", 100);
db.insert("t_test", null, values);
}
public void query(View v) {
SQLiteDatabase db = helper.getReadableDatabase(password);
Cursor c = db.query("t_test", null, null, null, null, null, null);
while (c.moveToNext()) {
String name = c.getString(0);
int age = c.getInt(1);
System.out.println("name:" + name + "age:" + age);
}
}
}
可以作为手机的唯一标识,类似我们pc的机器码;
手机序列号 电池序列号 手机包装序列号
this.PASSWORD = "com.sina.vdisk.security.password.d7af3082d815945ff47ae58647bd9436" + IMEI + appKeyPair.key + appKeyPair.secret;