進階三：Android常用框架
OrmLite資料庫框架
常用ORM框架有：
--OrmLite 使用註解，使用簡單
--GreenDAO 自動生成程式碼，效能高
--SugarORM
--Active Android
--Realm
下載OrmLite開發包
http://ormlite.com 下載ormlite-android-x.xx.jar和ormlite-core-x.xx.jar
匯入工程
複製到libs，選中->右鍵->Add As Library
使用
1、建立實體類，添加註解
表前新增
@DatabaseTable[tableName="tb_student"]
欄位前新增
@DatabaseField(generatedId=true)
@DatabaseField(columnName="name",dataType=DataType.STRING,canBeNull=false]
@DatabaseField
2、建立幫助類，繼承OrmLiteSqliteOpenHelper
實現單例模式:
public static synchronized DatabaseHelper getInstance(Context context){
if(sInstance==null){
sInstance=new DatabaseHelper(context);
}
return sInstance;
}
onCreate方法：
TableUtils.createTable(connectionSource,Student.class);//Student為帶註解的實體類名
onUpgrade方法：
TableUtils.dropTable(connectionSrouce,Student.class,true);//true 忽略錯誤
onCreate(sqlLiteDatabase,connectionSrouce);//呼叫onCreate方法重新建立表
3、獲得對應表的Dao類
DatabaseHelper helper=DatabaseHelper.getInstance(this);//獲得DatabaseHelper例項
Dao<Student,Ingteger> stuDao=helper.getDao(Student.class);//獲得表的DAO,泛型：型別、編號
4、執行增刪改查操作
插入資料：
Student stu1=new Student("張三",33,"13300001111");
Student stu2=new Student("李四",23,"13300002222");
Student stu3=new Student("王五,21,"13300003333");
stuDao.create(stu1);
stuDao.createOrUpdate(stu2);
stuDao.createIfNoExists(stu3);
查詢資料：
List<Student> students1=stuDao.queryForAll();
List<Student> students2=stuDao.queryForId(3);
List<Student> students3=stuDao.queryForEq("name","李四");
更新資料：
UpdateBuilder update=stuDao.updateBuilder();
update.setWhere(update.where().eq("phone","13300002222").and().gt("age",20));//gt:大於，lt:小於
update.updateColumnValue("name","小李子");
update.updateColumnValue("phone","13899998888");
update.update();
或
stuDao.updateRaw("update tb_student set name='小張',phone='13844448888' where id=?","1");
刪除資料：
stuDao.deleteById(1);
一對多關係
Student類
...
@DatabaseField(column="school_id",foreign=true,foreignAutoRefresh=true)
private School school;
School類
...
@ForeignCollectionField
private Collection<Student> students;
事務
批量資料操作時，大大提高操作效率。事務是一個整體，要麼全執行，要麼全不執行。
如果把1000條資料放到一個事務裡插入資料庫中。將一次性插入；一條出錯整體不能插入。
DatabaseHelper helper=DatabaseHelper.getInstance(this);
final Dao<Student,Integer> stuDao=helper.getDao(Student.class);
final Student stu=new Student("測試事務",18,"110",new Shool("清華大學","北京"));
TransactionManager.callInTransaction(
helper.getConnectionSource(),
new Callable<Void>(){
@Override
public Void call() throws Exception{
for(int i=0;i<20;i++){
stuDao.create(stu);
if(i==10){
throw new SQLException("test");
}
}
return null;
}
});Okio框架
導包
module,右鍵->Open module settings ->dependencies->新增，搜尋"okio",選擇com.squareup.okio:okio:x.x.x
常用類
ByteString類
建立
okio.ByteString#of(byte...) 輸入位元組，輸出ByteString物件
okio.ByteString#encodeUtf8 輸入字串，輸出ByteString物件
okio.ByteString#decodeHex 輸入16進位制串，輸出ByteString物件
okio.ByteString#decodeBase64 輸入Base64編碼，輸出ByteString物件
okio.ByteString#read 輸入InputStream，輸出ByteString物件
方法
okio.ByteString#base64 返回base64字串
okio.ByteString#hex 返回16進位制的字串
okio.ByteString#md5 返回位元組串的md5值
okio.ByteString#sha1
okio.ByteString#write(java.io.OutputStream)
String str="hello world";
//字串
ByteString byteString= ByteString.encodeUtf8(str);
//16進位制
String hex = byteString.hex();
ByteString byteString2=ByteString.decodeHex(hex);
//Base64編碼
String base64 = byteString.base64();
ByteString byteString3=ByteString.decodeBase64(base64);
//輸入輸出流
FileOutputStream outputStream=new FileOutputStream(file);
byteString3.write(outputStream);
FileInputStream inputStream=new FileInputStream(file);
ByteString byteString4=ByteString.read(inputStream,inputStream.available());
Buffer類
Source介面 輸入流
Sink介面 輸出流
okio.BufferedSource 介面 繼承自 source
okio.BufferedSink 介面 繼承自sink
okio.Buffer buffer=new okio.Buffer();
//讀寫字串
buffer.writeUtf8("hello world");
buffer.readUtf8(1);
//讀寫整數
buffer.writeInt(n);
buffer.readInt();
//輸入輸出流
buffer.readFrom(new FileInputStream("in.png"));
buffer.writeTo(new FileOutputStream("out.png");
//使用source和sink複製檔案，Okio是類
BufferedSource source = Okio.buffer(Okio.source(new File("in.txt")));//連結in.txt檔案
BufferedSink sink=Okio.buffer(Okio.sink(new File("out.txt")));//連結out.txt檔案
source.readAll(sink);//複製OkHttp框架
導包
module,右鍵->Open module settings ->dependencies->新增，搜尋"okhttp",選擇com.squareup.okhttp3:okhttp:x.x.x
使用
public class MainActivity extends AppCompatActivity {
public static final String POST_URL = "https://api.github.com/markdown/raw";
public static final MediaType MEDIA_TYPE_MARKDOWN = MediaType.parse("text/x-markdown; charset=utf-8");
private final OkHttpClient mClient= new OkHttpClient();
private static final String TAG = "MainActivity-xx";
private TextView mTvContent;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTvContent = findViewById(R.id.content_tv);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.actions,menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.menu_get:
get();
break;
case R.id.menu_response:
response();
break;
case R.id.menu_post:
post();
break;
}
return super.onOptionsItemSelected(item);
}
private void post() {
Request.Builder builder = new Request.Builder();
builder.url(POST_URL);
RequestBody requestBody = RequestBody.create(MEDIA_TYPE_MARKDOWN,
"Hello world github/linguist#1 **cool**,and #1!");
builder.post(requestBody);
Request request = builder.build();
Call call = mClient.newCall(request);
call.enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
}
@Override
public void onResponse(Call call, Response response) throws IOException {
if (response.isSuccessful()) {
final String content = response.body().string();
runOnUiThread(new Runnable() {
@Override
public void run() {
mTvContent.setText(content);
}
});
}
}
});
}
private void response() {
Request.Builder builder=new Request.Builder();
builder.url("https://raw.githubusercontent.com/square/okhttp/master/README.md");
Request build = builder.build();
Call call = mClient.newCall(build);
//非同步請求
call.enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
Log.d(TAG, "onFailure() called with: call = [" + call + "], e = [" + e + "]");
}
@Override
public void onResponse(Call call, Response response) throws IOException {
Log.d(TAG, "onResponse() called with: call = [" + call + "], response = [" + response + "]");
if (response.isSuccessful()) {
//Response物件包含Code、Headers、body 三部分
int code = response.code();
Headers headers = response.headers();//map格式
String contentType = headers.get("Content-Type");//獲取header內部資訊
String string = response.body().string();
final StringBuilder stringBuilder=new StringBuilder();
stringBuilder.append("code:"+code);
stringBuilder.append("\n<---分割線--->\nheaders:"+headers);
stringBuilder.append("\n<---分割線--->\nBody:"+string);
runOnUiThread(new Runnable() {
@Override
public void run() {
mTvContent.setText(stringBuilder);
}
});
}
}
});
}
private void get() {
//執行緒池
ExecutorService executor= Executors.newSingleThreadExecutor();
executor.submit(new Runnable() {
@Override
public void run() {
//建立Request物件
Request.Builder builder = new Request.Builder();
builder.url("https://raw.githubusercontent.com/square/okhttp/master/README.md");
Request request = builder.build();
Log.d(TAG, "run: "+request);
//建立Call物件
Call call = mClient.newCall(request);
try {
//同步請求，建立Response物件
Response response = call.execute();
Log.d(TAG, "run: "+response);
//處理資料
if (response.isSuccessful()) {
final String string = response.body().string();
runOnUiThread(new Runnable() {
@Override
public void run() {
mTvContent.setText(string);
}
});
}
} catch (IOException e) {
e.printStackTrace();
}
}
});
executor.shutdown();
}
}picasso框架
強大的圖片下載、型別轉換以及快取管理框架
官網：http://square.github.io/picasso
//使用下載：自動快取的磁碟記憶體或者記憶體快取
Picasso picasso=Picasso.with(MainActivity.this)
.load(mDataUris.get(arg0))//mDataUris.get(arg0)是圖片地址
.setIndicatorsEnabled(true)//設定除錯模式
.resize(100,100)//設定影象大小
.centerCrop//剪下長或寬填充
.rotate(90)//旋轉90度
.placeholder(R.drawable.ic_launcher)//佔位符
.error(R.drawable.ic_launcher)//圖片載入失敗是顯示的圖片
into(icon)//icon是一個ImageView控制元件