一个非常小型的Kotlin项目，但是该有的都有。如果您觉得有意思就帮我star下，人多了我就会放更多的福利哦。github
先上福利。Release1.0
特点
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快速跳转至顶部，底部，指定位置。
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设置壁纸。
离线缓存。
组成
语言：Kotlin，Java
网络请求：HttpUrlConnection
数据库：Sqlite
数据源：Jsoup
第三方库：Glide
概述
1) 网络请求
网络框架并没有使用RxRetrofit等，为了保证精简高效直接使用的HttpUrlConnection
get
val request = AsyncNetwork()
request.request(Constants.HOST_MOBILE_URL, null)
request.setRequestCallback(object : IRequestCallback {
override fun onSuccess(httpURLConnection: HttpURLConnection?, response: String) {
//todo
}
})post
val request = AsyncNetwork()
request.request(Constants.HOST_MOBILE_URL, mutableMapOf())
request.setRequestCallback(object : IRequestCallback {
override fun onSuccess(httpURLConnection: HttpURLConnection?, response: String) {
//todo
}
})2) 数据库
数据库没有使用第三方框架，直接使用的sql语句。
CREATE TABLE tb_class_page_list (
_id INTEGER PRIMARY KEY ASC AUTOINCREMENT,
href STRING UNIQUE,
description STRING,
image_url STRING,
id_class_page INTEGER REFERENCES tb_class_page (_id) ON DELETE CASCADE ON UPDATE CASCADE,
[index] INTEGER);3) 读写缓存
Serializable的效率远低于Parcelable，所以采用Parcelable实现的缓存机制，速度快了大概7，8倍。
读取缓存
val helper = PageListCacheHelper(container?.context?.filesDir?.absolutePath)
val pageModel: Any? = helper.get(key)写入缓存
val helper = PageListCacheHelper(context.filesDir.absolutePath)
helper.put(key, object)删除缓存
val helper = PageListCacheHelper(context.filesDir.absolutePath)
helper.remove(key)4) jsoup获取数据
由于数据是用从html页面中提取的，所以速度偏慢，为了不影响体验做了一套缓存机制，来做到流畅体验。
Document doc = Jsoup.parse(html);
Elements elements = body.getElementsByTag("a");
String text = elements.get(0).text();
String imageUrl = elements.get(0).attr("src");
...5) 组件
-
Activity fragment替代activity来显示新界面
因为activity需要在Manifiest中注册，所以当有多个activity的时候，就需要编写很长的Manifiest文件，严重影响了Manifiest的可读性，界面的风格也比较笨重。所以一个新页面就注册一个activity不太合适，我们通过用activity做为容器添加不同的Fragment来达到注册一个activity启动多个不同页面的效果。生命周期由activity管理，更方便简洁。
open class BaseFragmentActivity : BaseActionActivity() { companion object { private const val EXTRA_FRAGMENT_NAME = "extra_fragment_name" private const val EXTRA_FRAGMENT_ARG = "extra_fragment_arguments" @JvmOverloads @JvmStatic fun newInstance(context: Context, fragment: Class<*>, bundle: Bundle? = null, clazz: Class= getActivityClazz()): Intent { val intent = Intent(context, clazz) intent.putExtra(EXTRA_FRAGMENT_NAME, fragment.name) intent.putExtra(EXTRA_FRAGMENT_ARG, bundle) return intent } protected open fun getActivityClazz(): Class { return BaseFragmentActivity::class.java } } override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.cc_activity_base_fragment) val fragmentName = intent.getStringExtra(EXTRA_FRAGMENT_NAME) var fragment: Fragment? = null if (TextUtils.isEmpty(fragmentName)) { //set default fragment //fragment = makeFragment(MainFragment::class.java!!.getName()) } else { val args = intent.getBundleExtra(EXTRA_FRAGMENT_ARG) try { fragment = makeFragment(fragmentName) if (args != null) fragment?.arguments = args } catch (e: Exception) { e.printStackTrace() } } if (fragment == null) return supportFragmentManager .beginTransaction() .replace(R.id.fragment_container, fragment) .commit() } fun makeFragment(name: String): Fragment? { try { val fragmentClazz = Class.forName(name) return fragmentClazz.newInstance() as Fragment } catch (e: Exception) { e.printStackTrace() } return null } }
6) 序列化性能
性能测试，Serializable VS Externalizable，为了避免干扰，我们使用AndroidTest进行测试。
模型
class Model1 implements Serializable {
String text;
int code;
boolean bool;
Model1 child;
}
class Model2 extends Model1 implements Externalizable {
public Model2() {
}
@Override
public void readExternal(ObjectInput input) throws IOException, ClassNotFoundException {
text = input.readUTF();
code = input.readInt();
bool = input.readBoolean();
child = new Model2();
child.text = input.readUTF();
child.code = input.readInt();
child.bool = input.readBoolean();
}
@Override
public void writeExternal(ObjectOutput output) throws IOException {
output.writeUTF(text);
output.writeInt(code);
output.writeBoolean(bool);
if (child != null) {
output.writeUTF(child.text);
output.writeInt(child.code);
output.writeBoolean(child.bool);
}
}
}测试
@Test
public void serializableVSExternalizable() throws Exception {
List testModel1 = new ArrayList<>();
for (int i = 0; i < 50000; i++) {
Model1 model1 = new Model1();
model1.text = "Hello World " + i;
model1.code = i;
model1.bool = false;
Model1 child = new Model1();
child.text = "Hello World Child" + i;
child.code = i;
child.bool = false;
model1.child = child;
testModel1.add(model1);
}
long startTime = System.currentTimeMillis();
File file = new File("/sdcard/serializable");
ObjectOutputStream oStream = new ObjectOutputStream(new FileOutputStream(file));
oStream.writeObject(testModel1);
oStream.close();
Log.e("serializable", "write time " + (System.currentTimeMillis() - startTime));
startTime = System.currentTimeMillis();
ObjectInputStream iStream = new ObjectInputStream(new FileInputStream(file));
testModel1 = (List) iStream.readObject();
iStream.close();
Log.e("serializable", "read time " + (System.currentTimeMillis() - startTime));
testModel1 = null;
List testModel2 = new ArrayList<>();
for (int i = 0; i < 50000; i++) {
Model2 model2 = new Model2();
model2.text = "Hello World " + i;
model2.code = i;
model2.bool = false;
Model2 child = new Model2();
child.text = "Hello World Child" + i;
child.code = i;
child.bool = false;
model2.child = child;
testModel2.add(model2);
}
startTime = System.currentTimeMillis();
file = new File("/sdcard/externalizable");
oStream = new ObjectOutputStream(new FileOutputStream(file));
oStream.writeObject(testModel2);
oStream.close();
Log.e("externalizable", "write time " + (System.currentTimeMillis() - startTime));
startTime = System.currentTimeMillis();
iStream = new ObjectInputStream(new FileInputStream(file));
testModel2 = (List) iStream.readObject();
iStream.close();
Log.e("externalizable", "read time " + (System.currentTimeMillis() - startTime));
} 结果
序列化5000个对象
Serializable：写入耗时4026 ms，读取耗时177 ms
Externalizable：写入耗时2680 ms，读取耗时79 ms
序列化50000个对象
Serializable：写入耗时46872 ms，读取耗时1807 ms
Externalizable：写入耗时41334 ms，读取耗时792 ms从结果上可以看到Externalizalbe相比于Serializable是稍微快一些点不管是写入还是读取速度。对象存储还可以使用一些对象关系映射（ORM）型的数据库。如GreenDao等等。
7) Java中的深拷贝
由于System.arrayCopy()该方法拷贝数组的时候，如果是基本数据类型则是深拷贝，如果是对象类型则会是浅拷贝，无法做到深拷贝，所以想深拷贝一个数组就得循环创建对象并赋值，这显得很麻烦。所以项目中使用序列化的方法进行深拷贝。PS：Serializable序列化方式读取的时候并不会调用对象构造方法，而Externalizable序列化方式读取时会调用对象的无参构造方法。
@SuppressWarnings("unchecked")
public static T deepCopyOrThrow(T src) throws IOException, ClassNotFoundException {
ByteArrayOutputStream byteOut = new ByteArrayOutputStream();
ObjectOutputStream out = new ObjectOutputStream(byteOut);
out.writeObject(src);
ByteArrayInputStream byteIn = new ByteArrayInputStream(byteOut.toByteArray());
ObjectInputStream in = new ObjectInputStream(byteIn);
return (T) in.readObject();
}
public static T deepCopy(T src) {
try {
return deepCopyOrThrow(src);
} catch (Exception ignore) {
ignore.printStackTrace();
return null;
}
}