自定义注解 通过阅读注解类的源码可以发现,任何一个注解类都有如下特征:
注解类会被@interface标记;
注解类的顶部会被@Documented、@Retention、@Target、@Inherited这四个注解标记(@Documented、@Inherited可选,@Retention、@Target必须要有);
注解的作用 格式检查: 告诉编译器信息,比如被@Override标记的方法如果不是父类的某个方法,IDE会报错;
减少配置: 运行时动态处理,得到注解信息,实现代替配置文件的功能;
减少重复工作: 比如第三方框架xUtils,通过注解@ViewInject减少对findViewById的调用,类似的还有(JUnit、ActiveAndroid等);
AndroidAnnotions是一个能够让你快速进行Android开发的开源框架,它能让你专注于真正重要的地方。是代码更加精简,是项目更加容易维护,它的目标是“Fast Android Development.Easy maintainance” Here is a simple example of how your code can dramatically shrink, and become much easier to understand Before
public class BookmarksToClipboardActivity extends Activity {
BookmarkAdapter adapter;
ListView bookmarkList;
EditText search;
BookmarkApplication application;
Animation fadeIn;
//获取系统service的方法(取代原来的clipboardManager = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);)
ClipboardManager clipboardManager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(FLAG_FULLSCREEN, FLAG_FULLSCREEN);
setContentView(R.layout.bookmarks);
bookmarkList = (ListView) findViewById(R.id.bookmarkList);
search = (EditText) findViewById(R.id.search);
application = (BookmarkApplication) getApplication();
fadeIn = AnimationUtils.loadAnimation(this, anim.fade_in);
clipboardManager = (ClipboardManager) getSystemService(CLIPBOARD_SERVICE);
View updateBookmarksButton1 = findViewById(R.id.updateBookmarksButton1);
updateBookmarksButton1.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
updateBookmarksClicked();
}
});
View updateBookmarksButton2 = findViewById(R.id.updateBookmarksButton2);
updateBookmarksButton2.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
updateBookmarksClicked();
}
});
bookmarkList.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> p, View v, int pos, long id) {
Bookmark selectedBookmark = (Bookmark) p.getAdapter().getItem(pos);
bookmarkListItemClicked(selectedBookmark);
}
});
initBookmarkList();
}
void initBookmarkList() {
adapter = new BookmarkAdapter(this);
bookmarkList.setAdapter(adapter);
}
void updateBookmarksClicked() {
UpdateBookmarksTask task = new UpdateBookmarksTask();
task.execute(search.getText().toString(), application.getUserId());
}
private static final String BOOKMARK_URL = //
"http://www.bookmarks.com/bookmarks/{userId}?search={search}";
class UpdateBookmarksTask extends AsyncTask<String, Void, Bookmarks> {
@Override
protected Bookmarks doInBackground(String... params) {
String searchString = params[0];
String userId = params[1];
RestTemplate client = new RestTemplate();
HashMap<String, Object> args = new HashMap<String, Object>();
args.put("search", searchString);
args.put("userId", userId);
HttpHeaders httpHeaders = new HttpHeaders();
HttpEntity<Bookmarks> request = new HttpEntity<Bookmarks>(httpHeaders);
ResponseEntity<Bookmarks> response = client.exchange( //
BOOKMARK_URL, HttpMethod.GET, request, Bookmarks.class, args);
Bookmarks bookmarks = response.getBody();
return bookmarks;
}
@Override
protected void onPostExecute(Bookmarks result) {
adapter.updateBookmarks(result);
bookmarkList.startAnimation(fadeIn);
}
}
void bookmarkListItemClicked(Bookmark selectedBookmark) {
clipboardManager.setText(selectedBookmark.getUrl());
}
}
after
@Fullscreen//全屏
@EActivity(R.layout.bookmarks)// Sets content view to R.layout.translate
@WindowFeature(Window.FEATURE_NO_TITLE)
public class BookmarksToClipboardActivity extends Activity {
BookmarkAdapter adapter;
@ViewById
ListView bookmarkList;
@ViewById
EditText search;
@App
BookmarkApplication application;
@RestService
BookmarkClient restClient;
@AnimationRes // Injects android.R.anim.fade_in
Animation fadeIn;
@SystemService
ClipboardManager clipboardManager;
//因为在onCreate()被调用的时候,@ViewById还没有被set,也就是都为null
//所以如果你要对组件进行一定的初始化,那么你要用@AfterViews注解
@AfterViews
void initBookmarkList() {
adapter = new BookmarkAdapter(this);
bookmarkList.setAdapter(adapter);
}
@Click({R.id.updateBookmarksButton1, R.id.updateBookmarksButton2}) // When R.id.doTranslate button is clicked
void updateBookmarksClicked() {
searchAsync(search.getText().toString(), application.getUserId());
}
@Background // Executed in a background thread
void searchAsync(String searchString, String userId) {
Bookmarks bookmarks = restClient.getBookmarks(searchString, userId);
updateBookmarks(bookmarks);
}
@UiThread // Executed in the ui thread
void updateBookmarks(Bookmarks bookmarks) {
adapter.updateBookmarks(bookmarks);
bookmarkList.startAnimation(fadeIn);
}
@ItemClick
void bookmarkListItemClicked(Bookmark selectedBookmark) {
clipboardManager.setText(selectedBookmark.getUrl());
}
}
// private static final String BOOKMARK_URL = "http://www.bookmarks.com/bookmarks/{userId}?search={search}";
@Rest("http://www.bookmarks.com")
public interface BookmarkClient {
@Get("/bookmarks/{userId}?search={search}")
Bookmarks getBookmarks(@Path String search, @Path String userId);
}