前言：
App項目開發大部分時候還是以UI頁面為主，這時我們需要調用大量的findViewById以及setOnClickListener等代碼，控件的少的時候我們還能接受，控件多起來有時候就會有一種想砸鍵盤的沖動。所以這個時候我們想著可以借助注解的方式讓我們從這種繁重的工作中脫離出來，也讓代碼變得更加簡潔，便于維護，今天主要學習一下只專注View、Resource、Action注解框架BufferKnife 。
BufferKnife 介紹
BufferKnife 是一個專注于Android系統的View、Resource、Action注入框架。官網：http://jakewharton.github.io/butterknife/gitHub：https://github.com/JakeWharton/butterknife/BufferKnife 使用前后對比：
看看沒有使用View注解之前我們是如何做的① 使用之前
public class ExampleActivity extends AppCompatActivity { PRivate final static String TAG = ExampleActivity.class.getSimpleName(); String butterKnifeStr; Drawable butterKnifeDrawable; Button butterKnifeBtn; ImageView butterKnifeIv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_butter_knife); initResource(); initViews(); } private void initViews() { butterKnifeBtn = (Button) findViewById(R.id.btn_butter_knife); butterKnifeBtn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Log.e(TAG, "onButterKnifeBtnClick"); } }); butterKnifeIv = (ImageView) findViewById(R.id.iv_butter_knife); butterKnifeBtn.setText(butterKnifeStr); butterKnifeIv.setImageDrawable(butterKnifeDrawable); } private void initResource() { butterKnifeStr = getString(R.string.title_btn_butter_knife); butterKnifeDrawable = getDrawable(R.mipmap.ic_launcher); }}② 使用之后
public class ButterKnifeActivity extends AppCompatActivity { private final static String TAG = ButterKnifeActivity.class.getSimpleName(); private Unbinder unbinder; @BindString(R.string.title_btn_butter_knife) String butterKnifeStr; @BindDrawable(R.mipmap.ic_launcher) Drawable butterKnifeDrawable; @BindView(R.id.btn_butter_knife) Button butterKnifeBtn; @BindView(R.id.iv_butter_knife) ImageView butterKnifeIv; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_butter_knife); unbinder = ButterKnife.bind(this); initViews(); } private void initViews() { butterKnifeBtn.setText(butterKnifeStr); butterKnifeIv.setImageDrawable(butterKnifeDrawable); } @OnClick(R.id.btn_butter_knife) public void onButterKnifeBtnClick(View view) { Log.e(TAG, "onButterKnifeBtnClick"); } @Override protected void onDestroy() { super.onDestroy(); unbinder.unbind(); }}③ ButterKnife 優勢
通過上面使用前后對比來分析下ButterKnife優勢
強大的View綁定和Click事件處理功能，簡化代碼，提升開發效率方便的處理Adapter里的ViewHolder綁定問題運行時不會影響APP效率，使用配置方便代碼清晰，可讀性強使用前后對比之后有沒有覺得非常的簡單易用。接下來來看下具體怎么使用的？
BufferKnife 如何使用：
① 照著官網(在Github有) 添加依賴
② 注入和重置注入
Activity
class ExampleActivity extends Activity { @BindView(R.id.title) TextView title; @BindView(R.id.subtitle) TextView subtitle; @BindView(R.id.footer) TextView footer; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.simple_activity); ButterKnife.bind(this); // 這句話要在setContentView之下,否則會找不到組件 // TODO Use fields... }}Fragment：由于不同的視圖生命周期，所以需要在onCreateView bind，在onDestroyView unbind
public class FancyFragment extends Fragment { @BindView(R.id.button1) Button button1; @BindView(R.id.button2) Button button2; private Unbinder unbinder; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fancy_fragment, container, false); unbinder = ButterKnife.bind(this, view); // TODO Use fields... return view; } @Override public void onDestroyView() { super.onDestroyView(); unbinder.unbind(); }}ViewHolder
public class MyAdapter extends BaseAdapter { @Override public View getView(int position, View view, ViewGroup parent) { ViewHolder holder; if (view != null) { holder = (ViewHolder) view.getTag(); } else { view = inflater.inflate(R.layout.whatever, parent, false); holder = new ViewHolder(view); view.setTag(holder); } holder.name.setText("John Doe"); // etc... return view; } static class ViewHolder { @BindView(R.id.title) TextView name; @BindView(R.id.job_title) TextView jobTitle; public ViewHolder(View view) { ButterKnife.bind(this, view); } }}view注入 @BindView，@BindViews
@BindView(R.id.btn_butter_knife) Button butterKnifeBtn; @BindViews({R.id.tv_butter_knife1,R.id.tv_butter_knife2,R.id.tv_butter_knife3}) List<TextView> textViews;Resource注入
@BindString(R.string.title_btn_butter_knife) String butterKnifeStr;//string注解使用 @BindDrawable(R.mipmap.ic_launcher) Drawable butterKnifeDrawable;//Drawable注解使用 @BindBitmap(R.mipmap.ic_launcher) Bitmap butterKnifeBitmap;;//Bitmap注解使用 @BindArray(R.array.day_of_week) String weeks[];//數組 @BindColor(R.color.colorPrimary) int colorPrimary;//color注解使用 @BindDimen(R.dimen.activity_horizontal_margin) Float spacer;單事件注入
/** * 帶參數 */ @OnClick(R.id.btn_butter_knife) public void onButterKnifeBtnClick() { } /** * 帶參數 */ @OnClick(R.id.btn_butter_knife) public void onButterKnifeBtnClick(View view) { Log.e(TAG, "onButterKnifeBtnClick"); } /** * 帶參數 * @param button */ @OnClick(R.id.btn_butter_knife) public void onButterKnifeBtnClick(Button button) { Log.e(TAG, "onButterKnifeBtnClick"); }也可以多個控件指定一個事件回調
/** * 兩個不同的button都相應onButterKnifeBtnClick事件回調 * * @param button */ @OnClick({R.id.btn_butter_knife, R.id.btn_butter_knife1}) public void onButterKnifeBtnClick(Button button) { Log.e(TAG, "onButterKnifeBtnClick"); switch(){ ... } }多事件回調- - ->有一些View的listener是有多個回調方法的,比如EditText添加addTextChangedListener
editText.addTextChangedListener(new TextWatcher() { @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { } @Override public void onTextChanged(CharSequence s, int start, int before, int count) { } @Override public void afterTextChanged(Editable s) { } });可以使用注解方式改成如下
@OnTextChanged(value = R.id.nameEditText, callback = OnTextChanged.Callback.BEFORE_TEXT_CHANGED) void beforeTextChanged(CharSequence s, int start, int count, int after) { } @OnTextChanged(value = R.id.nameEditText, callback = OnTextChanged.Callback.TEXT_CHANGED) void onTextChanged(CharSequence s, int start, int before, int count) { } @OnTextChanged(value = R.id.nameEditText, callback = OnTextChanged.Callback.AFTER_TEXT_CHANGED) void afterTextChanged(Editable s) { }博主將覺得能用的東西,加以修改并Mark發出,參考不知道哪位的文章,參考地址如下
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