Android-- ButterKnife

標籤：

ButterKnife     是View注入架構，不會偷懶的程式員不是好程式員。

class ExampleActivity extends Activity {  TextView title;  TextView subtitle;  TextView footer;  @Override public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.simple_activity);    title = (TextView) findViewById(R.id.title);    subtitle = (TextView) findViewById(R.id.subtitle);    footer = (TextView) findViewById(R.id.footer);    // TODO Use views...  }}

而用ButterKnife之後的代碼是這樣的：

class ExampleActivity extends Activity {  @InjectView(R.id.title) TextView title;  @InjectView(R.id.subtitle) TextView subtitle;  @InjectView(R.id.footer) TextView footer;  @Override public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.simple_activity);    ButterKnife.inject(this);
　　// TODO Use "injected" views...  }}

 

 

在Activity 中注入

class ExampleActivity extends Activity {  @InjectView(R.id.title) TextView title;  @InjectView(R.id.subtitle) TextView subtitle;  @InjectView(R.id.footer) TextView footer;   @Override public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.simple_activity);    ButterKnife.inject(this);    // TODO Use "injected" views...  }}

 

在 Fragment 中注入

public class FancyFragment extends Fragment {  @InjectView(R.id.button1) Button button1;  @InjectView(R.id.button2) Button button2;   @Override View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {    View view = inflater.inflate(R.layout.fancy_fragment, container, false);    ButterKnife.inject(this, view);    // TODO Use "injected" views...    return view;  }}

在 ViewHolder 模式中注入

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 convertView;  }   static class ViewHolder {    @InjectView(R.id.title) TextView name;    @InjectView(R.id.job_title) TextView jobTitle;     public ViewHolder(View view) {      ButterKnife.inject(this, view);    }  }}

注入回呼函數

下面是幾種注入回呼函數的方法樣本:

// 帶有 Button 參數@OnClick(R.id.submit)public void sayHi(Button button) {  button.setText("Hello!");} // 不帶參數@OnClick(R.id.submit)public void submit() {  // TODO submit data to server...} // 同時注入多個 View 事件@OnClick({ R.id.door1, R.id.door2, R.id.door3 })public void pickDoor(DoorView door) {  if (door.hasPrizeBehind()) {    Toast.makeText(this, "You win!", LENGTH_SHORT).show();  } else {    Toast.makeText(this, "Try again", LENGTH_SHORT).show();  }}

Reset函數

如果需要在 介面 銷毀的時候，把注入的 View 設定為 Null， 則可以用 reset 函數：

public class FancyFragment extends Fragment {  @InjectView(R.id.button1) Button button1;  @InjectView(R.id.button2) Button button2;   @Override View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {    View view = inflater.inflate(R.layout.fancy_fragment, container, false);    ButterKnife.inject(this, view);    // TODO Use "injected" views...    return view;  }   @Override void onDestroyView() {    super.onDestroyView();    Views.reset(this);  }}

另外 還支援 可選的 View 注入，如果該 View 沒有，就沒有吧：

@Optional @InjectView(R.id.might_not_be_there) TextView mightNotBeThere; @Optional @OnClick(R.id.maybe_missing) void onMaybeMissingClicked() {  // TODO ...}

還有兩個 findViewById 函數來簡化尋找 View 的方式，如果上面都滿足不了你的需求，你可以用用他們：

View view = LayoutInflater.from(context).inflate(R.layout.thing, null);TextView firstName = Views.findById(view, R.id.first_name);TextView lastName = Views.findById(view, R.id.last_name);ImageView photo = Views.findById(view, R.id.photo);

最後，如果你是用Android Studio來作為IDE的話，那麼有一個ButterKnife的外掛程式android-butterknife-zelezny, 該外掛程式可以讓你手動產生上述注入代碼，從此讓自己成為一個更懶惰的程式員，上張吧。

 

Android-- ButterKnife