ButterKnife初级用法

ButterKnife是为Android提供的注解式框架，可以简化代码的编写，比如：

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...  }}

如果用框架写的话，则变为：

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

从这个例子也可以看出在一个activity中如何完成控件的绑定，首先bind方法是必须的，然后用@Bind可以完成各个控件的绑定，在AS中可以直接用插件生成，非常方便

下面是资源文件的绑定：

class ExampleActivity extends Activity {  @BindString(R.string.title) String title;  @BindDrawable(R.drawable.graphic) Drawable graphic;  @BindColor(R.color.red) int red; // int or ColorStateList field  @BindDimen(R.dimen.spacer) Float spacer; // int (for pixel size) or float (for exact value) field  // ...}

如果不是在一个Activity中，框架的用法有小小的区别：

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

在优化ListView时经常在adapter用到ViewHolder，对该类Butterknife也有相应的用法：

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 {    @Bind(R.id.title) TextView name;    @Bind(R.id.job_title) TextView jobTitle;    public ViewHolder(View view) {      ButterKnife.bind(this, view);    }  }}

给监听器注入：

@OnClick(R.id.submit)public void submit(View view) {  // TODO submit data to server...}

参数view有没有都无所谓，

当然，也可以为多个控件设置监听器注入：

@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();  }}

方法中也可以根据id不同来设置不同监听事件

由于Fragment与Activity有不同的生命周期，如果要绑定一个Fragment在onCreateView方法中时，需要将试图设置为空在onDestroy的时候，用unbind方法即可

public class FancyFragment extends Fragment {  @Bind(R.id.button1) Button button1;  @Bind(R.id.button2) Button button2;  @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {    View view = inflater.inflate(R.layout.fancy_fragment, container, false);    ButterKnife.bind(this, view);    // TODO Use fields...    return view;  }  @Override public void onDestroyView() {    super.onDestroyView();    ButterKnife.unbind(this);  }}