使用butterknife简化View的绑定

  butterknife是一个可以简化Android中View的绑定的开源库,它通过注解处理(annotation processing)自动生成样板文件,省去了人工编写的麻烦。使用butterknife只需在Gradle中加入:

compile 'com.jakewharton:butterknife:7.0.1'
compile 'com.jakewharton:butterknife:7.0.1'
compile 'com.jakewharton:butterknife:7.0.1'

  官方站点的已经给出了详细的使用方法。通过ButterKnife.bind() 注入后,就可以使用@Bind 和View的id来对View进行绑定,而不必再使用findViewById:
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...
}
}
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... } }
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...
  }
}

  类似地,也可以在Fragment中使用:
ublic 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);
}
}
ublic 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); } }
ublic 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);
  }
}

Fragment的生命期和Activity不同,可以在onDestroyView() 中使用ButterKnife.unbind() 解除绑定。

  在ViewHolder中使用:

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

    public ViewHolder(View view) {
        ButterKnife.bind(this, view);
    }
}

  此外还可以绑定listener:
@OnClick(R.id.submit)
public void submit(View view) {
// TODO submit data to server...
}
@OnClick(R.id.submit) public void submit(View view) { // TODO submit data to server... }
@OnClick(R.id.submit)
public void submit(View view) {
    // TODO submit data to server...
}

这里的参数是可选的,使用更具体的类型时,会自动进行类型转换:
@OnClick(R.id.submit)
public void sayHi(Button button) {
button.setText("Hello!");
}
@OnClick(R.id.submit) public void sayHi(Button button) { button.setText("Hello!"); }
@OnClick(R.id.submit)
public void sayHi(Button button) {
    button.setText("Hello!");
}

  绑定资源:
@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
@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
@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

  更多内容可以参考这里