ButterKnife框架使用详解

男娘i 2022-08-20 03:17 279阅读 0赞

## 一、     什么是ButterKnife ##

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   <td> <p>ButterKnife是一个支持View注入的框架。以前总是要写很多findViewById来找到View对象，有了ButterKnife可以很轻松的省去这些步骤。</p> <p>是大神JakeWharton的力作，目前使用很广。最重要的一点，使用ButterKnife对性能基本没有损失，因为ButterKnife用到的注解并不是在运行时反射的，而是在编译的时候生成新的class。（xUtils的注入都是运行时反射，对性能影响很大。）</p> <p>ButterKnife目前的最新版本是7.0.1。</p> <p>&nbsp;</p> <p>Butter Knife 的特性</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp; 支持 Activity 中的 View 注入</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp; 支持 View 中的 View 注入</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp; 支持 View 事件回调函数注入</p> <p>&nbsp;</p> <p>目前支持如下事件回调函数：</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp; View: @OnLongClick and @OnFocusChanged.</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp; TextView: @OnEditorAction.</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp; AdapterView: @OnItemClick and @OnItemLongClick.</p> <p>&nbsp;</p> <p>&nbsp;&nbsp;&nbsp; CompoundButton: @OnCheckedChanged.</p> </td> 
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## 二、     使用ButterKnife绑定View ##

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   <td> <p>在gradle中添加依赖</p> <p>compile 'com.jakewharton:butterknife:7.0.1'</p> <p>&nbsp;</p> </td> 
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### 2.1       在Activity中注入(从7.0.0开始称绑定更合适) ###

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   <td> <pre style="">package com.qianfeng.butterknifedemo;
  
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Button;
import android.widget.TextView;
  
import butterknife.Bind;
import butterknife.ButterKnife;
  
public class MainActivity extends AppCompatActivity{
&nbsp;&nbsp;&nbsp; //给指定的TextView绑定id
&nbsp;&nbsp;&nbsp; @Bind(R.id.tv)
&nbsp;&nbsp;&nbsp; TextView tv;
&nbsp;&nbsp;&nbsp; //给指定的Button绑定id
&nbsp;&nbsp;&nbsp; @Bind(R.id.btn)
&nbsp;&nbsp;&nbsp; Button btn;
  
&nbsp;&nbsp;&nbsp; @Override
&nbsp;&nbsp;&nbsp; protected void onCreate(Bundle savedInstanceState){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; super.onCreate(savedInstanceState);
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; setContentView(R.layout.activity_main);
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;ButterKnife.bind(this);
  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tv.setText("哈哈");
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; btn.setText("呵呵呵");
&nbsp;&nbsp;&nbsp; }
}</pre> <p>&nbsp;</p> <p>注意：需要绑定的控件不能是private和static的</p> </td> 
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### 2.2       在Fragment中绑定 ###

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   <td> <pre style="">package com.qianfeng.butterknifedemo;
  
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;
  
import butterknife.Bind;
import butterknife.ButterKnife;
  
  /**
&nbsp;* A simple {@link Fragment} subclass.
&nbsp;*/
  public class BlankFragment extends Fragment{
&nbsp;&nbsp;&nbsp; @Bind(R.id.f_tv)
&nbsp;&nbsp;&nbsp; TextView f_tv;
  
&nbsp;&nbsp;&nbsp; @Bind(R.id.f_btn)
&nbsp;&nbsp;&nbsp; Button f_btn;
  
&nbsp;&nbsp;&nbsp; public BlankFragment(){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // Required empty public constructor
&nbsp;&nbsp;&nbsp; }
  
&nbsp;&nbsp;&nbsp; @Override
&nbsp;&nbsp;&nbsp; public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; savedInstanceState){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // Inflate the layout for this fragment
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return inflater.inflate(R.layout.fragment_blank, container, false);
&nbsp;&nbsp;&nbsp; }
  
&nbsp;&nbsp;&nbsp; @Override
&nbsp;&nbsp;&nbsp; public void onViewCreated(View view, @Nullable Bundle savedInstanceState){
      </pre> <pre style="">//绑定
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ButterKnife.bind(this, view);
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; f_tv.setText("最新的数据");
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; f_btn.setText("最新的数据");
&nbsp;&nbsp;&nbsp; }
}</pre> <p>&nbsp;</p> </td> 
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### 2.3       在ViewHolder中绑定 ###

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   <td> <pre style="">&nbsp;&nbsp; &nbsp;static class ViewHolder {
      </pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; @InjectView(R.id.person_name)</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; TextView name;</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; @InjectView(R.id.person_age)</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; TextView age;</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; @InjectView(R.id.person_location)</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; TextView location;</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; @InjectView(R.id.person_work)</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; TextView work;</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;public ViewHolder(View view) {
      </pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; //绑定</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ButterKnife.inject(this, view);</pre> <pre style="">&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }</pre> <pre style="">&nbsp;&nbsp;&nbsp; }</pre> <p>注意：我们在ViewHolder中添加了一个有View参数的构造方法，以后再也不需要在getView方法中findViewById了</p> </td> 
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## 三、     使用ButterKnife绑定事件回调方法 ##

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   <td> <pre style="">@OnClick({R.id.btn})
  public void ok(){ //方法形参列表中可以有View也可以没有
&nbsp;&nbsp;&nbsp; Toast.makeText(this, "点击了Activity中的按钮", Toast.LENGTH_SHORT).show();
  }</pre> <p>&nbsp;</p> <p>&nbsp;</p> <p>也可以多个View控件的点击事件绑定在一个方法中。</p> <p>&nbsp;</p> <p>除了点击事件@OnClick,还有ListView的点击@OnItemClick, CheckBox的@OnCheckedChanged等等.</p> <p>&nbsp;</p> </td> 
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## 四、     把多个View放在一起组成View List ##

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   <td> <pre style="">@Bind({R.id.btn,R.id.tv})&nbsp; //把多个View放入List集合中
List&lt;View&gt; views;</pre> <p>&nbsp;</p> </td> 
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## 五、     ButterKnife的Apply方法 ##

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   <td> <p>apply方法可以对指定的list集合中的View进行批量操作</p> <p>共有三个重载方法：</p> <p></p> <p>&nbsp;</p> <p>其中Action和Setter是ButterKnife的内部接口。</p> <p>&nbsp;</p> <p>例如：对views集合中所有 的view都会分别指向applay中的方法。</p> <pre style="">ButterKnife.apply(views, new ButterKnife.Action&lt;View&gt;(){
&nbsp;&nbsp;&nbsp; @Override
&nbsp;&nbsp;&nbsp; public void apply(View view, int index){
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; TextView tv1 = (TextView) view;
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; tv1.setText("aabbbaa");
&nbsp;&nbsp;&nbsp; }
});</pre> <p>&nbsp;</p> <pre style="">ButterKnife.apply(views, new ButterKnife.Setter&lt;View, String&gt;(){
  
&nbsp;&nbsp;&nbsp; @Override
&nbsp;&nbsp;&nbsp; public void set(View view, String value, int index){
  
&nbsp;&nbsp;&nbsp; }
}, "aaaaa");</pre> <p>&nbsp;</p> </td> 
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## 六、     ButterKnife一些其他常用方法 ##

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   <td> <p>1、&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 解除绑定</p> <pre style="">@Override
  protected void onDestroy(){
&nbsp;&nbsp;&nbsp; super.onDestroy();
&nbsp;&nbsp;&nbsp; //解绑。&nbsp; 即把上面绑定的view全部置为null
&nbsp;&nbsp;&nbsp; ButterKnife.unbind(this);
  
  }</pre> <p>&nbsp;</p> <p>2、&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 选择性绑定。</p> <p>默认情况下绑定View和事件的时候，控件的id是必须存在的，否则会抛出异常。&nbsp; 选择性绑定可以做到如果id存在就绑定，否则不绑定，不抛出任何异常。&nbsp; 想达到这样的想过只需要在@bind 或@onClick前添加@null即可</p> <pre style="">@Nullable @Bind(R.id.f_tv)
TextView tv;</pre> <p>&nbsp;</p> <p><a rel="nofollow"></a><a rel="nofollow">3、&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 多方法绑定</a></p> <p>@OnItemSelected(R.id.list_view)</p> <p>void onItemSelected(int position) { </p> <p>&nbsp; // TODO ...</p> <p>}</p> <p>&nbsp;</p> <p>@OnItemSelected(value = R.id.maybe_missing, callback = NOTHING_SELECTED)</p> <p>void onNothingSelected() { </p> <p>&nbsp; // TODO ...</p> <p>}</p> <p>4、&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; findById方法。以前我们调用findViewById需要进行强制类型转换。使用它可以免除强制类型转换，可以自动完成类型转换。</p> <p>View view = LayoutInflater.from(context).inflate(R.layout.thing, null);</p> <p>TextView firstName = ButterKnife.findById(view, R.id.first_name);</p> <p>TextView lastName = ButterKnife.findById(view, R.id.last_name);</p> <p>ImageView photo = ButterKnife.findById(view, R.id.photo);</p> <p>&nbsp;</p> </td> 
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## 六、     在Android studio中使用插件自动生成ButterKnife需要的代码    ##

## 使用插件：AndroidButterKnife Zelezny      ##

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