I. Introduction:

2. Use steps:

• Install the ButterKnife plug-in for reference: Android Studio installs the ButterKnife plug-in

• Add:

  dependencies {
      classpath 'com.android.tools.build:gradle:2.2.3'
      classpath 'com.neenbedankt.gradle.plugins:android-apt:1.8' //Additional
  
      // NOTE: Do not place your application dependencies here; they belong
      // in the individual module build.gradle files
  }
  

• Add in the build.gradle file of app

  apply plugin: 'com.android.application'
  apply plugin: 'com.neenbedankt.android-apt'  //Additional
  
  ......
  
  dependencies {
      .........
      compile 'com.jakewharton:butterknife:8.1.0'    //Additional
      apt 'com.jakewharton:butterknife-compiler:8.1.0'   //Additional
  }
  

3. Unlocking Skills:

1. Eliminate findViewById()

   1. Use in Activity

      • Once we:

        mTextView1 = (TextView) findViewById(R.id.tv_1);
        

      • Now we:

        @BindView(R.id.butter_text_view_2)
        TextView mTextView2;
        

      • Note: View variables cannot be declared private ly or static ally and are called after the layout is set: ButterKnife.inject(this). Normally, it doesn't matter. We all do Generate auto-plug-in generation in the layout file location.

   2. Use in Fragment
      Also call ButterKnife.inject(this, view) after loading the layout, passing an additional parameter view. Add comments to the control. @ InjectView(R.id.fragment_text_view) can be used normally.

      View view = inflater.inflate(R.layout.fragment_simple, container, false);
      ButterKnife.inject(this, view);
      
      @BindView(R.id.fragment_text_view)
      TextView mTextView;
      mTextView.setText("TextView in Fragment are found!");
      

   3. Use in Adapter ViewHolder
      In Adapter, you can call ButterKnife.inject(this, view) within the constructor, as well as annotate above the control declaration.

      static class ViewHolder {
          @BindView(R.id.person_name)
          TextView name;
      
          public ViewHolder(View view) {
              ButterKnife.inject(this, view);
          }
      }
      

2. Omit setOnClickListener()

   • Once we:

     bt.setOnClickListener(new View.OnClickListener() {
         @Override
         public void onClick(View v) {
             finish();
         }
     });  
     

   • Now we:

     @OnClick(R.id.basic_finish_a_button)
     void finishA(View view) {
         finish();
     }
     

   • Note: Note that the method here is still not private and static, and can have either a parameter View or not.
3. Special listenable methods for some controls
   
   • ListView click on OnItemClick
   • On Checked Changed of CheckBox
   • EditText plus addTextChangedListener
     See Demo for example.

4. Binding the same event handling method for multiple views with multiple IDS at the same time
   The id of multiple view s should be wrapped in {}, "," separated.

   @OnClick({R.id.bt1, R.id.bt2, R.id.bt3, R.id.bt4})
   void editViewsClicked() {
       Toast.makeText(this, "You click the Button!", Toast.LENGTH_SHORT).show();
   } 
   

Demo examples:

1. Firstly, the effect map is shown.
                      

2. Some of the uses in MainActivity are:

   • Binding View

     @BindView(R.id.tv_1)
     TextView mTv1;
     @BindView(R.id.tv_2)
     TextView mTv2;
     @BindView(R.id.tv_3)
     TextView mTv3;
     @BindView(R.id.bt1)
     Button mBt1;
     @BindView(R.id.bt2)
     Button mBt2;
     @BindView(R.id.bt3)
     Button mBt3;
     @BindView(R.id.cb1)
     CheckBox mCb1;
     @BindView(R.id.activity_main)
     LinearLayout mActivityMain;
     
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
     
         ButterKnife.bind(this);
     }
     

   • Setting Click Events

     • Single View Binding Event

       @OnClick(R.id.bt2)
       void jumpToSecondActivity() {
           startActivity(new Intent(MainActivity.this, SecondActivity.class));
       }
       
       @OnClick(R.id.bt3)
       void jumpToOneFragment() {
           FragmentManager fragmentManager = getSupportFragmentManager();
           FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
           FirstFragment firstFragment = new FirstFragment();
           fragmentTransaction.add(R.id.fl_container, firstFragment);
           fragmentTransaction.commit();
       }
       

     • Multiple View s Bind an Event Together

       @OnClick({R.id.bt1, R.id.tv_1})
       void click() {
           Toast.makeText(MainActivity.this, "haha", Toast.LENGTH_SHORT).show();
       }
       

     • OnCheckedChanged Method for Listening to checkBox

       @OnCheckedChanged(R.id.cb1)
       void checkBoxCheckedChanged(){
           if(mCb1.isChecked())
               Toast.makeText(MainActivity.this, "Checked", Toast.LENGTH_SHORT).show();
           else
               Toast.makeText(MainActivity.this, "unChecked", Toast.LENGTH_SHORT).show();
       }
       

3. Some uses in Second Activity (Recycler View):

   • SecondActivity.java, mainly has a RecyclerView. RecyclerView does not support onItemClick, so Butterknife is gone.

     public class SecondActivity extends AppCompatActivity {
         @BindView(R.id.recyclerView)
         RecyclerView mRecyclerView;
     
         private List<String> mList = new ArrayList<>();
     
         @Override
         protected void onCreate(@Nullable Bundle savedInstanceState) {
             super.onCreate(savedInstanceState);
             setContentView(R.layout.activity_second);
             ButterKnife.bind(this);
     
             initData();
     
             mRecyclerView.setAdapter(new RecyclerAdapter(mList, this));
             mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
         }
     
         private void initData() {
             for (int i = 0; i < 30; i++)
                 mList.add(i + "");
         }
     }
     

   • The binding in Recycler Adapter is very similar to the listview binding in the Fragment below.

     public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.RecyclerViewHolder> {
     
         private List<String> data;
         private Context mContext;
     
         public RecyclerAdapter(List<String> data, Context context) {
             this.data = data;
             mContext = context;
         }
     
         @Override
         public RecyclerViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
             View view = LayoutInflater.from(mContext).inflate(R.layout.item_recycler, parent, false);
             RecyclerViewHolder holder = new RecyclerViewHolder(view);
             return holder;
         }
     
         @Override
         public void onBindViewHolder(RecyclerViewHolder holder, int position) {
             holder.mItemRecyclerTv.setText(data.get(position));
         }
     
         @Override
         public int getItemCount() {
             return data.size();
         }
     
         public class RecyclerViewHolder extends RecyclerView.ViewHolder {
     
             @BindView(R.id.item_recycler_tv)
             TextView mItemRecyclerTv;
     
             public RecyclerViewHolder(View itemView) {
                 super(itemView);
                 ButterKnife.bind(this, itemView);
             }
         }
     }
     

4. Fragment uses:

   • The ListView control is bound in FirstFragment and the click event is monitored by @OnItemClick(R.id.listview), in which the position parameter can be passed.

     public class FirstFragment extends Fragment {
     
         @BindView(R.id.listview)
         ListView mListview;
         Unbinder unbinder;
     
         private List<String> mList = new ArrayList<>();
     
         @Nullable
         @Override
         public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
             View view = inflater.inflate(R.layout.fragment_first, container, false);
             unbinder = ButterKnife.bind(this, view);
     
             initData();
     
             mListview.setAdapter(new ListAdapter(getActivity(), mList));
             return view;
         }
     
         private void initData() {
             for (int i = 0; i < 30; i++)
                 mList.add(i + "");
         }
     
         @OnItemClick(R.id.listview)
         void onListItemClick(int pos){
             Toast.makeText(getActivity(), mList.get(pos), Toast.LENGTH_SHORT).show();
         }
     
         @Override
         public void onDestroyView() {
             super.onDestroyView();
             unbinder.unbind();
         }
     }
     

   • The inflate layout in ListAdapter, butterknife can automatically generate ViewHolder for us, and the rest, as usual, copy the four methods of the Adapter.

     public class ListAdapter extends BaseAdapter {
     
         private List<String> data;
         private Context mContext;
     
         public ListAdapter(Context context, List<String> data) {
             mContext = context;
             this.data = data;
         }
     
         @Override
         public int getCount() {
             return data.size();
         }
     
         @Override
         public Object getItem(int position) {
             return data.get(position);
         }
     
         @Override
         public long getItemId(int position) {
             return position;
         }
     
         @Override
         public View getView(int position, View convertView, ViewGroup parent) {
             ViewHolder holder = null;
             if(convertView == null){
                 convertView = View.inflate(mContext, R.layout.item_list, null);
                 holder = new ViewHolder(convertView);
                 convertView.setTag(holder);
             }else {
                 holder = (ViewHolder) convertView.getTag();
             }
             holder.mItemRecyclerTv.setText(data.get(position));
             return convertView;
         }
     
         static class ViewHolder {
             @BindView(R.id.item_recycler_tv)
             TextView mItemRecyclerTv;
     
             ViewHolder(View view) {
                 ButterKnife.bind(this, view);
             }
         }
     }
     

5. Demo Download:

       Source Link