一、Android Studio配置Butterknife

实验环境：Android Studio 3.5.2 版本、SDK API 29、Butterknife 1.6.0

1.打开Android Studio的Settings进行配置

2.找到Settings中的Plugins，在搜索框中输入Butterknife

插件：Android ButterKnife Zelezny
点击 install 然后 Restart IDE

3.进行build.gradle(Module:app)配置

android {  
  ...
  compileOptions {  
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  } 

dependencies {
    implementation 'com.jakewharton:butterknife:10.1.0'
    annotationProcessor 'com.jakewharton:butterknife-compiler:10.1.0'
}

二、Butterknife的使用

1.XML创建组件

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
    <Button
        android:text="测试案例_1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/Btn_lab_1">
    </Button>
    <Button
        android:text="测试案例_2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/Btn_lab_2">
    </Button>
</LinearLayout>

2.在Android Studio 选中MainActivity中布局文件名称点击右键，然后点击Generate

3.选择是否生成触发事件及修改变量名称

4.完整代码

• Activity

public class MainActivity extends AppCompatActivity {
    @BindView(R.id.Btn_lab_1)
    Button BtnLab1;
    @BindView(R.id.Btn_lab_2)
    Button BtnLab2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
    }


    @OnClick({R.id.Btn_lab_1, R.id.Btn_lab_2})
    public void onViewClicked(View view) {
        switch (view.getId()) {
            case R.id.Btn_lab_1:
                Toast.makeText(getApplicationContext(),"Btn_lab_1",Toast.LENGTH_LONG).show();
                break;
            case R.id.Btn_lab_2:
                Toast.makeText(getApplicationContext(),"Btn_lab_2",Toast.LENGTH_LONG).show();
                break;
        }
    }
}

• Fragment

public class ThisFragment extends Fragment {
    private Context context;
    private static ThisFragment thisFragment;

    private ThisFragment(Context context) {
        this.context = context;
    }

    public static ThisFragment getThisFragment(Context context) {
        if (thisFragment == null) {
            thisFragment = new ThisFragment(context);
        }
        return thisFragment;
    }

    @BindView(R.id.Frag_Btn_1)
    Button FragBtn1;
    @BindView(R.id.Frag_Btn_2)
    Button FragBtn2;


    Unbinder unbinder;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_view, container, false);
        unbinder = ButterKnife.bind(this, view);  //绑定
        return super.onCreateView(inflater, container, savedInstanceState);
    }

    @OnClick({R.id.Frag_Btn_1, R.id.Frag_Btn_2})
    public void onViewClicked(View view) {
        switch (view.getId()) {
            case R.id.Frag_Btn_1:
                Toast.makeText(context, "Btn_frag_lab_1", Toast.LENGTH_LONG).show();
                break;
            case R.id.Frag_Btn_2:
                Toast.makeText(context, "Btn_frag_lab_2", Toast.LENGTH_LONG).show();
                break;
        }
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        unbinder.unbind(); // 解除绑定
    }
}

5.其他标签

@BindArray 绑定string里面array数组；@BindArray(R.array.city ) String[] citys ;

@BindBitmap 绑定图片资源为Bitmap；@BindBitmap( R.mipmap.wifi ) Bitmap bitmap;

@BindString 绑定一个String id为一个String变量；@BindString( R.string.app_name ) String meg;

@BindColor 绑定color；@BindColor(R.color.colorAccent) int black;

@BindDimen 绑定Dimen；@BindDimen(R.dimen.borth_width) int mBorderWidth;

@BindDrawable 绑定Drawable；@BindDrawable(R.drawable.test_pic) Drawable mTestPic;

@BindFloat 绑定float

@BindInt 绑定int

@BindBool 绑定boolean值

三、常见错误及其解决方法

错误信息：

Andorid使用Butterknife报错java.lang.NoSuchMethodError: No static method metafactory

 java.lang.NoSuchMethodError: No static method metafactory(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodType;Ljava/lang/invoke/MethodHandle;Ljava/lang/invoke/MethodType;)Ljava/lang/invoke/CallSite; in class Ljava/lang/invoke/LambdaMetafactory; or its super classes (declaration of 'java.lang.invoke.LambdaMetafactory' appears in /apex/com.android.runtime/javalib/core-oj.jar)
        at butterknife.internal.DebouncingOnClickListener.<clinit>(DebouncingOnClickListener.java:12)
        at com.example.androiddemo.MainActivity_ViewBinding.<init>(MainActivity_ViewBinding.java:32)

解决方法：

将Java版本设置为1.8或更高版本。我们现在在源代码中使用Java 8功能（是lambdas），这可以让Android的编译器来处理它

android {  
  ...
  compileOptions {  
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  } 

然后重新Sync,编译运行