1 前言

前面的文章注解框架源碼分析（XUtils百侧、ButterKnife）和ButterKnife編譯時生成代碼原理：butterknife-compiler源碼分析老赤，按照源碼的思路我們自己打造一款IOC注解框架唤崭，因為ButterKnife的源碼實現(xiàn)難度過大士聪，我先仿照xUtils的源碼方式某饰，反射注解實現(xiàn)。
雖說反射注解對性能有影響剃袍，但是影響是極小黄刚，相比I渲染和Bitmap以及Service和Handler上的內(nèi)存泄露不是一個量級的，編程一開始不糾結完美化民效，實現(xiàn)這個IOC框架是為了提升自己的編碼能力憔维，也是提高自己對項目整體代碼提高可控性涛救。

2 控件屬性注入

Annotation注解需要了解Java中Annotation用法、Java Annotation 總結
屬性注入代碼：

/*
 * ElementType.FIELD 代表annotation的位置
 * FIELD：屬性注解
 * CONSTRUCTOR：構造器注解
 * METHOD：方法注解
 * TYPE：類上注解
 */
@Target(ElementType.FIELD)
/*
@Retention(RetentionPolicy.CLASS)什么時候生效
CLASS 編譯時
RUNTIME 運行時
SOURCR 源碼資源
 */
@Retention(RetentionPolicy.RUNTIME)
public @interface FindView {

    //@FindView(R.id.xxxx)
    @IdRes int value();
}

public class SteadyoungIOC {
    //activity使用
    public static void inject(Activity activity){
        inject(new ViewFinder(activity),activity);
    }

    //View使用
    public static void inject(View view){
        inject(new ViewFinder(view),view);
    }

    //Fragment使用
    public static void inject(View view,Object object){
        inject(new ViewFinder(view),object);
    }

    //兼容上述三種方式
    private static void inject(ViewFinder finder,Object object){
        injectField(finder,object);
        injectEvent(finder,object);
    }

    /**
     * 注入屬性
      * @param finder
     * @param object
     */
    private static void injectField(ViewFinder finder, Object object) {
        //1.獲取類里面的所有屬性
        Class<?> clazz = object.getClass();
        //獲取所有屬性包括私有和公有
        Field[] fields = clazz.getDeclaredFields();
        //2.獲取ViewById的里面的value值
        for(Field field : fields){
            FindView viewById = field.getAnnotation(FindView.class);
            if(viewById != null){
                int viewId = viewById.value();
                //3.findViewById找到View
                View view = finder.findViewById(viewId);
                if (view != null) {
                    // 4. 反射注入View屬性
                    // 設置所有屬性都能注入包括私有和公有
                    field.setAccessible(true);
                    try {
                        field.set(object, view);
                    } catch (IllegalAccessException e) {
                        e.printStackTrace();
                    }
                } else {
                    throw new RuntimeException("Invalid @ViewInject for "
                            + clazz.getSimpleName() + "." + field.getName());
                }
            }
        }

    }

    /**
     * 注入事件
     * @param finder
     * @param object
     */
    private static void injectEvent(ViewFinder finder, Object object) {
      //TODO
    }

public class ViewFinder {
    private Activity mActivity;
    private View mView;

    public ViewFinder(Activity activity) {
        this.mActivity = activity;
    }

    public ViewFinder(View view) {
        this.mView = view;
    }

    /**
     * 判斷容器然后 根據(jù)容器和控件ID獲取控件View
     * @param viewId
     * @return
     */
    public View findViewById(@IdRes int viewId){
        return mActivity!= null ? mActivity.findViewById(viewId) : mView.findViewById(viewId);
    }
}

3 點擊事件注入

我先實現(xiàn)setOnclickListener點擊事件业扒，其他事件后期實現(xiàn)检吆。

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface OnClick {
    @IdRes int[] value();
}

    /**
     * 注入事件
     * @param finder
     * @param object
     */
    private static void injectEvent(ViewFinder finder, Object object) {
        //TODO
        //1.獲取類里面的所有方法
        Class<?> clazz = object.getClass();
        Method[] methods = clazz.getDeclaredMethods();
        //2.獲取OnClick的里面的Value值
        for ( Method method: methods ) {
            OnClick onClick = method.getAnnotation(OnClick.class);
            if(onClick != null){
                int[] viewIds = onClick.value();
                for( int viewId : viewIds){
                    //3.findViewById找到View
                    View view = finder.findViewById(viewId);
                    //4.view.setOnClickListener
                    view.setOnClickListener(new DeclaredOnClickListener(method,object));
                }
            }
        }
    }

    private static class DeclaredOnClickListener implements View.OnClickListener {
        private Method mMethod;
        private Object mObject;

        public DeclaredOnClickListener(Method mMethod, Object mObject) {
            this.mMethod = mMethod;
            this.mObject = mObject;
        }

        @Override
        public void onClick(View v) {
            try {
                //打開權限
                mMethod.setAccessible(true);
                mMethod.invoke(mObject,v);
            } catch (Exception e) {
                e.printStackTrace();
                try {
                    mMethod.invoke(mObject,null);
                } catch (Exception e1) {
                    e1.printStackTrace();
                }
            }
        }
    }

4 擴展動態(tài)檢測網(wǎng)絡注解

最后擴展動態(tài)檢測網(wǎng)絡注解，可以在點擊某些按鈕或者圖片是需要訪問網(wǎng)絡前檢測網(wǎng)絡狀態(tài)程储，避免打不開網(wǎng)頁或者獲取不到數(shù)據(jù)等網(wǎng)絡問題的情況蹭沛！

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface CheckNet {
    String value();
}

    /**
     * 注入事件
     * @param finder
     * @param object
     */
    private static void injectEvent(ViewFinder finder, Object object) {
        //TODO
        //1.獲取類里面的所有方法
        Class<?> clazz = object.getClass();
        Method[] methods = clazz.getDeclaredMethods();
        //2.獲取OnClick的里面的Value值
        for ( Method method: methods ) {
            OnClick onClick = method.getAnnotation(OnClick.class);
            if(onClick != null){
                int[] viewIds = onClick.value();
                for( int viewId : viewIds){
                    //3.findViewById找到View
                    View view = finder.findViewById(viewId);
                    //判斷是否有檢測網(wǎng)絡需求
                    boolean isCheckNet = method.getAnnotation(CheckNet.class) != null;
                    String message = null;
                    if(isCheckNet){
                        //獲取無網(wǎng)絡提示信息
                        message = method.getAnnotation(CheckNet.class).value();
                    }
                    //4.view.setOnClickListener
                    view.setOnClickListener(new DeclaredOnClickListener(method,object,isCheckNet,message));
                }
            }
        }
    }

    private static class DeclaredOnClickListener implements View.OnClickListener {
        private Method mMethod;
        private Object mObject;
        private boolean isCheckNet;
        private String message;

        public DeclaredOnClickListener(Method mMethod, Object mObject, boolean isCheckNet, String message) {
            this.mMethod = mMethod;
            this.mObject = mObject;
            this.isCheckNet = isCheckNet;
            this.message = message;
        }

        @Override
        public void onClick(View v) {
            if(isCheckNet){
                Log.d("isCheckNet", "onClick:111111111111111111 ");
                if(!isNetworkConnected(v.getContext())){
                    Toast.makeText(v.getContext(), TextUtils.isEmpty(message) ? "網(wǎng)絡不給力，請檢查網(wǎng)絡連接章鲤！" : message ,Toast.LENGTH_SHORT).show();
                    return;
                }
            }
            try {
                //打開權限
                mMethod.setAccessible(true);
                mMethod.invoke(mObject,v);
            } catch (Exception e) {
                e.printStackTrace();
                try {
                    mMethod.invoke(mObject,null);
                } catch (Exception e1) {
                    e1.printStackTrace();
                }
            }
        }
    }

    /**
     *獲取網(wǎng)絡連接狀態(tài)
     * @param context
     * @return true網(wǎng)絡連接正常 false無網(wǎng)絡
     */
    private static boolean isNetworkConnected(Context context){
        if(context != null){
            ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
            NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
            if(networkInfo != null){
                return networkInfo.isAvailable();
            }
        }
        return false;
    }

下面放上測試代碼和測試結果：

public class MainActivity extends AppCompatActivity {

    /****Hello World!****/
    @FindView(R.id.test_tv)
    private TextView mTestTv;
    @FindView(R.id.test_iv)
    private ImageView mTestIv;
    /****TestButton****/
    @FindView(R.id.test_btn)
    private Button mTestBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        SteadyoungIOC.inject(this);
        mTestTv.setText("測試文本");
        mTestIv.setBackgroundColor(Color.RED);
        mTestBtn.setText("測試按鈕");
    }

    @OnClick(R.id.test_tv)
    private void testTvClick(TextView testTv) {
        Toast.makeText(this,"點擊了文字",Toast.LENGTH_SHORT).show();
    }

    @OnClick(R.id.test_iv)
    private void testIvClick(ImageView testIv) {
        mTestIv.setBackgroundColor(Color.BLUE);
        Toast.makeText(this,"點擊了圖片",Toast.LENGTH_SHORT).show();
    }

    @CheckNet("親摊灭！網(wǎng)絡不給力哦！")
    @OnClick(R.id.test_btn)
    private void testBtnClick(Button testBtn) {
        Toast.makeText(this,"點擊了按鈕",Toast.LENGTH_SHORT).show();
    }
}

steadyoungioctest.gif

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