Android Hook View技术实践

深碍√TFBOYSˉ_ 2022-06-16 11:12 219阅读 0赞

## **Android Hook View技术实践** ##

#### **Hook View实现原理** ####

Hook View技术是通过获取View类中的View.OnClickListener对象mClickListener（在API14以上，mClickListener对象封装在ListenerInfo类中），通过反射方式获取该对象，再通过代理的方式处理，创建一个代理类，在代理类中设置mClickListener对象，同时做一些你需要事件处理（如埋点事件）。

具体实现看下面代码

#### **Hook View实践案例** ####

MainActivity

public class MainActivity extends AppCompatActivity { 
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            final Button button = (Button) findViewById(R.id.btn1);
    
            button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.e("MainActivity", "onClick--> button: " + v.getId());
                }
            });
    
            final ConstraintLayout constraintLayout = (ConstraintLayout) findViewById(R.id.root);
    
            constraintLayout.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.e("MainActivity", "onClick--> constraintLayout: " + v.getId());
                }
            });
    
            getWindow().getDecorView().post(new Runnable() {
                @Override
                public void run() {
                    HookViewManager.getInstance().hookView(button);
                    HookViewManager.getInstance().hookView(constraintLayout);
                }
            });
        }
    }

activity\_main.xml

<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/root"
        tools:context="com.yundoku.hookview.MainActivity">
    
        <Button
            android:id="@+id/btn1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Hello World!"
            app:layout_constraintBottom_toBottomOf="parent"
            app:layout_constraintLeft_toLeftOf="parent"
            app:layout_constraintRight_toRightOf="parent"
            app:layout_constraintTop_toTopOf="parent" />
    
    </android.support.constraint.ConstraintLayout>

HookViewManager

public class HookViewManager { 
    
        private static class Holder { 
            private final static HookViewManager INSTANCE = new HookViewManager();
        }
    
        private HookViewManager() {
    
        }
    
        private class OnClickListenerProxy implements View.OnClickListener { 
    
            private View.OnClickListener listener;
    
            public OnClickListenerProxy(View.OnClickListener listener) {
                this.listener = listener;
            }
    
            @Override
            public void onClick(View v) {
                if (listener != null) {
                    hook(v);
                    listener.onClick(v);
                }
            }
    
            private void hook(View view) {
                Log.e("HookViewManager", "hook--> id: " + view.getId());
            }
        }
    
        public static HookViewManager getInstance() {
            return Holder.INSTANCE;
        }
    
        public void hookView(View view) {
            View.OnClickListener oldOnClickListener = getClickListener(view);
            if (oldOnClickListener == null) {
                return;
            }
            OnClickListenerProxy newOnClickListener = new OnClickListenerProxy(oldOnClickListener);
            view.setOnClickListener(newOnClickListener);
        }
    
        private View.OnClickListener getClickListener(View view) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
                return getClickListenerV14(view);
            } else {
                return getClickListenerV(view);
            }
        }
    
        /** * API 14 以下 */
        private View.OnClickListener getClickListenerV(View view) {
            View.OnClickListener listener = null;
            try {
                Class<?> clazz = Class.forName("android.view.View");
                Field field = clazz.getDeclaredField("mOnClickListener");
                listener = (View.OnClickListener) field.get(view);
            } catch (ClassNotFoundException e) {
                Log.e("HookViewManager", "ClassNotFoundException: " + e.getMessage());
            } catch (NoSuchFieldException e) {
                Log.e("HookViewManager", "NoSuchFieldException: " + e.getMessage());
            } catch (IllegalAccessException e) {
                Log.e("HookViewManager", "IllegalAccessException: " + e.getMessage());
            }
            return listener;
        }
    
        /** * API 14 以上 */
        private View.OnClickListener getClickListenerV14(View view) {
            View.OnClickListener listener = null;
            try {
                Class<?> clazz = Class.forName("android.view.View");
                Field field = clazz.getDeclaredField("mListenerInfo");
                Object listenerInfo = null;
                if (field != null) {
                    field.setAccessible(true);
                    listenerInfo = field.get(view);
                }
                Class<?> cls = Class.forName("android.view.View$ListenerInfo");
                Field declaredField = cls.getDeclaredField("mOnClickListener");
                if (declaredField != null && listenerInfo != null) {
                    listener = (View.OnClickListener) declaredField.get(listenerInfo);
                }
            } catch (ClassNotFoundException e) {
                Log.e("HookViewManager", "ClassNotFoundException: " + e.getMessage());
            } catch (NoSuchFieldException e) {
                Log.e("HookViewManager", "NoSuchFieldException: " + e.getMessage());
            } catch (IllegalAccessException e) {
                Log.e("HookViewManager", "IllegalAccessException: " + e.getMessage());
            }
            return listener;
        }
    }