InputMethodManager导致的内存泄漏

最近在使用LeakCanary的时候在首屏的SplashActivity经常会遇到内存泄漏的情况 看了下报错信息指向了 InputMethodManager的方法。网上的解决方法很多，测试了几种，在这里记录一下以防又忘了。

Solution:在onDestroy（）中添加以下方法

具体参考此链接 http://blog.csdn.net/sodino/article/details/32188809

1.第一种解决方法(实测好像没什么用)

:

InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE);
        try {
            InputMethodManager.class.getDeclaredMethod("windowDismissed", IBinder.class).invoke(imm,
                    getWindow().getDecorView().getWindowToken());
        } catch (Exception e){
            e.printStackTrace();
        }

2.第二种解决方法

/**
     * Fix for https://code.google.com/p/android/issues/detail?id=171190 .
     *
     * When a view that has focus gets detached, we wait for the main thread to be idle and then
     * check if the InputMethodManager is leaking a view. If yes, we tell it that the decor view got
     * focus, which is what happens if you press home and come back from recent apps. This replaces
     * the reference to the detached view with a reference to the decor view.
     *
     * Should be called from {@link Activity#onCreate(android.os.Bundle)} )}.
     */
    public static void fixFocusedViewLeak(Application application) {

        // Don't know about other versions yet.
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1|| Build.VERSION.SDK_INT > 23) {
            return;
        }

        final InputMethodManager inputMethodManager =
                (InputMethodManager) application.getSystemService(Context.INPUT_METHOD_SERVICE);

        final Field mServedViewField;
        final Field mHField;
        final Method finishInputLockedMethod;
        final Method focusInMethod;
        try {
            mServedViewField = InputMethodManager.class.getDeclaredField("mServedView");
            mServedViewField.setAccessible(true);
            mHField = InputMethodManager.class.getDeclaredField("mServedView");
            mHField.setAccessible(true);
            finishInputLockedMethod = InputMethodManager.class.getDeclaredMethod("finishInputLocked");
            finishInputLockedMethod.setAccessible(true);
            focusInMethod = InputMethodManager.class.getDeclaredMethod("focusIn", View.class);
            focusInMethod.setAccessible(true);
        } catch (NoSuchMethodException | NoSuchFieldException unexpected) {
            Log.e("IMMLeaks", "Unexpected reflection exception", unexpected);
            return;
        }

        application.registerActivityLifecycleCallbacks(new Application.ActivityLifecycleCallbacks() {
            @Override
            public void onActivityDestroyed(Activity activity){

            }

            @Override
            public void onActivityStarted(Activity activity){

            }

            @Override
            public void onActivityResumed(Activity activity){

            }

            @Override
            public void onActivityPaused(Activity activity){

            }

            @Override
            public void onActivityStopped(Activity activity){

            }

            @Override
            public void onActivitySaveInstanceState(Activity activity, Bundle bundle){

            }

            @Override public void onActivityCreated(Activity activity, Bundle savedInstanceState) {
                ReferenceCleaner cleaner = new ReferenceCleaner(inputMethodManager, mHField, mServedViewField,
                                finishInputLockedMethod);
                View rootView = activity.getWindow().getDecorView().getRootView();
                ViewTreeObserver viewTreeObserver = rootView.getViewTreeObserver();
                viewTreeObserver.addOnGlobalFocusChangeListener(cleaner);
            }
        });
    }

    static class ReferenceCleaner
            implements MessageQueue.IdleHandler, View.OnAttachStateChangeListener,
            ViewTreeObserver.OnGlobalFocusChangeListener {

        private final InputMethodManager inputMethodManager;
        private final Field mHField;
        private final Field mServedViewField;
        private final Method finishInputLockedMethod;

        ReferenceCleaner(InputMethodManager inputMethodManager, Field mHField, Field mServedViewField,
                         Method finishInputLockedMethod) {
            this.inputMethodManager = inputMethodManager;
            this.mHField = mHField;
            this.mServedViewField = mServedViewField;
            this.finishInputLockedMethod = finishInputLockedMethod;
        }

        @Override public void onGlobalFocusChanged(View oldFocus, View newFocus) {
            if (newFocus == null) {
                return;
            }
            if (oldFocus != null) {
                oldFocus.removeOnAttachStateChangeListener(this);
            }
            Looper.myQueue().removeIdleHandler(this);
            newFocus.addOnAttachStateChangeListener(this);
        }

        @Override public void onViewAttachedToWindow(View v) {
        }

        @Override public void onViewDetachedFromWindow(View v) {
            v.removeOnAttachStateChangeListener(this);
            Looper.myQueue().removeIdleHandler(this);
            Looper.myQueue().addIdleHandler(this);
        }

        @Override public boolean queueIdle() {
            clearInputMethodManagerLeak();
            return false;
        }

        private void clearInputMethodManagerLeak() {
            try {
                Object lock = mHField.get(inputMethodManager);
                // This is highly dependent on the InputMethodManager implementation.
                synchronized (lock) {
                    View servedView = (View) mServedViewField.get(inputMethodManager);
                    if (servedView != null) {

                        boolean servedViewAttached = servedView.getWindowVisibility() != View.GONE;

                        if (servedViewAttached) {
                            // The view held by the IMM was replaced without a global focus change. Let's make
                            // sure we get notified when that view detaches.

                            // Avoid double registration.
                            servedView.removeOnAttachStateChangeListener(this);
                            servedView.addOnAttachStateChangeListener(this);
                        } else {
                            // servedView is not attached. InputMethodManager is being stupid!
                            Activity activity = extractActivity(servedView.getContext());
                            if (activity == null || activity.getWindow() == null) {
                                // Unlikely case. Let's finish the input anyways.
                                finishInputLockedMethod.invoke(inputMethodManager);
                            } else {
                                View decorView = activity.getWindow().peekDecorView();
                                boolean windowAttached = decorView.getWindowVisibility() != View.GONE;
                                if (!windowAttached) {
                                    finishInputLockedMethod.invoke(inputMethodManager);
                                } else {
                                    decorView.requestFocusFromTouch();
                                }
                            }
                        }
                    }
                }
            } catch (IllegalAccessException |InvocationTargetException unexpected) {
                Log.e("IMMLeaks", "Unexpected reflection exception", unexpected);
            }
        }

        private Activity extractActivity(Context context) {
            while (true) {
                if (context instanceof Application) {
                    return null;
                } else if (context instanceof Activity) {
                    return (Activity) context;
                } else if (context instanceof ContextWrapper) {
                    Context baseContext = ((ContextWrapper) context).getBaseContext();
                    // Prevent Stack Overflow.
                    if (baseContext == context) {
                        return null;
                    }
                    context = baseContext;
                } else {
                    return null;
                }
            }
        }
    }

3.第三种方法

public static void fixInputMethodManagerLeak(Context destContext) {  
    if (destContext == null) {  
        return;  
    }  

    InputMethodManager imm = (InputMethodManager) destContext.getSystemService(Context.INPUT_METHOD_SERVICE);  
    if (imm == null) {  
        return;  
    }  

    String [] arr = new String[]{"mCurRootView", "mServedView", "mNextServedView"};  
    Field f = null;  
    Object obj_get = null;  
    for (int i = 0;i < arr.length;i ++) {  
        String param = arr[i];  
        try{  
            f = imm.getClass().getDeclaredField(param);  
            if (f.isAccessible() == false) {  
                f.setAccessible(true);  
            } // author: sodino mail:[email protected]  
            obj_get = f.get(imm);  
            if (obj_get != null && obj_get instanceof View) {  
                View v_get = (View) obj_get;  
                if (v_get.getContext() == destContext) { // 被InputMethodManager持有引用的context是想要目标销毁的  
                    f.set(imm, null); // 置空，破坏掉path to gc节点  
                } else {  
                    // 不是想要目标销毁的，即为又进了另一层界面了，不要处理，避免影响原逻辑,也就不用继续for循环了  
                    if (QLog.isColorLevel()) {  
                        QLog.d(ReflecterHelper.class.getSimpleName(), QLog.CLR, "fixInputMethodManagerLeak break, context is not suitable, get_context=" + v_get.getContext()+" dest_context=" + destContext);  
                    }  
                    break;  
                }  
            }  
        }catch(Throwable t){  
            t.printStackTrace();  
        }  
    }  
}