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

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;
}

c56c
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:sodino@qq.com
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();
}
}
}