Framework 全局监听屏幕点击事件 INPUT_EVENT_INJECTION

2023-04-23 226

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简介： Framework 全局监听屏幕点击事件 INPUT_EVENT_INJECTION

需求：用户点击屏幕后取消原有定时任务，无操作后顺延原来定时任务

简单分析

要想全局监听，那必须是在 framework 中了，应该从哪里切入呢？先看看 log，每点击一次屏幕后发现打印

InputDispatcher: Asynchronous input event injection succeeded.

全局搜索找到 frameworks\native\services\inputflinger\InputDispatcher.cpp 中

这就有点难顶了，cpp 中想要通知 java 层还是有点困难的，一开始尝试了在此处发送广播

#include <unistd.h>
switch (injectionResult) {
case INPUT_EVENT_INJECTION_SUCCEEDED:
ALOGV(“Asynchronous input event injection succeeded.”);
execlp(“am”, “am”, “broadcast”,
“-n”, “com.android.systemui/com.pdd.sutie.CustomerReceiver”,
“-a”, “com.pdd.action.inputevent.inject”,
NULL);
exit(errno);

通过函数 execlp() 调用 am 指令发送广播，尝试后发现会把 system 进程搞挂，看来 execlp() 不能在此使用，那就只能搂底浆了，

从 cpp 往上找，最终找到

frameworks\base\services\core\java\com\android\server\input\InputManagerService.java 中

调用顺序如下

InputManagerService.java
injectInputEventInternal(event, mode)
com_android_server_input_InputManagerService.cpp
im->getInputManager()->getDispatcher()->injectInputEvent(
InputDispatcher.cpp
int32_t InputDispatcher::injectInputEvent(const InputEvent* event,
int32_t injectorPid, int32_t injectorUid, int32_t syncMode, int32_t timeoutMillis,
uint32_t policyFlags)

解决办法

frameworks\base\services\core\java\com\android\server\input\InputManagerService.java

@Override // Binder call
    public boolean injectInputEvent(InputEvent event, int mode) {
        return injectInputEventInternal(event, mode);
    }
    private boolean injectInputEventInternal(InputEvent event, int mode) {
        if (event == null) {
            throw new IllegalArgumentException("event must not be null");
        }
        if (mode != InputManager.INJECT_INPUT_EVENT_MODE_ASYNC
                && mode != InputManager.INJECT_INPUT_EVENT_MODE_WAIT_FOR_FINISH
                && mode != InputManager.INJECT_INPUT_EVENT_MODE_WAIT_FOR_RESULT) {
            throw new IllegalArgumentException("mode is invalid");
        }
        final int pid = Binder.getCallingPid();
        final int uid = Binder.getCallingUid();
        final long ident = Binder.clearCallingIdentity();
        final int result;
        try {
            result = nativeInjectInputEvent(mPtr, event, pid, uid, mode,
                    INJECTION_TIMEOUT_MILLIS, WindowManagerPolicy.FLAG_DISABLE_KEY_REPEAT);
        } finally {
            Binder.restoreCallingIdentity(ident);
        }
        switch (result) {
            case INPUT_EVENT_INJECTION_PERMISSION_DENIED:
                Slog.w(TAG, "Input event injection from pid " + pid + " permission denied.");
                throw new SecurityException(
                        "Injecting to another application requires INJECT_EVENTS permission");
            case INPUT_EVENT_INJECTION_SUCCEEDED:
                //cczheng add for listen lcd input start
                android.util.Log.e("InputDispatcher", "Input event injection from pid " + pid + " succeeded.");
                Intent pIntent = new Intent("com.pdd.action.inputevent.inject");
                pIntent.setComponent(new android.content.ComponentName("com.android.systemui",
                            "com.pdd.sutie.CustomerReceiver"));
                mContext.sendBroadcast(pIntent);
                //cczheng add for listen lcd input end
                return true;
            case INPUT_EVENT_INJECTION_TIMED_OUT:
                Slog.w(TAG, "Input event injection from pid " + pid + " timed out.");
                return false;
            case INPUT_EVENT_INJECTION_FAILED:
            default:
                Slog.w(TAG, "Input event injection from pid " + pid + " failed.");
                return false;
        }
    }