Android系统添加自定义鼠标样式通过按键切换实例详解

一、APP通过View修改鼠标样式

app view上修改鼠标样式比较简单，通过 hover event 获取鼠标坐标并使用如下方法修改为自定义图片：

getWindow().getDecorView().setPointerIcon(PointerIcon.load(getResources(), R.drawable.pointer_spot_touch_icon));

imageView = (ImageView) findViewById(R.id.image_view);
    imageView.setOnHoverListener(new View.OnHoverListener() {
      @SuppressLint({"SetTextI18n", "ResourceType"})
      @Override
      public boolean onHover(View v, MotionEvent event) {
        int what = event.getAction();

        textX.setText("X : " + event.getX());
        textY.setText("Y : " + event.getY());

        switch(what){
          case MotionEvent.ACTION_HOVER_ENTER: //鼠标进入view
            Log.i(TAG, "bottom ACTION_HOVER_ENTER...");
            mOrgPI = getWindow().getDecorView().getPointerIcon();
            getWindow().getDecorView().setPointerIcon(PointerIcon.load(getResources(), R.drawable.pointer_spot_touch_icon));
            break;
          case MotionEvent.ACTION_HOVER_MOVE: //鼠标在view上
            Log.i(TAG, "bottom ACTION_HOVER_MOVE...");
            break;
          case MotionEvent.ACTION_HOVER_EXIT: //鼠标离开view
            Log.i(TAG, "bottom ACTION_HOVER_EXIT...");
            getWindow().getDecorView().setPointerIcon(mOrgPI);
            break;
        }
        return false;
      }
    });
  }

其中pointer_spot_touch_icon.xml 需要声明为 pointer-icon ：

<?xml version="1.0" encoding="utf-8"?>
<pointer-icon xmlns:android="http://schemas.android.com/apk/res/android"
  android:bitmap="@drawable/pointer_red_dot_arrow"
  android:hotSpotX="6dp"
  android:hotSpotY="6dp" />

但是app修改鼠标样式的view关闭后，鼠标样式会恢复成默认的黑箭头，因此不依赖APP去动态切换鼠标样式需要在framework层修改系统源码实现。

二、framework层添加自定义鼠标样式并通过按键切换

（1）添加自定义样式资源

系统图标资源在 frameworks/base/core/res/res/drawable-mdpi/ 目录，其中 pointer_arrow.png、pointer_arrow_large.png 是系统默认的黑色箭头，

pointer_arrow_red_dot.png、pointer_arrow_red_dot_large.png 是自己添加的红点样式图片：

然后在 frameworks/base/core/res/res/drawable/ 目录添加对应的xml:

pointer_arrow_red_dot_icon.xml

<?xml version="1.0" encoding="utf-8"?>
<pointer-icon xmlns:android="http://schemas.android.com/apk/res/android"
  android:bitmap="@drawable/pointer_arrow_red_dot"
  android:hotSpotX="5dp"
  android:hotSpotY="5dp" />

pointer_arrow_red_dot_large_icon.xml

<?xml version="1.0" encoding="utf-8"?>
<pointer-icon xmlns:android="http://schemas.android.com/apk/res/android"
  android:bitmap="@drawable/pointer_arrow_red_dot_large"
  android:hotSpotX="10dp"
  android:hotSpotY="10dp" />

修改 frameworks/base/core/res/res/values/styles.xml 添加资源配置，注意名字的匹配！

修改 frameworks/base/core/res/res/values/attrs.xml  引用资源：

（2）Java 层获取资源

修改 frameworks/base/core/java/android/view/PointerIcon.java ，添加如下定义：

在 getSystemIconTypeIndex(int type) 函数中返回之前配置的资源：

（3）c++层添加对应的id并加载资源

修改 frameworks/base/core/jni/android_view_PointerIcon.h

* Pointer icon styles.
 * Must match the definition in android.view.PointerIcon.
 */
enum {
  POINTER_ICON_STYLE_CUSTOM = -1,
  POINTER_ICON_STYLE_NULL = 0,
  POINTER_ICON_STYLE_ARROW = 1000,
  POINTER_ICON_STYLE_CONTEXT_MENU = 1001,
  POINTER_ICON_STYLE_HAND = 1002,
  POINTER_ICON_STYLE_HELP = 1003,
  POINTER_ICON_STYLE_WAIT = 1004,
  POINTER_ICON_STYLE_CELL = 1006,
  POINTER_ICON_STYLE_CROSSHAIR = 1007,
  POINTER_ICON_STYLE_TEXT = 1008,
  POINTER_ICON_STYLE_VERTICAL_TEXT = 1009,
  POINTER_ICON_STYLE_ALIAS = 1010,
  POINTER_ICON_STYLE_COPY = 1011,
  POINTER_ICON_STYLE_NO_DROP = 1012,
  POINTER_ICON_STYLE_ALL_SCROLL = 1013,
  POINTER_ICON_STYLE_HORIZONTAL_DOUBLE_ARROW = 1014,
  POINTER_ICON_STYLE_VERTICAL_DOUBLE_ARROW = 1015,
  POINTER_ICON_STYLE_TOP_RIGHT_DOUBLE_ARROW = 1016,
  POINTER_ICON_STYLE_TOP_LEFT_DOUBLE_ARROW = 1017,
  POINTER_ICON_STYLE_ZOOM_IN = 1018,
  POINTER_ICON_STYLE_ZOOM_OUT = 1019,
  POINTER_ICON_STYLE_GRAB = 1020,
  POINTER_ICON_STYLE_GRABBING = 1021,

  POINTER_ICON_STYLE_SPOT_HOVER = 2000,
  POINTER_ICON_STYLE_SPOT_TOUCH = 2001,
  POINTER_ICON_STYLE_SPOT_ANCHOR = 2002,

  POINTER_ICON_STYLE_REDDOT = 10001, //增加自定义样式的枚举定义，与上面 PointerIcon.java 中的变量对应
};

修改 frameworks/base/services/core/jni/com_android_server_input_InputManagerService.cpp ，加载到自定义枚举变量对应的图片资源：

void NativeInputManager::loadAdditionalMouseResources(std::map<int32_t, SpriteIcon>* outResources,
    std::map<int32_t, PointerAnimation>* outAnimationResources) {
  JNIEnv* env = jniEnv();

  for (int iconId = POINTER_ICON_STYLE_CONTEXT_MENU; iconId <= POINTER_ICON_STYLE_REDDOT;
       ++iconId) {
    PointerIcon pointerIcon;
    loadSystemIconAsSpriteWithPointerIcon(
        env, mContextObj, iconId, &pointerIcon, &((*outResources)[iconId]));
    if (!pointerIcon.bitmapFrames.empty()) {
      PointerAnimation& animationData = (*outAnimationResources)[iconId];
      size_t numFrames = pointerIcon.bitmapFrames.size() + 1;
      animationData.durationPerFrame =
          milliseconds_to_nanoseconds(pointerIcon.durationPerFrame);
      animationData.animationFrames.reserve(numFrames);
      animationData.animationFrames.push_back(SpriteIcon(
          pointerIcon.bitmap, pointerIcon.hotSpotX, pointerIcon.hotSpotY));
      for (size_t i = 0; i < numFrames - 1; ++i) {
       animationData.animationFrames.push_back(SpriteIcon(
           pointerIcon.bitmapFrames[i], pointerIcon.hotSpotX, pointerIcon.hotSpotY));
      }
    }
  }
  loadSystemIconAsSprite(env, mContextObj, POINTER_ICON_STYLE_NULL,
      &((*outResources)[POINTER_ICON_STYLE_NULL]));
}

（4）按键切换鼠标样式

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