android 4.4 sdk截图和jni截图实现

最新推荐文章于 2021-05-28 15:32:25 发布

原创最新推荐文章于 2021-05-28 15:32:25 发布 · 2.3k 阅读

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本文详细解析了如何在Android系统中通过服务接口实现屏幕截图，并深入探讨了在JNI层使用SurfaceControl API进行屏幕截图的具体实现方法。文章还提供了关键源码片段和调用API的解释，为开发者提供了一套完整的截图解决方案。

首先找到系统截图Service的源码

public class TakeScreenshotService extends Service

关于怎么获得系统服务见笔记:

public void handleMessage(Message msg) {
            switch (msg.what) {
                case 1:
                    final Messenger callback = msg.replyTo;
                    if (mScreenshot == null) {
                        mScreenshot = new GlobalScreenshot(TakeScreenshotService.this);
                    }
                    mScreenshot.takeScreenshot(new Runnable() {
                        @Override public void run() {
                            Message reply = Message.obtain(null, 1);
                            try {
                                callback.send(reply);
                            } catch (RemoteException e) {
                            }
                        }
                    }, msg.arg1 > 0, msg.arg2 > 0);
            }

in GlobalScreenshot.java

android 4.4以下:

void takeScreenshot(Runnable finisher, boolean statusBarVisible, boolean navBarVisible) {
        // We need to orient the screenshot correctly (and the Surface api seems to take screenshots
        // only in the natural orientation of the device :!)
//.....
        // Take the screenshot
        mScreenBitmap = Surface.screenshot((int) dims[0], (int) dims[1]);

android4.4:

void takeScreenshot(Runnable finisher, boolean statusBarVisible, boolean navBarVisible) {
        // We need to orient the screenshot correctly (and the Surface api seems to take screenshots
        // only in the natural orientation of the device :!)
...
        // Take the screenshot
        mScreenBitmap = SurfaceControl.screenshot((int) dims[0], (int) dims[1]);

SurfaceControl.screenshot((int) dims[0], (int) dims[1]);是隐藏API

怎么调用见:

如果没有源码可以上

https://github.com/CyanogenMod/android_frameworks_base

------------

如何在jni层实现截图?

参考SurfaceControl源码

bool get_sceenrgb(int width,int height){
sp<IBinder> dtoken(SurfaceComposerClient::getBuiltInDisplay(
ISurfaceComposer::eDisplayIdMain));
mScreenshot.update(dtoken, width, height);
src_32 = (uint32_t *)mScreenshot.getPixels();
size = (mScreenshot.getSize());

//获取屏幕的宽高等信息
status_t status = SurfaceComposerClient::getDisplayInfo(dtoken, &dinfo);
printf("w=%d,h=%d,xdpi=%f,ydpi=%f,fps=%f,ds=%f \n",
dinfo.w, dinfo.h, dinfo.xdpi, dinfo.ydpi, dinfo.fps, dinfo.density);
return true;
}

由于我只需要它的像素信息.所以没有保存为图片....完整的实现应该构造一个 SkBitmap对象保存