Android: Screencap to bytes directly - Skip saving to file

问题

I use the following code to take screenshot on a rooted device:

    sh =  Runtime.getRuntime().exec("su", null,null);
    os = sh.getOutputStream();
    os.write(("/system/bin/screencap -p " + "/sdcard/img.jpg" + "\n").getBytes("ASCII"));
    os.flush();
    os.close();
    sh.waitFor();
    myBitmap = BitmapFactory.decodeFile("/sdcard/img.jpg");

As i want to take screenshots frequently, I don't want to first save it to the file and then read the bytes. Is there a better way to get the screenshot bitmap directly? I just wan't to eliminate this unnecessary delay. Thanks a lot!

Update:

The screencap.cpp code can be viewed here.

Also, it mentions this:

    "usage: %s [-hp] [-d display-id] [FILENAME]\n"
    " -h: this message\n"
    " -p: save the file as a png.\n"
    " -d: specify the display id to capture, default %d.\n"
    "If FILENAME ends with .png it will be saved as a png.\n"
    "If FILENAME is not given, the results will be printed to stdout.\n"

Please help me out. Thanks!

回答1:

This will work unless you're on 8.1 Pixel2 XL, then you get a security exception.

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

import java.io.IOException;
import java.io.OutputStreamWriter;

public class BitmapScreencap {
    public final static BitmapScreencap Get = new BitmapScreencap();
    private BitmapScreencap() { }
    public Bitmap Screen() {
        try {
            Process process = Runtime.getRuntime().exec("su");
            OutputStreamWriter outputStream = new OutputStreamWriter(process.getOutputStream());
            outputStream.write("/system/bin/screencap -p\n");
            outputStream.flush();
            Bitmap screen = BitmapFactory.decodeStream(process.getInputStream());
            outputStream.write("exit\n");
            outputStream.flush();
            outputStream.close();
            return screen;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}

Place anywhere in your code to get bitmap

BitmapScreencap.Get.Screen();

来源：https://stackoverflow.com/questions/23313412/android-screencap-to-bytes-directly-skip-saving-to-file

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java

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screen-capture