截屏--安卓实现应用内截屏保存在SD卡

项目老大让做把截屏的功能做到项目里边，这两天做了很多的准备，参考了不少的资料，准备分享一下

话不多说，先做一个model实现截屏的功能

实现是一个实现截图保存的类Shotter

/**
 * Created by alongstorm on 17-12-26.
 */
public class Shotter {

    //使用软引用有利于尽可能的避免内存泄漏
    private final SoftReference mRefContext;
    private ImageReader mImageReader;

    private MediaProjection mMediaProjection;
    private VirtualDisplay mVirtualDisplay;

    private String mLocalUrl = "";

    private OnShotListener mOnShotListener;


    public Shotter(Context context, Intent data) {
        this.mRefContext = new SoftReference<>(context);

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {


            mMediaProjection = getMediaProjectionManager().getMediaProjection(Activity.RESULT_OK,
                    data);

            mImageReader = ImageReader.newInstance(
                    getScreenWidth(),
                    getScreenHeight(),
                    PixelFormat.RGBA_8888,//此处必须和下面 buffer处理一致的格式 ，RGB_565在一些机器上出现兼容问题。
                    1);
        }
    }


    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    private void virtualDisplay() {

        mVirtualDisplay = mMediaProjection.createVirtualDisplay("screen-mirror",
                getScreenWidth(),
                getScreenHeight(),
                Resources.getSystem().getDisplayMetrics().densityDpi,
                DisplayManager.VIRTUAL_DISPLAY_FLAG_AUTO_MIRROR,
                mImageReader.getSurface(), null, null);

    }

    public void startScreenShot(OnShotListener onShotListener, String loc_url) {
        mLocalUrl = loc_url;
        startScreenShot(onShotListener);
    }


    @TargetApi(Build.VERSION_CODES.KITKAT)
    public void startScreenShot(OnShotListener onShotListener) {

        mOnShotListener = onShotListener;

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {

            virtualDisplay();

            Handler handler = new Handler();

            handler.postDelayed(() -> {
                Image image = mImageReader.acquireLatestImage();
                AsyncTaskCompat.executeParallel(new SaveTask(), image);
            }, 300);

        }

    }


    public class SaveTask extends AsyncTask, Void, Bitmap> {

        @TargetApi(Build.VERSION_CODES.KITKAT)
        @Override
        protected Bitmap doInBackground(Image... params) {

            if (params == null || params.length < 1 || params[0] == null) {

                return null;
            }

            Image image = params[0];

            int width = image.getWidth();
            int height = image.getHeight();
            final Image.Plane[] planes = image.getPlanes();
            final ByteBuffer buffer = planes[0].getBuffer();
            //每个像素的间距
            int pixelStride = planes[0].getPixelStride();
            //总的间距
            int rowStride = planes[0].getRowStride();
            int rowPadding = rowStride - pixelStride * width;
            Bitmap bitmap = Bitmap.createBitmap(width + rowPadding / pixelStride, height,
                    Bitmap.Config.ARGB_8888);//虽然这个色彩比较费内存但是 兼容性更好
            bitmap.copyPixelsFromBuffer(buffer);
            bitmap = Bitmap.createBitmap(bitmap, 0, 0, width, height);
            image.close();
            File fileImage = null;
            if (bitmap != null) {
                try {

                    if (TextUtils.isEmpty(mLocalUrl)) {
                        mLocalUrl = Environment.getExternalStorageDirectory().getAbsolutePath()
                        //getContext().getExternalFilesDir("screenshot").getAbsoluteFile()
                                +
                                "/"
                                +
                                SystemClock.currentThreadTimeMillis() + "666.png";
                    }
                    fileImage = new File(mLocalUrl);

                    if (!fileImage.exists()) {
                        fileImage.createNewFile();
                    }
                    FileOutputStream out = new FileOutputStream(fileImage);
                    if (out != null) {
                        bitmap.compress(Bitmap.CompressFormat.PNG, 100, out);
                        out.flush();
                        out.close();
                    }

                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                    fileImage = null;
                } catch (IOException e) {
                    e.printStackTrace();
                    fileImage = null;
                }
            }

            if (fileImage != null) {
                return bitmap;
            }
            return null;
        }

        @TargetApi(Build.VERSION_CODES.KITKAT)
        @Override
        protected void onPostExecute(Bitmap bitmap) {
            super.onPostExecute(bitmap);

            if (bitmap != null && !bitmap.isRecycled()) {
                bitmap.recycle();
            }

            if (mVirtualDisplay != null) {
                mVirtualDisplay.release();
            }

            if (mOnShotListener != null) {
                mOnShotListener.onFinish();
            }

        }
    }


    private MediaProjectionManager getMediaProjectionManager() {

        return (MediaProjectionManager) getContext().getSystemService(
                Context.MEDIA_PROJECTION_SERVICE);
    }

    private Context getContext() {
        return mRefContext.get();
    }


    private int getScreenWidth() {
        return Resources.getSystem().getDisplayMetrics().widthPixels;
    }

    private int getScreenHeight() {
        return Resources.getSystem().getDisplayMetrics().heightPixels;
    }


    // a  call back listener
    public interface OnShotListener {
        void onFinish();
    }
}

代码相信都能看懂

然后就是写一个调用截屏的Activity

public class ScreenShotActivity extends Activity {

    public static final int REQUEST_MEDIA_PROJECTION = 0x2893;


    @Override
    protected void onCreate(Bundle savedInstanceState) {

        setTheme(android.R.style.Theme_Dialog);//这个在这里设置 之后导致 的问题是 背景很黑
        super.onCreate(savedInstanceState);

        //如下代码 只是想 启动一个透明的Activity 而上一个activity又不被pause
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setBackgroundDrawable(new ColorDrawable(android.graphics.Color.TRANSPARENT));
        getWindow().setDimAmount(0f);

        requestScreenShot();
    }


    @SuppressLint("WrongConstant")
    public void requestScreenShot() {
        if (Build.VERSION.SDK_INT >= 21) {
            startActivityForResult(
                    ((MediaProjectionManager) getSystemService("media_projection")).createScreenCaptureIntent(),
                    REQUEST_MEDIA_PROJECTION
            );
        } else {
            toast("版本过低,无法截屏");
        }
    }

    private void toast(String str) {
        Toast.makeText(ScreenShotActivity.this, str, Toast.LENGTH_LONG).show();
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            case REQUEST_MEDIA_PROJECTION: {
                if (resultCode == -1 && data != null) {
                    Shotter shotter = new Shotter(ScreenShotActivity.this, data);
                    shotter.startScreenShot(() -> {
                        toast("完成!");
                        finish(); // don't forget finish activity
                    });
                }
            }
            default:
                break;
        }
    }


}

以上就是需要使用的model了，下面开始说一下怎么用，

compile project(':libshot')

首先把这个写到依赖里边

然后就是清单文件添加权限

android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

然后声明一下需要调用的model的Activity

android:name="com.androidyuan.lib.screenshot.ScreenShotActivity"
    android:theme="@android:style/Theme.Dialog" />

然后在需要的地方去调用

startActivity(new Intent(MainActivity.this, ScreenShotActivity.class));

是不是炒鸡简单，但是这么玩只能在安卓5.0以后，诶！

4.4的用户至今仍然不想放弃啊