Android view转Bitmap（将布局文件转成Bitmap）&& Bitmap保存到本地相册

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一、view转Bitmap

1、使用LayoutInflater导入布局

View view = LayoutInflater.from(activity).inflate(R.layout.img_qrcode, null, false);
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2、测量计算view大小

		//计算设备分辨率
        WindowManager manager = activity.getWindowManager();
        DisplayMetrics metrics = new DisplayMetrics();
        manager.getDefaultDisplay().getMetrics(metrics);
        int width = metrics.widthPixels;
		int height = metrics.heightPixels;

        //测量使得view指定大小
        int measureWidth = View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY);
        int measureHeight = View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.AT_MOST);

        view.measure(measureWidth, measureHeight);
        //调用layout方法布局后，可以得到view的尺寸
        view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
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3、把view转成图片Bitmap

final Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawColor(Color.WHITE);
        view.draw(canvas);
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二、将Bitmap保存到本地相册

	/**
     * 保存bitmap到相册
     */
    private void saveBitmapToAlbum(Bitmap bitmap) {
        final File appDir = new File(activity.getExternalCacheDir(), "image");
        if (!appDir.exists()) {
            appDir.mkdir();
        }
        final String fileName = System.currentTimeMillis() + ".jpg";
        final File file = new File(appDir, fileName);
        try {
            FileOutputStream fos = new FileOutputStream(file);
            try {
                bitmap.compress(Bitmap.CompressFormat.JPEG, 90, fos);
                fos.flush();
            } finally {
                fos.close();
            }
            //把文件插入到系统相册
            MediaStore.Images.Media.insertImage(activity.getContentResolver(), file.getAbsolutePath(), fileName, null);
            //通知图库更新
            //activity.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + file.getAbsolutePath())));
            activity.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(new File(file.getPath()))));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
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三、代码实现demo

public class SaveBitmap{

    public void qrCode() {
        View view = LayoutInflater.from(activity).inflate(R.layout.img_qrcode, null, false);
		Bitmap saveBitmap = createBitmapByView(view);
		saveBitmapToAlbum(saveBitmap);
    }

    /**
     * view转bitmap
     *
     * @param view view
     * @return Bitmap
     */
    private Bitmap createBitmapByView(View view) {
        //计算设备分辨率
        WindowManager manager = activity.getWindowManager();
        DisplayMetrics metrics = new DisplayMetrics();
        manager.getDefaultDisplay().getMetrics(metrics);
        int width = metrics.widthPixels;
		int height = metrics.heightPixels;

        //测量使得view指定大小
        int measureWidth = View.MeasureSpec.makeMeasureSpec(width, View.MeasureSpec.EXACTLY);
        int measureHeight = View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.AT_MOST);

        view.measure(measureWidth, measureHeight);
        //调用layout方法布局后，可以得到view的尺寸
        view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());

        final Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawColor(Color.WHITE);
        view.draw(canvas);
        return bitmap;
    }

    /**
     * 保存bitmap到相册
     */
    private void saveBitmapToAlbum(Bitmap bitmap) {
        final File appDir = new File(activity.getExternalCacheDir(), "image");
        if (!appDir.exists()) {
            appDir.mkdir();
        }
        final String fileName = System.currentTimeMillis() + ".jpg";
        final File file = new File(appDir, fileName);
        try {
            FileOutputStream fos = new FileOutputStream(file);
            try {
                bitmap.compress(Bitmap.CompressFormat.JPEG, 90, fos);
                fos.flush();
            } finally {
                fos.close();
            }
            //把文件插入到系统相册
            MediaStore.Images.Media.insertImage(activity.getContentResolver(), file.getAbsolutePath(), fileName, null);
            //通知图库更新
            //activity.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.parse("file://" + file.getAbsolutePath())));
            activity.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(new File(file.getPath()))));
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}
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