如何将谷歌地图设置为位图图像的背景

Question

我正在研究需要在谷歌地图上添加绘图功能的项目。 我的问题是在我试图将图像保存在外部存储器中绘制谷歌地图后。它保存在内存中，但无法获得谷歌地图的背景。

这是保存按钮后创建的图像，我有当前位置按钮，编辑按钮，谷歌文本但不是地图：

这是我的xml文件。

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/map_layout">
<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="horizontal">

    <EditText
        android:id="@+id/map_search"
        android:layout_width="150dp"
        android:layout_height="wrap_content"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:hint="search....."
        android:textColor="@android:color/black"
        android:textStyle="bold"
        android:visibility="visible"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        />
    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="right"
        android:onClick="geoLocate"
        android:text="GO" />

    <ImageButton
        android:id="@+id/exit_edit_mode"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/exit_button"
        android:background="@null"
        android:layout_marginTop="8dp"
        android:layout_marginRight="10dp"
        android:layout_marginLeft="10dp"
       />


    <ImageButton
        android:id="@+id/save_button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/save_32"
        android:background="@null"
        android:layout_marginTop="8dp"
        android:layout_marginRight="10dp"

        />

</LinearLayout>
<FrameLayout
    android:id="@+id/signature"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">   
    <fragment
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="com.google.android.gms.maps.MapFragment"
        android:id="@+id/mapFragment"/>
    <ImageButton
        android:id="@+id/edit_map"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/edit_button"
        android:background="@null"
        android:layout_marginLeft="320dp"
        android:layout_marginTop="430dp"/>

</FrameLayout>
</LinearLayout>

这是我的地图活动代码，我称之为sava方法。

private void drawOnMap() {
        mcontent = (FrameLayout) findViewById(signature);
        save_button = (ImageButton) findViewById(R.id.save_button);
        exit_edit_mode = (ImageButton) findViewById(R.id.exit_edit_mode);
        mSignature = new signature(this, null);
        mcontent.addView(mSignature);

        save_button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mSignature.save();
            }
        });
        exit_edit_mode.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                mSignature.clear();
                mcontent.removeView(mSignature);
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);
            }
        });
    }

这里我定义了从地图活动中调用的保存方法

 public void save() {
        Bitmap returnedBitmap = Bitmap.createBitmap(mcontent.getWidth(),
                mcontent.getHeight(),Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(returnedBitmap);
        Drawable bgDrawable = mcontent.getBackground();
        if (bgDrawable != null)
            bgDrawable.draw(canvas);
        else
            canvas.drawColor(Color.MAGENTA);
        mcontent.draw(canvas);

        ByteArrayOutputStream baso=null;
        File file=null;
        try{
            String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
                    Locale.getDefault()).format(new Date());
            // compress and write output stream

            baso=new ByteArrayOutputStream();
            returnedBitmap.compress(Bitmap.CompressFormat.JPEG,40,baso);

            file=new File(Environment.getExternalStorageDirectory().getAbsoluteFile()+file.separator+"pictures/"+timeStamp+".JPEG");
            file.createNewFile();

            FileOutputStream fos=new FileOutputStream(file);
            fos.write(baso.toByteArray());
            fos.close();
            Toast.makeText(signature.this.getContext(), "Map Saved to memory", Toast.LENGTH_LONG).show();
        }catch(Exception e){
            e.printStackTrace();
        }
    }

这就是我在谷歌地图上画画的方式：

这是我的签名课，它帮助我在谷歌地图上做免费的手绘。

public class signature extends View {
    static final float STROKE_WIDTH = 10f;
    static final float HALF_STROKE_WIDTH = STROKE_WIDTH / 2;

    Paint paint = new Paint();
    Path path = new Path();

    float lastTouchX;
    float lastTouchY;
    final RectF dirtyRect = new RectF();

    public signature(Context context, AttributeSet attrs) {
        super(context, attrs);
        paint.setAntiAlias(true);
        paint.setColor(Color.GREEN);
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeJoin(Paint.Join.ROUND);
        paint.setStrokeWidth(STROKE_WIDTH);
    }

    public void clear() {
        path.reset();
        invalidate();
    }

    public void save() {
        Bitmap returnedBitmap = Bitmap.createBitmap(mcontent.getWidth(),
                mcontent.getHeight(),Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(returnedBitmap);
        Drawable bgDrawable = mcontent.getBackground();
        System.out.println("#######################"+bgDrawable);
        if (bgDrawable != null)
            bgDrawable.draw(canvas);
        else
            canvas.drawColor(Color.WHITE);
        mcontent.draw(canvas);

        ByteArrayOutputStream baso=null;
        File file=null;
        try{
            String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
                    Locale.getDefault()).format(new Date());
            // compress and write output stream

            System.out.println("@@@@@@@@@@@@@@@@"+timeStamp);
            baso=new ByteArrayOutputStream();
            returnedBitmap.setHasAlpha(true);
            returnedBitmap.compress(Bitmap.CompressFormat.JPEG,40,baso);

            file=new File(Environment.getExternalStorageDirectory().getAbsoluteFile()+file.separator+"pictures/"+timeStamp+".JPEG");
            file.createNewFile();

            FileOutputStream fos=new FileOutputStream(file);
            fos.write(baso.toByteArray());
            fos.close();
            Toast.makeText(signature.this.getContext(), "Map Saved to memory", Toast.LENGTH_LONG).show();
            /*Intent intent = new Intent();
            intent.putExtra("byteArray", baso.toByteArray());
            setResult(1, intent);
            finish();*/
        }catch(Exception e){
            e.printStackTrace();
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        canvas.drawPath(path, paint);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        float eventX = event.getX();
        float eventY = event.getY();
        //save.setEnabled(true);

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                path.moveTo(eventX, eventY);
                lastTouchX = eventX;
                lastTouchY = eventY;
                return true;

            case MotionEvent.ACTION_MOVE:
            case MotionEvent.ACTION_UP:
                resetDirtyRect(eventX, eventY);
                int historySize = event.getHistorySize();
                for (int i = 0; i < historySize; i++) {
                    float historicalX = event.getHistoricalX(i);
                    float historicalY = event.getHistoricalY(i);
                    path.lineTo(historicalX, historicalY);
                }
                path.lineTo(eventX, eventY);
                break;
        }

        invalidate((int) (dirtyRect.left - HALF_STROKE_WIDTH),
                (int) (dirtyRect.top - HALF_STROKE_WIDTH),
                (int) (dirtyRect.right + HALF_STROKE_WIDTH),
                (int) (dirtyRect.bottom + HALF_STROKE_WIDTH));

        lastTouchX = eventX;
        lastTouchY = eventY;

        return true;
    }

    private void resetDirtyRect(float eventX, float eventY) {
        dirtyRect.left = Math.min(lastTouchX, eventX);
        dirtyRect.right = Math.max(lastTouchX, eventX);
        dirtyRect.top = Math.min(lastTouchY, eventY);
        dirtyRect.bottom = Math.max(lastTouchY, eventY);
    }
}

如果有人让我摆脱它，我将非常感激。 谢谢。

更新

当我尝试这种方法时，它只保存地图而不是我在谷歌地图上绘制的部分。当我在bitmap下面使用canvas时压缩它只保存地图但是当我在bitmap上面使用canvas时压缩它再次出现黑屏，如上图所示。

 public void CaptureMapScreen() {
        GoogleMap.SnapshotReadyCallback callback = new GoogleMap.SnapshotReadyCallback() {
            Bitmap bitmap;

            @Override
            public void onSnapshotReady(Bitmap snapshot) {
                // TODO Auto-generated method stub
                bitmap = snapshot;
                try {
                    FileOutputStream out = new FileOutputStream("/mnt/sdcard/"
                            + "MyMapScreen" + System.currentTimeMillis()
                            + ".png");

                    // above "/mnt ..... png" => is a storage path (where image will be stored) + name of image you can customize as per your Requirement

                    Canvas convas = new Canvas(bitmap);

                    mcontent.draw(convas);
                   // mcontent.getBackground();
                    bitmap.compress(Bitmap.CompressFormat.PNG, 90, out);

                    Toast.makeText(getContext(),"map saved",Toast.LENGTH_SHORT).show();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        };

        mGoogleMap.snapshot(callback);

    }