我试图在背景中绘制网格（仅8x8行），但我的绘图视图覆盖了它，并且网格没有显示出来。我的DrawingView处理触摸和绘制圆圈。网格必须在后台绘制网格（当DrawingView消失时它会这样做。）
MainActivity.java：
public class MainActivity extends AppCompatActivity {
private RelativeLayout layout;
private DrawingView drawingView;
private FloatingActionButton pickPhoto;
private final int SELECT_PHOTO = 1;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
layout = (RelativeLayout) findViewById(R.id.layout);
pickPhoto = (FloatingActionButton) findViewById(R.id.insertPhoto);
drawingView = (DrawingView) findViewById(R.id.drawingView);
assert drawingView != null;
drawingView.getHolder().setFormat(PixelFormat.TRANSLUCENT);
pickPhoto.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
photoPickerIntent.setType("image/*");
startActivityForResult(photoPickerIntent, SELECT_PHOTO);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
menu.add(0, 0, 0, "Save")
.setIcon(R.drawable.ic_save)
.setOnMenuItemClickListener(new MenuItem.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(MenuItem item) {
FloatingActionMenu fab = (FloatingActionMenu) findViewById(R.id.fab);
assert fab != null;
fab.setVisibility(View.GONE);
Bitmap bitmap = getBitmap(layout);
saveChart(bitmap, layout.getMeasuredHeight(), layout.getMeasuredWidth());
fab.setVisibility(View.VISIBLE);
return false;
}
})
.setShowAsAction(
MenuItem.SHOW_AS_ACTION_ALWAYS
| MenuItem.SHOW_AS_ACTION_WITH_TEXT);
return super.onCreateOptionsMenu(menu);
}
public void saveChart(Bitmap getbitmap, float height, float width) {
File folder = new File(Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
"My drawings");
if (!folder.exists()) {
folder.mkdirs();
}
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
Locale.getDefault()).format(new Date());
File file = new File(folder.getPath() + File.separator + "/" + timeStamp + ".png");
if (!file.exists()) {
try {
file.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
FileOutputStream ostream;
try {
ostream = new FileOutputStream(file);
Bitmap save = Bitmap.createBitmap((int) width, (int) height, Bitmap.Config.ARGB_8888);
Paint paint = new Paint();
paint.setColor(Color.WHITE);
Canvas now = new Canvas(save);
now.drawRect(new Rect(0, 0, (int) width, (int) height), paint);
now.drawBitmap(getbitmap,
new Rect(0, 0, getbitmap.getWidth(), getbitmap.getHeight()),
new Rect(0, 0, (int) width, (int) height), null);
save.compress(Bitmap.CompressFormat.PNG, 100, ostream);
} catch (NullPointerException | FileNotFoundException e) {
e.printStackTrace();
}
}
public Bitmap getBitmap(RelativeLayout layout) {
layout.setDrawingCacheEnabled(true);
layout.buildDrawingCache();
Bitmap bmp = Bitmap.createBitmap(layout.getDrawingCache());
layout.setDrawingCacheEnabled(false);
return bmp;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) {
super.onActivityResult(requestCode, resultCode, imageReturnedIntent);
switch (requestCode) {
case SELECT_PHOTO:
if (resultCode == RESULT_OK) {
try {
final Uri imageUri = imageReturnedIntent.getData();
final InputStream imageStream = getContentResolver().openInputStream(imageUri);
final Bitmap selectedImage = BitmapFactory.decodeStream(imageStream);
drawingView.setImage(selectedImage);
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}
}
}
}
DrawingView.java：
class DrawingView extends SurfaceView {
private final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
private ArrayList<Point> points;
private Bitmap mBitmap;
public DrawingView(Context context, AttributeSet attrs) {
super(context, attrs);
paint.setColor(Color.RED);
paint.setStyle(Paint.Style.FILL);
setFocusable(true);
setFocusableInTouchMode(true);
points = new ArrayList<>();
setBackgroundColor(Color.WHITE);
}
@Override
protected void onDraw(Canvas canvas) {
if (mBitmap != null)
canvas.drawBitmap(mBitmap, 0, 0, paint);
for (Point p : points)
canvas.drawCircle(p.x, p.y, 50, paint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
points.add(new Point((int) event.getX(), (int) event.getY()));
invalidate();
return false;
}
public void setImage(Bitmap bitmap) {
mBitmap = bitmap;
invalidate();
}
}
Grid.java：
public class Grid extends View{
private int rowsCount = 8;
private int columnsCount = 8;
private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
public Grid(Context context, AttributeSet attrs) {
super(context, attrs);
paint.setColor(Color.BLACK);
}
@Override
protected void onDraw(Canvas canvas) {
int height = getHeight();
int width = getWidth();
for (int i = 0; i < rowsCount; ++i) {
canvas.drawLine(0, height / rowsCount * (i + 1), width, height / rowsCount * (i + 1), paint);
}
for (int i = 0; i < columnsCount; ++i) {
canvas.drawLine(width / columnsCount * (i + 1), 0, width / columnsCount * (i + 1), height, paint);
}
super.onDraw(canvas);
}
}
activity_main.xml中：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:fab="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/layout"
tools:context=".MainActivity"
android:orientation="vertical">
<reminder.com.paint.Grid
android:id="@+id/grid"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<reminder.com.paint.DrawingView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/drawingView"
android:background="#00FFFFFF"
android:layout_alignParentEnd="true" />
</RelativeLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.github.clans.fab.FloatingActionMenu
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="10dp"
android:layout_marginLeft="10dp"
fab:menu_fab_size="normal"
fab:menu_showShadow="true"
fab:menu_shadowColor="#66000000"
fab:menu_shadowRadius="4dp"
fab:menu_shadowXOffset="1dp"
fab:menu_shadowYOffset="3dp"
fab:menu_colorNormal="#DA4336"
fab:menu_colorPressed="#E75043"
fab:menu_colorRipple="#99f47070"
fab:menu_animationDelayPerItem="50"
fab:menu_icon="@drawable/fab_add"
fab:menu_buttonSpacing="0dp"
fab:menu_labels_margin="0dp"
fab:menu_labels_showAnimation="@anim/fab_slide_in_from_right"
fab:menu_labels_hideAnimation="@anim/fab_slide_out_to_right"
fab:menu_labels_paddingTop="4dp"
fab:menu_labels_paddingRight="8dp"
fab:menu_labels_paddingBottom="4dp"
fab:menu_labels_paddingLeft="8dp"
fab:menu_labels_padding="8dp"
fab:menu_labels_textColor="#FFFFFF"
fab:menu_labels_textSize="14sp"
fab:menu_labels_cornerRadius="3dp"
fab:menu_labels_colorNormal="#333333"
fab:menu_labels_colorPressed="#444444"
fab:menu_labels_colorRipple="#66FFFFFF"
fab:menu_labels_showShadow="true"
fab:menu_labels_singleLine="false"
fab:menu_labels_ellipsize="none"
fab:menu_labels_maxLines="-1"
fab:menu_labels_position="left"
fab:menu_openDirection="up"
fab:menu_backgroundColor="@android:color/transparent"
android:layout_alignParentBottom="true"
android:layout_alignParentEnd="true"
android:layout_gravity="end">
<com.github.clans.fab.FloatingActionButton
android:id="@+id/insertPhoto"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_insert_photo_24dp"
fab:fab_size="mini"
fab:fab_label="Add photos" />
<com.github.clans.fab.FloatingActionButton
android:id="@+id/addCircle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_brightness_1_24dp"
fab:fab_size="mini"
fab:fab_label="Add circles" />
</com.github.clans.fab.FloatingActionMenu>
</RelativeLayout>