我正在尝试使用Canvas在我的活动中使用Canvas绘制草图，其中图像通过拍摄活动来填充图像。我已经指定了Ontouchlistner来绘制触摸位置上的图像，但是我没有准确地触摸听众。也就是说，当我触摸显示屏时，草图会在不在我触摸位置的另一个地方创建。
public class MainActivity extends AppCompatActivity implements SaveAction, View.OnTouchListener {
private ImageView image;
private static final int CAMERA_REQUEST = 1888;
final Context context = this;
Bitmap alterdbitmap;
Internet_checking mconnectionchecking;
AlertDialog ald;
public static final int MEDIA_TYPE_IMAGE = 1;
private static final String IMAGE_DIRECTORY_NAME = "View Share";
private Uri fileUri;
FloatingActionButton fab,fab1;
Canvas canvas;
Paint paint;
Matrix matrix;
float downx = 0;
float downy = 0;
float upx = 0;
float upy = 0;
RelativeLayout rlayout;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
image = (ImageView) findViewById(R.id.img);
rlayout = (RelativeLayout)findViewById(R.id.rltive1);
camera();
}
@Override
protected void onResume() {
super.onResume();
functionality();
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == CAMERA_REQUEST) {
if (resultCode == RESULT_OK) {
// Bitmap photo = (Bitmap) data.getExtras().get("data");
// image.setImageBitmap(photo);
previewimage();
} else if (resultCode == RESULT_CANCELED) {
AlertDialog.Builder alert = new AlertDialog.Builder(context);
alert.setTitle("Error");
alert.setCancelable(false);
alert.setMessage("NO IMAGE FOUND");
alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
Intent intent = getIntent();
overridePendingTransition(0, 0);
intent.addFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
finish();
overridePendingTransition(0, 0);
startActivity(intent);
}
});
ald = alert.create();
ald.show();
} else {
Toast.makeText(getApplicationContext(),
"Sorry! Failed to capture image", Toast.LENGTH_LONG)
.show();
}
}
}
@TargetApi(23)
private void previewimage() {
try {
image.setVisibility(View.VISIBLE);
BitmapFactory.Options options = new BitmapFactory.Options();
// options.inSampleSize = 8;
final Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath(), options);
alterdbitmap = Bitmap.createBitmap(bitmap.getWidth(),bitmap.getHeight(),bitmap.getConfig());
canvas = new Canvas(alterdbitmap);
paint = new Paint();
paint.setColor(Color.parseColor("#FF5722"));
paint.setStrokeWidth(5);
matrix = new Matrix();
canvas.drawBitmap(bitmap, matrix, paint);
image.setImageBitmap(alterdbitmap);
image.setOnTouchListener(this);
// rlayout.setOnTouchListener(this);
} catch (Exception e) {
e.printStackTrace();
}
}
// @Override
// public boolean onCreateOptionsMenu(Menu menu) {
// // Inflate the menu; this adds items to the action bar if it is present.
// getMenuInflater().inflate(R.menu.menu_main, menu);
// return true;
// }
//
// @Override
// public boolean onOptionsItemSelected(MenuItem item) {
// // Handle action bar item clicks here. The action bar will
// // automatically handle clicks on the Home/Up button, so long
// // as you specify a parent activity in AndroidManifest.xml.
// int id = item.getItemId();
//
// //noinspection SimplifiableIfStatement
// if (id == R.id.action_settings) {
// return true;
// }
//
// return super.onOptionsItemSelected(item);
// }
private void functionality() {
fab1=(FloatingActionButton)findViewById(R.id.fab1);
fab = (FloatingActionButton)findViewById(R.id.fab);
// mbtn = (Button) findViewById(R.id.btn1);
mconnectionchecking = new Internet_checking(this);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (mconnectionchecking.isNetworkAvailable() == true) {
final File photoFile = new File(getFilesDir(), String.valueOf(image));
Intent nt = new Intent(Intent.ACTION_SEND, Uri.fromFile(photoFile));
String title = getResources().getString(R.string.Share_Via);
Intent chooser = Intent.createChooser(nt, title);
startActivity(chooser);
} else {
AlertDialog.Builder at = new AlertDialog.Builder(context);
at.setTitle("Connection Error");
at.setCancelable(true);
at.setMessage("Internet connection required");
at.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
startActivity(new Intent(Settings.ACTION_SETTINGS));
}
});
ald = at.create();
ald.show();
}
}
});
fab1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
camera();
}
});
}
private void camera(){
Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE);
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
@Override
public void onBackPressed() {
moveTaskToBack(true);
}
public Uri getOutputMediaFileUri(int type) {
return Uri.fromFile(getOutputMediaFile(type));
}
private static File getOutputMediaFile(int type) {
// External sdcard location
File mediaStorageDir = new File(
Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
IMAGE_DIRECTORY_NAME);
// Create the storage directory if it does not exist
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d(IMAGE_DIRECTORY_NAME, "Oops! Failed create "
+ IMAGE_DIRECTORY_NAME + " directory");
return null;
}
}
// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
Locale.getDefault()).format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator
+ "IMG_" + timeStamp + ".jpg");
} else {
return null;
}
return mediaFile;
}
@Override
public void autosave() {
}
@Override
public boolean onTouch(View view, MotionEvent event) {
int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
downx = event.getX();
downy = event.getY();
break;
case MotionEvent.ACTION_MOVE:
upx = event.getX();
upy = event.getY();
canvas.drawLine(downx, downy, upx, upy, paint);
image.invalidate();
downx = upx;
downy = upy;
break;
case MotionEvent.ACTION_UP:
upx = event.getX();
upy = event.getY();
canvas.drawLine(downx, downy, upx, upy, paint);
image.invalidate();
break;
case MotionEvent.ACTION_CANCEL:
break;
default:
break;
}
return true;
}
}
activity_main.xml中
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#e0080809"
tools:context="mypckage name.MainActivity">
<RelativeLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/rltive1">
<ImageView
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:id="@+id/img"
android:scaleType="fitXY"
android:layout_alignParentTop="true" />
<!--<Button-->
<!--android:layout_width="50dp"-->
<!--android:layout_height="50dp"-->
<!--android:id="@+id/btn1"-->
<!--android:layout_alignParentTop="true"-->
<!--android:layout_alignParentRight="true"-->
<!--android:layout_alignParentEnd="true"-->
<!--android:background="@drawable/share"/>-->
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
app:elevation="6dp"
app:backgroundTint="@color/colorAccent"
app:pressedTranslationZ="12dp"
android:src="@drawable/ic_share_white_24dp" />
<android.support.design.widget.FloatingActionButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:elevation="6dp"
app:backgroundTint="@color/colorAccent"
app:pressedTranslationZ="12dp"
android:layout_marginRight="10dp"
android:layout_marginEnd="4dp"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:src="@drawable/ic_add_a_photo_white_24dp"
android:id="@+id/fab1"/>
</RelativeLayout>
</RelativeLayout>
答案 0 :(得分：0)
在您的活动类中使用自定义imageview，如下所示：
public class DrawImageView extends LinearLayout {
Paint paint = new Paint();
Point point = new Point();
Uri uri;
Context myContext;
public DrawImageView(Context context, Uri imageUri) {
super(context);
uri = imageUri;
myContext = context;
paint.setColor(Color.RED);
paint.setStrokeWidth(5);
paint.setStyle(Paint.Style.STROKE);
try {
InputStream inputStream = context.getContentResolver().openInputStream(imageUri);
this.setBackground(Drawable.createFromStream(inputStream, imageUri.toString()));
} catch (FileNotFoundException ignored) {
}
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawRect(point.x - 10, point.y - 10, point.x + 10, point.y + 10, paint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
point.x = event.getX();
point.y = event.getY();
}
invalidate();
return true;
}
class Point {
float x, y;
}
}
这只是一个例子。在onDraw方法中实现你的逻辑。