Develop Reference

how to draw a curved line with my finger?

I want to draw curved line in android studio without ArrayList.
I know how to draw with Arraylist, but I just want to know without Arraylist.
Anyhow, I want to draw curved line a set length without use Arraylist. How can I do this?
Here is my code but it doesn't work well.
package com.example.final_practice3;
import...
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new MyView(this));
}
private class MyView extends View {
private int count = 0;
private int[][] points = new int[500][2]; //point x, y in array to 500size
public MyView(Context context) {
super(context);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
//first point
points[0][0] = (int) getX();
points[0][1] = (int) getY();
break;
case MotionEvent.ACTION_MOVE:
//When finger is moving, save to points array
for (int i = 1; i < 500; i++) {
points[i][0] = (int) event.getX();
points[i][1] = (int) event.getY();
count++;
}
break;
case MotionEvent.ACTION_UP:
//When finger is up, draw the curved line
this.invalidate();
break;
}
return true;
}
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Paint paint = new Paint();
paint.setColor(Color.RED);
paint.setStrokeWidth(5);
paint.setAntiAlias(true);
//draw curved line with points array
for (int i = 1; i < 500; i++) {
canvas.drawLine(points[i - 1][0], points[i - 1][1], points[i][0],points[i][1],paint);
}
}
}
}

create rototable circle in android using Canvas

Guys I know How to draw circle in android..But what I need is using onTouch method to rotate that circle depending on the user hand movement on that circle. Please help.
public class MainActivity extends Activity {
public class SampleView extends View {
Paint mPaint = new Paint();
private Animation anim;
public SampleView(Context context) {
super(context);
mPaint.setStyle(Paint.Style.FILL);
mPaint.setStrokeWidth(10);
mPaint.setColor(Color.RED);
}
private void createAnimation(Canvas canvas) {
anim = new RotateAnimation(0, 360, getWidth()/2, getHeight()/2);
anim.setRepeatMode(Animation.RESTART);
anim.setRepeatCount(Animation.INFINITE);
anim.setDuration(10000L);
startAnimation(anim);
}
protected void onDraw(Canvas canvas) {
int cx = getWidth()/2; // x-coordinate of center of the screen
int cy = getHeight()/2; // y-coordinate of the center of the screen
// Starts the animation to rotate the circle.
if (anim == null)
createAnimation(canvas);
canvas.drawCircle(cx, cy, 150, mPaint); // drawing the circle.
}
}
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new SampleView(this));
}
}

First, we have to determine the angle between old and new position of circle (as below figure).
cos a = uv / (|u|*|v|)
The simple equation may be
double tx = touch_x - center_x, ty = touch_y - center_y;
double t_length = Math.sqrt(tx*tx + ty*ty);
double angle = Math.acos(ty / t_length);
Then to rotate your Canvas. you can use the code
canvas.rotate(angle);
Or you can use another method as
public int touch_x,touch_y,cx,cy;
public float angle=0;
#Override
public boolean onTouchEvent(MotionEvent event) {
touch_x = (int)event.getX();
touch_y = (int)event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_MOVE:
case MotionEvent.ACTION_UP:
}
//double tx = touch_x - cx, ty = touch_y - cy;
// double t_length = Math.sqrt(tx*tx + ty*ty);
//angle = (float) Math.acos(ty / t_length);
double dx = touch_x - cx;
// Minus to correct for coord re-mapping
double dy = -touch_y - cy;
double inRads = Math.atan2(dy,dx);
// We need to map to coord system when 0 degree is at 3 O'clock, 270 at 12 O'clock
if (inRads < 0)
inRads = Math.abs(inRads);
else
inRads = 2*Math.PI - inRads;
angle= (float) Math.toDegrees(inRads);
return false;
}

How to draw a line from the source to the destination of a drag and drop operation?

I've implemented a drag and drop system and now I want to draw a line from the source to destination. How can I draw that line? I already used an extension of the View class, but it's not working. Here is my code:
public class TempDDActivity extends Activity implements OnTouchListener {
/** Called when the activity is first created. */
private View selected_item = null;
private int offset_x = 0;
private int offset_y = 0;
Boolean touchFlag=false;
boolean dropFlag=false;
LayoutParams imageParams;
ImageView imageDrop,image1,image2;
int crashX,crashY;
Drawable dropDrawable,selectDrawable;
Rect dropRect,selectRect;
int topy,leftX,rightX,bottomY;
int dropArray[];
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);
ViewGroup container = (ViewGroup) findViewById(R.id.container);
imageDrop=(ImageView) findViewById(R.id.ImgDrop);
image1=(ImageView) findViewById(R.id.img);
image2=(ImageView) findViewById(R.id.img2);
container.setOnTouchListener(new View.OnTouchListener()
{
public boolean onTouch(View v, MotionEvent event)
{
if(touchFlag==true)
{
System.err.println("Display If Part ::->"+touchFlag);
switch (event.getActionMasked())
{
case MotionEvent.ACTION_DOWN :
topy=imageDrop.getTop();
leftX=imageDrop.getLeft();
rightX=imageDrop.getRight();
bottomY=imageDrop.getBottom();
System.err.println("Display Top-->"+topy);
System.err.println("Display Left-->"+leftX);
System.err.println("Display Right-->"+rightX);
System.err.println("Display Bottom-->"+bottomY);
//opRect.
break;
case MotionEvent.ACTION_MOVE:
crashX=(int) event.getX();
crashY=(int) event.getY();
System.err.println("Display Here X Value-->"+crashX);
System.err.println("Display Here Y Value-->"+crashY);
int x = (int) event.getX() - offset_x;
int y = (int) event.getY() - offset_y;
//int w = getWindowManager().getDefaultDisplay().getWidth() - 100;
//int h = getWindowManager().getDefaultDisplay().getHeight() - 100;
int w = getWindowManager().getDefaultDisplay().getWidth() - 50;
int h = getWindowManager().getDefaultDisplay().getHeight() - 10;
if (x > w)
x = w;
if (y > h)
y = h;
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(new ViewGroup.MarginLayoutParams( RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT));
lp.setMargins(x, y, 0, 0);
//Drop Image Here
if(crashX > leftX && crashX < rightX && crashY > topy && crashY < bottomY )
{
Drawable temp=selected_item.getBackground();
imageDrop.setBackgroundDrawable(temp);
imageDrop.bringToFront();
dropFlag=true;
selected_item.setVisibility(View.INVISIBLE);
}
//Drop Image Here
selected_item.setLayoutParams(lp);
break;
case MotionEvent.ACTION_UP:
//
touchFlag=false;
if(dropFlag==true)
{
dropFlag=false;
}
else
{
selected_item.setLayoutParams(imageParams);
}
break;
default:
break;
}
}else
{
System.err.println("Display Else Part ::->"+touchFlag);
}
return true;
}
});
image1.setOnTouchListener(this);
image2.setOnTouchListener(this);
}
public boolean onTouch(View v, MotionEvent event)
{
switch (event.getActionMasked())
{
case MotionEvent.ACTION_DOWN:
touchFlag=true;
offset_x = (int) event.getX();
offset_y = (int) event.getY();
selected_item = v;
imageParams=v.getLayoutParams();
break;
case MotionEvent.ACTION_UP:
selected_item=null;
touchFlag=false;
break;
default:
break;
}
return false;
}
}

now I want to draw a line from source to destination
First you need to have a custom view for actually drawing the line. This would be the layout that wraps the ImageViews, which in your case I think is a RelativeLayout. That class would be something like:
public class DragObserverLayout extends RelativeLayout {
float startX, startY, stopX, stopY;
private Paint mPaint = new Paint();
private List<Rect> lines = new ArrayList<Rect>();
public DragObserverLayout(Context context, AttributeSet attrs) {
super(context, attrs);
mPaint.setColor(Color.GREEN);
mPaint.setStrokeWidth(2.0f);
}
#Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
final int count = lines.size();
for (int i = 0; i < count; i++) {
final Rect r = lines.get(i);
canvas.drawLine(r.left, r.top, r.right, r.bottom, mPaint);
}
}
public void addLine(Rect r) {
lines.add(r);
invalidate();
}
}
Then in the OnTouchListener for the container where you do the drag operation you would simply do:
final int[] location = new int[2];
final DragObserverLayout container = (DragObserverLayout ) findViewById(R.id.container);
container.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if(touchFlag==true) {
switch (event.getActionMasked())
{
case MotionEvent.ACTION_DOWN :
//...
selected_item.getLocationOnScreen(location);
container.startX = location[0];
container.startY = location[1];
break;
case MotionEvent.ACTION_MOVE:
//...
selected_item.getLocationOnScreen(location);
break;
case MotionEvent.ACTION_UP:
// ...
// .. the item was dragged on the target
if (selected_item.getVisibility() != View.VISIBLE) {
Rect r = new Rect();
r.left = (int) container.startX;
r.top = (int) container.startY;
imageDrop.getLocationInWindow(location);
r.right = location[0];
r.bottom = location[1];
container.addLine(r);
}
This will draw a straight line from the initial position of the dragged ImageView(top left point of the view) to the current position until the ImageView is "dropped". If you want you could offset the start line's position to point to the real touched position by making some simple calculation in the onTouch method for the ImageViews. This also works as you have a full screen application covering the entire screen, otherwise you'll have to offset the return from getLocationOnScreen() to take in consideration the status bar. If you want to keep the line on the screen after the drag operation finishes you'll need to store it in the container.

how to set separate toast message for 2 bitmap in android?

public class Sample2 extends Activity {
private SampleView sView;
private static int displayWidth = 100; //movement area
private static int displayHeight = 100;
float angle = 0;
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
sView = new SampleView(this);
setContentView(sView);
}//oncreate
private class SampleView extends View {
Context con;
private Rect displayRect = null; //rect we display to
private int scrollRectX = 0; //current left location of scroll rect
private int scrollRectY = 0; //current top location of scroll rect
private float scrollByX = 0; //scroll by amounts
private float scrollByY = 0;
private float startX = 0; //track x from one ACTION_MOVE to the next
private float startY = 0; //track y from one ACTION_MOVE to the next
private int state = 0;
Bitmap bitmap2;
public SampleView(Context context) {
super(context);
displayRect = new Rect(0, 0, displayWidth, displayHeight);
}//constructor
public boolean onTouchEvent(MotionEvent event) {
float x;
float y;
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
//Initial down event location.
startX = event.getRawX();
startY = event.getRawY()-50;
// Log.e("TOUCHED",startY+" "+(scrollRectY+displayHeight));
if (((startX>scrollRectX)&(startX<(scrollRectX+displayWidth)))&
((startY>scrollRectY)&(startY<(scrollRectY+displayHeight)))) state = 1;
//Log.e("TOUCHED","State "+state);
break;
case MotionEvent.ACTION_MOVE:
x = event.getRawX();
y = event.getRawY()-50;
scrollByX = x - startX;
scrollByY = y - startY;
startX = x;
startY = y;
if (state != 0) invalidate(); //move it
break;
case MotionEvent.ACTION_UP:
x = event.getRawX();
y = event.getRawY()-50;
scrollByX = x - startX;
scrollByY = y - startY;
startX = x;
startY = y;
state = 0;
invalidate();
break;
}//switch
return true;
}//ontouch
protected void onDraw(Canvas canvas) {
scrollRectX = scrollRectX+(int)scrollByX;
scrollRectY = scrollRectY+(int)scrollByY;
displayRect.set(scrollRectX,scrollRectY,scrollRectX+displayWidth,
scrollRectY+displayHeight);
Paint paint = new Paint();
Bitmap bitmap1 = BitmapFactory.decodeResource(getResources(),R.drawable.ic_launcher);
bitmap2= BitmapFactory.decodeResource(getResources(),R.drawable.ic_launcher).copy(Config.RGB_565, true);
canvas.drawBitmap(bitmap2, null, displayRect, paint);
//TODO: Fill In Methods Etc.
}
}
}
i have used this code....now my question is this how to set separate toast messages for 2 bitmap in android?....if i touch in background rectangle it shows toast message and if i touch on image it shows another toast message by using if condition on ontouchevents....plz any1 can say this....

you can do like this way,
Demo.java
public class Demo extends Activity implements OnClickListener{
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.demo_layout);
final LinearLayout lin_layout = (LinearLayout) findViewById(R.id.lin_layout);
final ImageView img_view = (EditText) findViewById(R.id.img_view);
// call your touch event
l_l.setOnClickListener(this);
imageView1.setOnClickListener(this);
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()) {
case R.id.l_l: // if you touch on layout
// do your task
Toast.makeText(getApplicationContext(), "You Touch on: Linear_Layout",
Toast.LENGTH_LONG).show();
break;
case R.id.imageView1: // if you touch on Image
// do your task
Toast.makeText(getApplicationContext(), "You Touch on : Image ", Toast.LENGTH_LONG)
.show();
break;
default:
break;
}
}
}

How to place drag event on button in Android?

On my view I want to place a hidden button, and above this hidden button I want to place an image. Whenever the user drags on the image the button's drag event should be called. Can any one suggest how to do this? As there is no in-built method for drag events in Android.

use this code for drag
Main.java
package com.drag;
import android.app.Activity;
import android.os.Bundle;
public class Main extends Activity{
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// draw the view
setContentView(new DrawView(this));
}
}
DrawView.java
package com.drag;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Point;
import android.view.MotionEvent;
import android.view.View;
public class DrawView extends View
{
private ColorBall[] colorballs = new ColorBall[3]; // array that holds the balls
private int balID = 0; // variable to know what ball is being dragged
public DrawView(Context context) {
super(context);
setFocusable(true); //necessary for getting the touch events
// setting the start point for the balls
Point point1 = new Point();
point1.x = 50;
point1.y = 20;
Point point2 = new Point();
point2.x = 100;
point2.y = 20;
Point point3 = new Point();
point3.x = 150;
point3.y = 20;
// declare each ball with the ColorBall class
colorballs[0] = new ColorBall(context,R.drawable.bol_groen, point1);
colorballs[1] = new ColorBall(context,R.drawable.bol_rood, point2);
colorballs[2] = new ColorBall(context,R.drawable.bol_blauw, point3);
}
// the method that draws the balls
#Override protected void onDraw(Canvas canvas) {
//canvas.drawColor(0xFFCCCCCC); //if you want another background color
//draw the balls on the canvas
for (ColorBall ball : colorballs) {
canvas.drawBitmap(ball.getBitmap(), ball.getX(), ball.getY(), null);
}
}
// events when touching the screen
public boolean onTouchEvent(MotionEvent event) {
int eventaction = event.getAction();
int X = (int)event.getX();
int Y = (int)event.getY();
switch (eventaction ) {
case MotionEvent.ACTION_DOWN: // touch down so check if the finger is on a ball
balID = 0;
for (ColorBall ball : colorballs) {
// check if inside the bounds of the ball (circle)
// get the center for the ball
int centerX = ball.getX() + 25;
int centerY = ball.getY() + 25;
// calculate the radius from the touch to the center of the ball
double radCircle = Math.sqrt( (double) (((centerX-X)*(centerX-X)) + (centerY-Y)*(centerY-Y)));
// if the radius is smaller then 23 (radius of a ball is 22), then it must be on the ball
if (radCircle < 23){
balID = ball.getID();
break;
}
// check all the bounds of the ball (square)
//if (X > ball.getX() && X < ball.getX()+50 && Y > ball.getY() && Y < ball.getY()+50){
// balID = ball.getID();
// break;
//}
}
break;
case MotionEvent.ACTION_MOVE: // touch drag with the ball
// move the balls the same as the finger
if (balID > 0) {
colorballs[balID-1].setX(X-25);
colorballs[balID-1].setY(Y-25);
}
break;
case MotionEvent.ACTION_UP:
// touch drop - just do things here after dropping
break;
}
// redraw the canvas
invalidate();
return true;
}
}
ColorBall.java
package com.drag;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Point;
public class ColorBall
{
private Bitmap img; // the image of the ball
private int coordX = 0; // the x coordinate at the canvas
private int coordY = 0; // the y coordinate at the canvas
private int id; // gives every ball his own id, for now not necessary
private static int count = 1;
private boolean goRight = true;
private boolean goDown = true;
public ColorBall(Context context, int drawable) {
BitmapFactory.Options opts = new BitmapFactory.Options();
opts.inJustDecodeBounds = true;
img = BitmapFactory.decodeResource(context.getResources(), drawable);
id=count;
count++;
}
public ColorBall(Context context, int drawable, Point point) {
BitmapFactory.Options opts = new BitmapFactory.Options();
opts.inJustDecodeBounds = true;
img = BitmapFactory.decodeResource(context.getResources(), drawable);
id=count;
count++;
coordX= point.x;
coordY = point.y;
}
public static int getCount() {
return count;
}
void setX(int newValue) {
coordX = newValue;
}
public int getX() {
return coordX;
}
void setY(int newValue) {
coordY = newValue;
}
public int getY() {
return coordY;
}
public int getID() {
return id;
}
public Bitmap getBitmap() {
return img;
}
public void moveBall(int goX, int goY) {
// check the borders, and set the direction if a border has reached
if (coordX > 270){
goRight = false;
}
if (coordX < 0){
goRight = true;
}
if (coordY > 400){
goDown = false;
}
if (coordY < 0){
goDown = true;
}
// move the x and y
if (goRight){
coordX += goX;
}else
{
coordX -= goX;
}
if (goDown){
coordY += goY;
}else
{
coordY -= goY;
}
}
}