I have the following code:
package com.teste;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.util.AttributeSet;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;
public class ball extends View implements View.OnTouchListener {
Bitmap littleBall;
float x, y;
private int mWidth, mHeight;
private GestureDetector mDetector;
public ball(Context context) {
super(context);
}
public ball(Context context, AttributeSet attrs) {
super(context, attrs);
}
#Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
mDetector = new GestureDetector(this.getContext(), new BallListener());
}
#Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
mWidth = View.MeasureSpec.getSize(widthMeasureSpec);
mHeight = View.MeasureSpec.getSize(heightMeasureSpec);
x = mWidth/2;
y = mHeight/2;
setMeasuredDimension(mWidth, mHeight);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
littleBall = BitmapFactory.decodeResource(getResources(), R.drawable.verde);
Bitmap resizedBitmap = Bitmap.createScaledBitmap(littleBall, 200, 200, false);
canvas.drawBitmap(resizedBitmap, (x - (resizedBitmap.getWidth() / 2)), (y - resizedBitmap.getHeight()/2), null);
}
#Override
public boolean onTouch(View v, MotionEvent event) {
Toast.makeText(getContext(), "teste", Toast.LENGTH_LONG);
return mDetector.onTouchEvent(event);
}
class BallListener extends GestureDetector.SimpleOnGestureListener {
#Override
public boolean onDown(MotionEvent e) {
return true;
}
#Override
public boolean onSingleTapUp(MotionEvent e) {
if (e.getAction() == MotionEvent.ACTION_UP) {
x = e.getX();
y = e.getY();
invalidate();
}
return super.onSingleTapUp(e);
}
}
}
In a near future i want make the ball moves to a place when i swipe my finger across the screen. But for the start, my goal is make the LittleBall (created using canvas and bitmap) change its position when i touch at the screen. I am using onTouch and a gestureListener. Searching on the net, i found others ways to get a touch like onTouchListener and even looking and Android Developer Help i did not understand what is the difference between those methods...
Can Someone explain in a easy way when i should use those methods and what im doing wrong to not even show my text?
Related
I am brand new to android and i was wondering if it was possible to add toast onFinishInflate. If this is a stupid question please excuse me.I have created a view like this.
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.view.View;
import android.widget.Toast;
public class CustomView extends View {
private Rect rectangle;
private Paint paint;
public CustomView(Context context) {
super(context);
int x = 50;
int y = 50;
int sideLength = 200;
// create a rectangle that we'll draw later
rectangle = new Rect(x, y, sideLength, sideLength);
// create the Paint and set its color
paint = new Paint();
paint.setColor(Color.GRAY);
}
#Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(Color.BLUE);
canvas.drawRect(rectangle, paint);
}
#Override
protected void onFinishInflate() {
super.onFinishInflate();
Toast.makeText(getApplicationContext(),"onfinishinflate",Toast.LENGTH_SHORT).show();
}
}
Update
View has it's own method called getContext(), so you can use like this
Toast.makeText(getContext(), "onfinishinflate", Toast.LENGTH_SHORT).show();
Reference
private Context context;
public CustomView(Context context) {
super(context);
this.context = context;
// Rest of ur codes
}
#Override
protected void onFinishInflate() {
super.onFinishInflate();
Toast.makeText(context, "onfinishinflate", Toast.LENGTH_SHORT).show();
}
set the context in your class using constructor, and use it for Toast purpose
I need to draw a point on ImageView Android.
I use custom subclass of View class and override onDraw method like:
public class DrawPoints extends View {
private float x;
private float y;
private Paint mPaint;
public DrawPoints(Context context, float x, float y) {
super(context);
this.x = x;
this.y = y;
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Log.i("TAG", "onDraw: " + x + "" + y);
mPaint = new Paint();
mPaint.setColor(Color.YELLOW);
canvas.drawCircle(x,y,200,mPaint);
}
}
In my MainActivity I use onTouch event to draw, also do not forget to invalidate(), but it does not draw a point.
public class MainActivity extends AppCompatActivity {
private ImageView mImageView;
private Canvas mCanvas;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mCanvas = new Canvas();
setContentView(R.layout.activity_main);
mImageView = (ImageView) findViewById(R.id.image_main);
mImageView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View view, MotionEvent motionEvent) {
float y = motionEvent.getY();
float x = motionEvent.getX();
new DrawPoints(MainActivity.this,x,y).draw(mCanvas);
mImageView.invalidate();
return false;
}
});
}
}
What could it be? I have already read many examples with onDraw on stackoverflow but none help.
You could just create an imageview that draw circle on touch events.
Example:
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import java.util.ArrayList;
public class DrawPoints extends android.support.v7.widget.AppCompatImageView {
private static final String TAG = DrawPoints.class.getSimpleName();
private ArrayList<Point> mSavedPoints = new ArrayList<>();
private Point mLastTouchPoint;
private Paint mPaint;
public DrawPoints(Context context) {
super(context);
init();
}
public DrawPoints(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public DrawPoints(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
mPaint = new Paint();
mPaint.setColor(Color.YELLOW);
}
#Override public boolean dispatchTouchEvent(MotionEvent event) {
mLastTouchPoint = new Point((int) event.getX(), (int) event.getY());
postInvalidate();
return super.dispatchTouchEvent(event);
}
#Override protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mLastTouchPoint != null) {
if (mLastTouchPoint.x > 0 || mLastTouchPoint.y > 0) {
mSavedPoints.add(mLastTouchPoint);
Log.i(TAG, mLastTouchPoint.toString());
}
}
for (Point point : mSavedPoints) {
canvas.drawCircle(point.x, point.y, 200, mPaint);
}
Log.i(TAG, mSavedPoints.toString());
}
}
I created a SurfaceView (you can see it in the following) and started in from my Main Activity. I overwrote the onTouchEvent method in the SurfaceView and the problem is that the data I want to have logged with Log.d isn't logged, I don't get any Message...
Does anyone have an idea how I can fix this?
My SurfaceView:
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
public class MainGamePanel extends SurfaceView implements SurfaceHolder.Callback {
private float top;
private float left;
private float bottom;
private float right;
private MainThread thread;
MainGamePanel(Context context) {
super(context);
getHolder().addCallback(this);
thread = new MainThread(getHolder(), this);
setFocusable(true);
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
setWillNotDraw(false);
thread.setRunningMode(MainThread.RUNNING);
thread.start();
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
while (retry) {
try {
thread.join();
retry = false;
} catch (Exception e) {
}
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
right = x + 30;
left = x - 30;
top = y - 30;
bottom = y + 30;
Log.d("tag", x + " " + y);
return true;
}
#Override
protected void onDraw(Canvas canvas) {
}
}
My Main Activity:
import android.app.Activity;
import android.os.Bundle;
import android.os.PersistableBundle;
public class MainActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState, PersistableBundle persistentState) {
super.onCreate(savedInstanceState, persistentState);
setContentView(new MainGamePanel(getApplicationContext()));
}
}
Try changing "getApplicationContext()" to "this" in following part of code:
setContentView(new MainGamePanel(getApplicationContext()));
to
setContentView(new MainGamePanel(this));
Iam beginner in android game development and i'm currently having some trouble on drawing pixels on the screen using bitmap and canvas.
Here is my code:
package com.example.arkanoid;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MotionEvent;
import android.widget.TextView;
import android.graphics.*;
public class MainActivity extends Activity {
Bitmap bitmap;
Canvas canvas;
int lastx=0, lasty=0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
bitmap = Bitmap.createBitmap(400,400,Bitmap.Config.ARGB_8888);
canvas = new Canvas(bitmap);
bitmap.prepareToDraw();
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public void drawPixel(int x, int y) {
if(bitmap.isMutable()) {
bitmap.setPixel(x,y,Color.rgb(100,100,100));
}
canvas.drawBitmap(bitmap,0,0,null);
}
public boolean onTouchEvent(MotionEvent event) {
int x = (int)event.getX();
int y = (int)event.getY();
TextView texto = (TextView)findViewById(R.id.textView1);
texto.setText("X: "+x+", Y: "+y);
if(lastx !=x || lasty !=y){
lastx=x;
lasty=y;
drawPixel(x,y);
}
return false;
}
}
When the function drawPixel(int x, int y) is called multiple times the application stops running:
And no pixels are drawn, so what is the error here? thanks for your time.
I forgot the LOG from LogCat, sorry:
http://txtup.co/eISoF
according for the logcat you uploaded, you need to check if x & y are between the bitmap size.
I am an amateur programmer, and have been playing around with android development. I am currently trying my hand at generating a fractal heightmap. In order to test if teh map is generating properly I need to be able to draw the map to the screen. This is where I've been running into trouble.
Here's the code for my MainActivity, DrawMap class (where my onDraw() is), and my CanvasThread() class.
Main Activity:
package com.psstudios.HMG;
import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
import android.view.View.OnClickListener;
import android.util.Log;
public class MainActivity extends Activity
{
/** Called when the activity is first created. */
Button Startgen = null;
Boolean run=true;
private void log(String text) {
Log.d("heightmap",text);
AppendLog app = new AppendLog(text);
}
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
Startgen = (Button) findViewById(R.id.startgen);
log("loop");
Startgen.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
log("Starting world generation");
WorldGen world=new WorldGen(200,200);
log("World generation complete, drawing heightmap");
setContentView(new DrawMap(MainActivity.this, world));
log("Went too far");
}
});
run=false;
}
}
DrawMap:
package com.psstudios.HMG;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Bitmap;
import android.graphics.Bitmap.*;
import android.graphics.Paint;
import android.graphics.Color;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.util.Log;
import android.util.*;
public class DrawMap extends SurfaceView implements SurfaceHolder.Callback
{
int drawtype=1; //variable for which type of map to draw
Bitmap drawbitmap=null;
CanvasThread canvasThread=null;
Boolean run= true;
int Worldx=200;
int Worldy=200;
WorldGen _world=null;
public void log(String text){
Log.d("Heightmap", text);
AppendLog app = new AppendLog(text);
}
public void init(){
log("init();");
canvasThread=new CanvasThread(getHolder(), this);
setFocusable(true);
log("Post-CanvasThread");
}
public DrawMap(Context context){
super(context);
log("DrawMap(Context context)");
getHolder().addCallback(this);
init();
}
public DrawMap(Context context, AttributeSet attrs) {
super(context, attrs);
log("DrawMap(Context context, AttributeSet attrs)");
getHolder().addCallback(this);
init();
}
public DrawMap(Context context,WorldGen world){
super(context);
log("DrawMap(Context context, WorldGen world)");
getHolder().addCallback(this);
_world=world;
init();
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format,int width, int height){
log("surfaceChanged()");
}
#Override
public void surfaceCreated(SurfaceHolder holder){
log("Surface Created");
canvasThread.setRunning(true);
canvasThread.run();
}
#Override
public void surfaceDestroyed(SurfaceHolder holder){
log("Surface Destroyed");
Boolean retry = true;
canvasThread.setRunning(false);
while(retry){
try {
canvasThread.join();
retry=false;
} catch (InterruptedException e) {
//we will try again and again
}
}
}
#Override
public void onDraw(Canvas canvas){
log("onDraw()");
Paint paint = new Paint();
Paint paint2 = new Paint();
//canvas.drawColor(Color.BLACK);
paint.setColor(Color.WHITE);
paint.setStrokeWidth(10);
paint2.setColor(Color.BLUE);
for(int x=0; x<Worldx-1; x++){
for(int y=0; y<Worldy-1; y++){
//log(x + " : " + y);
canvas.drawPoint(x+20, y+20, paint);
canvas.drawPoint(x+220, y+220, paint2);
}
}
}
}
CanvasThread:
package com.psstudios.HMG;
import android.graphics.Canvas;
import android.view.*;
import android.util.Log;
public class CanvasThread extends Thread
{
private SurfaceHolder _surfaceHolder;
private DrawMap _drawMap;
private Boolean _run = false;
private void log(String text){
Log.d("HeightmapGen",text);
AppendLog app = new AppendLog(text);
}
public CanvasThread(SurfaceHolder surfaceHolder, DrawMap drawMap){
_surfaceHolder=surfaceHolder;
_drawMap=drawMap;
log("CanvasThread()");
}
public void setRunning(Boolean run){
log("setRunning()");
_run=run;
}
#Override
public void run() {
log("run()");
Canvas c;
while(_run){
c=null;
try{
c=_surfaceHolder.lockCanvas(null);
synchronized (_surfaceHolder) {
_drawMap.onDraw(c);
}
} finally {
if(c != null){
_surfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
}
The program makes it to the onDraw(); function, and runs through the for loop, but nothing is showing up on the screen. I imagine I'm missing something pretty stupid, but I cannot seem to figure out what's wrong.
Thanks in advance for any help you guys can give me.