Aggiungi immagini su tela con Android

Question

Sono nuovo ad Android Java e non so davvero come far apparire il pulsante sul mio VISTO dopo un lungo periodo di ricerche online. Riesco a vedere il mio pulsante nel layout ma non nella visualizzazione quando eseguo il debug. Non sono sicuro di inserire più immagini dopo aver fatto clic sul pulsante. Se correggo il codice, correggimi. Qualsiasi aiuto sarà molto apprezzato. Grazie!

mio codice in quanto segue:

package com.example.oncanvas; 

import android.app.Activity; 

public class Main extends Activity { 

    @Override 
     public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     DrawView DrawView = new DrawView(this); 
     DrawView.setBackgroundColor(Color.WHITE); 
     setContentView(DrawView); 
     DrawView.requestFocus(); 

} 

    public class DrawView extends View { 

     private Bitmap mBitmap; 
     private Canvas mCanvas; 
     private Path mPath; 
     private Paint mBitmapPaint; 
     private Paint mPaint; 

     public DrawView(Context c) { 
      super(c); 

      mPath = new Path(); 
      mBitmapPaint = new Paint(Paint.DITHER_FLAG); 


      mPaint = new Paint(); 
      mPaint.setAntiAlias(true); 
      mPaint.setDither(true); 
      mPaint.setColor(0xFF000000); 
      mPaint.setStyle(Paint.Style.STROKE); 
      mPaint.setStrokeJoin(Paint.Join.ROUND); 
      mPaint.setStrokeCap(Paint.Cap.ROUND); 
       mPaint.setStrokeWidth(3); 
     } 

    protected void onSizeChanged(int w, int h, int oldw, int oldh) { 
     super.onSizeChanged(w, h, oldw, oldh); 
     mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888); 
     mCanvas = new Canvas(mBitmap); 
    } 

    @Override 
    protected void onDraw(Canvas canvas) { 
     canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint); 

     canvas.drawPath(mPath, mPaint); 
    } 

    private float mX, mY; 
    private static final float TOUCH_TOLERANCE = 4; 

    private void touch_start(float x, float y) { 
     mPath.reset(); 
     mPath.moveTo(x, y); 
     mX = x; 
     mY = y; 
    } 
    private void touch_move(float x, float y) { 
     float dx = Math.abs(x - mX); 
     float dy = Math.abs(y - mY); 
     if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) { 
      mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2); 
      mX = x; 
      mY = y; 
     } 
    } 
    private void touch_up() { 
     mPath.lineTo(mX, mY); 
     // commit the path to our offscreen 
     mCanvas.drawPath(mPath, mPaint); 
     // kill this so we don't double draw 
     mPath.reset(); 
    } 

    @Override 
    public boolean onTouchEvent(MotionEvent event) { 
     float x = event.getX(); 
     float y = event.getY(); 

     switch (event.getAction()) { 
      case MotionEvent.ACTION_DOWN: 
       touch_start(x, y); 
       invalidate(); 
       break; 
      case MotionEvent.ACTION_MOVE: 
       touch_move(x, y); 
       invalidate(); 
       break; 
      case MotionEvent.ACTION_UP: 
       touch_up(); 
       invalidate(); 
       break; 
     } 
     return true; 
    } 

    public void clear(){ 
     mBitmap.eraseColor(Color.TRANSPARENT); 
     invalidate(); 
     System.gc(); 
    }} 

}

Si tratta di XML per il layout

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:id="@+id/linearLayout" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:background="@drawable/ic_launcher" 
    > 

<Button 
    android:text="Button" 
    android:id="@+id/button1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content"> 

</Button> 

<com.example.oncanvas 
    android:id="@+id/drawView1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content">   

     </com.example.oncanvas> 
</LinearLayout> 

Answer 1

Il suo solo un clue..Add il codice

@Override 
    public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when) { 
     super.draw(canvas, mapView, shadow);     

     // convert point to pixels 
     Point screenPts = new Point(); 
     mapView.getProjection().toPixels(pointToDraw, screenPts); 

     // add marker 
     Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.marker); 
     canvas.drawBitmap(bmp, screenPts.x, screenPts.y - 24, null); // 24 is the height of image  
     return true; 
    } 
} 

Answer 2

Dentro OnDraw() se è necessario disegnare mutti immagini che dovresti chiamare: canvas.drawBitmap() tempi di muting con valori di margine diversi.

for(int i=0;i<4;i++){ 
    canvas.drawBitmap(bmp, (i*5), (i*10), null) 
}