用户如何在触摸时也能画出线条跟随手指？Android 开发

Posted 2023-02-26

【中文标题】用户如何在触摸时也能画出线条跟随手指？Android 开发

【英文标题】：How can the user also draw on touch so the line follow his finger?Android development

【发布时间】：2013-04-03 16:18:19

【问题描述】：

我有这个代码来为教练制作一个篮球板，用户可以在其中移动球员并改变背景球场。 现在用户可以画出跟随他手指的线条。我怎样才能做到这一点？ 我搜索它，我发现我必须创建一个 View 类，但我无法连接。也许有人我要写什么代码？

public class HalfCourt extends Activity
/** Called when the activity is first created. */
ImageView img, img2, img3, img4, img5, img6, img7, img8, img9, img10 =null;
AbsoluteLayout aLayout;
public LayoutParams params, params2,params3,params4, params5, params6, parmas7, params8, params9, params10;
int status=0;
public Item red_out;
public Button lock,reset, erase;
MyTouchListener touchlistener;



@Override
public void onCreate(Bundle savedInstanceState) 
    super.onCreate(savedInstanceState);
    setContentView(R.layout.halfcourt);

    //View custom = (View)findViewById(R.id.view1);





    aLayout= (AbsoluteLayout)findViewById(R.id.absLayout);

    img=(ImageView)findViewById(R.id.imageView);
    img2=(ImageView)findViewById(R.id.imageView22);
    img3=(ImageView)findViewById(R.id.imageView3);
    img4=(ImageView)findViewById(R.id.imageView4);
    img5=(ImageView)findViewById(R.id.imageView5);
    img6=(ImageView)findViewById(R.id.imageView6);
    img7=(ImageView)findViewById(R.id.imageView7);
    img8=(ImageView)findViewById(R.id.imageView8);
    img9=(ImageView)findViewById(R.id.imageView9);
    img10=(ImageView)findViewById(R.id.imageView10);



    lock = (Button)findViewById(R.id.lock_button);
    reset = (Button)findViewById(R.id.reset_button);
    erase = (Button)findViewById(R.id.erase_button);

    /* 
     * 
     * Αρχικοποίηση των TouchListeners
     *  
     * */
    img.setOnTouchListener(new OnTouchListener() 

            @Override
            public boolean onTouch(View v, MotionEvent event) 

                status=1;

                return false;
            
    );

    img2.setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 

            status=2;

            return false;
        
    );

    img3.setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 

            status=3;

            return false;
        
    );

    img4.setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 

            status=4;

            return false;
        
    );

    img5.setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 

            status=5;

            return false;
        
    );

    img6.setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 

            status=6;

            return false;
        
    );

    img7.setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 

            status=7;

            return false;
        
    );

    img8.setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 

            status=8;

            return false;
        
    );

    img9.setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 

            status=9;

            return false;
        
    );

    img10.setOnTouchListener(new OnTouchListener() 

        @Override
        public boolean onTouch(View v, MotionEvent event) 

            status=10;

            return false;
        
    );


    touchlistener = new MyTouchListener();
    aLayout.setOnTouchListener(touchlistener);

    LockXandO locking = new LockXandO();
    lock.setOnClickListener(locking);
    lock.setText("Lock");

    ResetPositions reseting = new ResetPositions();
    reset.setOnClickListener(reseting);


    

public boolean onCreateOptionsMenu(Menu menu)

        super.onCreateOptionsMenu(menu);
        MenuInflater mitsos = getMenuInflater();
        mitsos.inflate(R.menu.half_court_menu, menu);
        return true;    
    

public boolean onOptionsItemSelected(MenuItem item)
        switch(item.getItemId())
        case R.id.red_out:
            if (item.getTitle()== "Αφαίρεσε τους κόκκινους")
                item.setTitle("Πρόσθεσε τους κόκκινους");
            
            else
                item.setTitle("Αφαίρεσε τους κόκκινους");
            
            return true;
        case R.id.change_to_full_court:
            startActivity(new Intent("com.mitsos.thebasic.TUTORIAL3"));
            return true;
    

    return false;


public class LockXandO implements OnClickListener
    /**
     * Η μέθοδος όπου κλειδώνω και ξεκλειδώνω τους "Παίκτες"
     */

    @Override
    public void onClick(View v) 
        /**
         *  Εδώ διαλέγουμε αν είμαστε σε κατάσταση κλειδώματος ή ξεκλειδώματος 
        **/
        if (lock.getText() == "Lock")
            kleidwse();
            lock.setText("Unlock");
        
        else 
            ksekleidwse();
            lock.setText("Lock");
        
    

    private void kleidwse() 
        /* 
         *    Με αυτή τη μέθοδο κλειδώνουν οι "Παίκτες" 
         */
        aLayout.setOnTouchListener(null);

    

    public void ksekleidwse()
        /**  
         *    Με αυτή τη μέθοδο ξεκλειδώνουν οι "Παίκτες" 
         **/
        aLayout.setOnTouchListener(touchlistener);
    




public class ResetPositions implements OnClickListener

    @Override
    public void onClick(View v) 
        ResetMe();
        ksekleidwse();
        lock.setText("Lock");

    

    private void ksekleidwse()
        /**  
         *    Την ξαναχρησιμοποιώ εδώ για να ξεκλειδώσουν οι παίχτες καθώς επανέρχονται στις αρχικές θέσεις 
         **/
        aLayout.setOnTouchListener(touchlistener);
    

    @SuppressWarnings("deprecation")
    private void ResetMe()

        aLayout.setOnTouchListener(touchlistener);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,105,250);
        img.setLayoutParams(params);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,165,250);
        img2.setLayoutParams(params);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,225,250);
        img3.setLayoutParams(params);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,285,250);
        img4.setLayoutParams(params);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,345,250);
        img5.setLayoutParams(params);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,105,330);
        img6.setLayoutParams(params);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,165,330);
        img7.setLayoutParams(params);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,225,330);
        img8.setLayoutParams(params);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,285,330);
        img9.setLayoutParams(params);
        params = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,345,330);
        img10.setLayoutParams(params);

        aLayout.setOnTouchListener(touchlistener);
    



public class MyTouchListener implements OnTouchListener

    @SuppressWarnings("deprecation")
    @Override
    public boolean onTouch(View v, MotionEvent event) 
        /*
         * 
         * Επιλογή της εικόνας που θα κινηθεί με το status
         * 
         */
        if(status==1) 
        
        LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                (int)event.getX()-img.getWidth()/2,(int)event.getY()-img.getHeight()/2);
        img.setLayoutParams(lp);
        
        else if (status ==2)
        
            LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                    (int)event.getX()-img2.getWidth()/2,(int)event.getY()-img2.getHeight()/2);
            img2.setLayoutParams(lp);
        
        else if (status ==3)
        
            LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                    (int)event.getX()-img3.getWidth()/2,(int)event.getY()-img3.getHeight()/2);
            img3.setLayoutParams(lp);
        
        else if (status ==4)
        
            LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                    (int)event.getX()-img4.getWidth()/2,(int)event.getY()-img4.getHeight()/2);
            img4.setLayoutParams(lp);
        
        else if (status ==5)
        
            LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                    (int)event.getX()-img2.getWidth()/2,(int)event.getY()-img2.getHeight()/2);
            img5.setLayoutParams(lp);
        
        else if (status ==6)
        
            LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                    (int)event.getX()-img6.getWidth()/2,(int)event.getY()-img6.getHeight()/2);
            img6.setLayoutParams(lp);
        
        else if (status ==7)
        
            LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                    (int)event.getX()-img7.getWidth()/2,(int)event.getY()-img7.getHeight()/2);
            img7.setLayoutParams(lp);
        
        else if (status ==8)
        
            LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                    (int)event.getX()-img8.getWidth()/2,(int)event.getY()-img8.getHeight()/2);
            img8.setLayoutParams(lp);
        
        else if (status ==9)
        
            LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                    (int)event.getX()-img9.getWidth()/2,(int)event.getY()-img9.getHeight()/2);
            img9.setLayoutParams(lp);
        
        else if (status ==10)
        
            LayoutParams lp = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,
                    (int)event.getX()-img10.getWidth()/2,(int)event.getY()-img10.getHeight()/2);
            img10.setLayoutParams(lp);
        
        if(event.getAction()==MotionEvent.ACTION_UP)
        status=0;

        

        return true;    

    



public class FingerDrawingView extends View

  private static final boolean DEBUG = false;
  private static final float MAXP = 0.75F;
  private static final float MINP = 0.25F;
  private static final String TAG = "FingerDrawingView";
  private static final float TOUCH_TOLERANCE = 4.0F;
  private Bitmap mBackupBitmap;
  private Bitmap mBitmap;
  private Paint mBitmapPaint;
  private Canvas mCanvas;
  private boolean mDrawingEnable = false;
  private MaskFilter mEmboss;
  private int mHeight;
  private Paint mPaint = new Paint();
  private Path mPath;
  private int mWidth;
  private float mX;
  private float mY;

  public FingerDrawingView(Context paramContext)
  
    super(paramContext);
    this.mPaint.setAntiAlias(true);
    this.mPaint.setDither(true);
    this.mPaint.setColor(-1);
    this.mPaint.setStyle(Paint.Style.STROKE);
    this.mPaint.setStrokeJoin(Paint.Join.ROUND);
    this.mPaint.setStrokeCap(Paint.Cap.ROUND);
    this.mPaint.setStrokeWidth(5.0F);
  

  private void touch_move(float paramFloat1, float paramFloat2)
  
    float f1 = Math.abs(paramFloat1 - this.mX);
    float f2 = Math.abs(paramFloat2 - this.mY);
    if ((f1 >= 4.0F) || (f2 >= 4.0F))
    
      this.mPath.quadTo(this.mX, this.mY, (paramFloat1 + this.mX) / 2.0F, (paramFloat2 + this.mY) / 2.0F);
      this.mX = paramFloat1;
      this.mY = paramFloat2;
    
  

  private void touch_start(float paramFloat1, float paramFloat2)
  
    this.mPath.reset();
    this.mPath.moveTo(paramFloat1, paramFloat2);
    this.mX = paramFloat1;
    this.mY = paramFloat2;
  

  private void touch_up()
  
    this.mPath.lineTo(this.mX, this.mY);
    this.mCanvas.drawPath(this.mPath, this.mPaint);
    this.mPath.reset();
  

  public void backupCanvas()
  
    this.mBackupBitmap = Bitmap.createBitmap(this.mBitmap);
  



  public boolean getDrawingEnable()
  
    return this.mDrawingEnable;
  

  public void initCanvas(int paramInt1, int paramInt2)
  
    this.mWidth = paramInt1;
    this.mHeight = paramInt2;
    this.mBitmap = Bitmap.createBitmap(paramInt1, paramInt2, Bitmap.Config.ARGB_8888);
    this.mCanvas = new Canvas(this.mBitmap);
    this.mPath = new Path();
    this.mBitmapPaint = new Paint(4);
    this.mBitmapPaint.setAlpha(16777215);
  

  public boolean loadCanvas(String paramString)
  
    Bitmap localBitmap = BitmapFactory.decodeFile(paramString);
    if (localBitmap != null)
    
      this.mBitmap = localBitmap.copy(Bitmap.Config.ARGB_8888, true);
      this.mCanvas.setBitmap(this.mBitmap);
      invalidate();
      return true;
    
    return false;
  

  protected void onDraw(Canvas paramCanvas)
  
    if ((this.mBitmap != null) && (this.mPath != null))
    
      paramCanvas.drawBitmap(this.mBitmap, 0.0F, 0.0F, this.mBitmapPaint);
      paramCanvas.drawPath(this.mPath, this.mPaint);
    
  

  protected void onSizeChanged(int paramInt1, int paramInt2, int paramInt3, int paramInt4)
  
    super.onSizeChanged(paramInt1, paramInt2, paramInt3, paramInt4);
  

【问题讨论】：

请格式化您的代码。

【参考方案1】：

Donn Felker 有一些示例代码（取自 Square），可以在图像上平滑绘制。见the sample code in Donn's repository

【讨论】：

对不起我的烂摊子！我想做这样的白色线条：play.google.com/store/apps/… 我该怎么做？