2

每次单击撤消和重做时都会出错，我不知道为什么会出现此错误

java.lang.IllegalStateException: Could not execute method of the activity.

谁能帮我解决这个问题。提前致谢。下面是我的代码及其错误日志

--绘图类

public class Draw extends Activity implements {

public static String filex;

private static final int SELECT_PICTURE = 1;

public static String selectedImagePath;
public static Bitmap cBitmap;

public static Integer resize;
public static Integer imageBackgroundEraser;
// Instance variables

public static Paint       mPaint;
private MaskFilter  mEmboss;
private MaskFilter  mBlur;
private MyView      mView;
private int mImageCount = 0;
private int mLastBg = 0;

public static Integer WW;
public static Integer WH;

private float BrushWidth; 
private int  thickness;
private int BrushColor;
public static int backgroundColor; 
float Mx1,My1;
float x,y;

@SuppressWarnings("deprecation")
@Override

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_draw);

    Display display = getWindowManager().getDefaultDisplay(); //***


    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_draw4_fun_main);

    Display display = getWindowManager().getDefaultDisplay(); //***

    WH = display.getHeight();  //***
    WW = display.getWidth();  //***

    final MyView myView = new MyView(this);
    frm_layout=(FrameLayout) findViewById(R.id.main_frame);
    frm_layout.addView(myView);


    setInitialPaint();
    backgroundColor = Color.WHITE;

}

private void setInitialPaint() {
    //bgColor = 0xFFFFFFFF; // default bg color white
    BrushWidth = 3;
    BrushColor = 0xFF000000; //**
    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setDither(true);
    mPaint.setColor(BrushColor);
    mPaint.setStyle(Paint.Style.STROKE);
    mPaint.setStrokeJoin(Paint.Join.ROUND);
    mPaint.setStrokeCap(Paint.Cap.ROUND);
    mPaint.setStrokeWidth(BrushWidth);
    mPaint.setPathEffect(new CornerPathEffect(30) );
    //mEmboss = new EmbossMaskFilter(new float[] { 1, 1, 1 },0.4f, 6, 3.5f);

    //mBlur = new BlurMaskFilter(8, BlurMaskFilter.Blur.NORMAL);
}

public void onClick(View view){
    switch (view.getId()){
    case R.id.undoBtn:  
        mView.onClickUndo();
    break;

    case R.id.redoBtn:
        mView.onClickRedo();
    break;

    case R.id.saveBtn:
        File myDir=new File("/sdcard/Pictures/Draw");
        myDir.mkdirs();
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date(System.currentTimeMillis())); //***
        String fname = timeStamp + ".png";
        File file = new File (myDir, fname);
        System.out.println(file+"----> file");
        if (file.exists ()) file.delete ();
        saveAsPng(file);
    break;


    }
}

public void saveAsPng (File f)
{
    String fname = f.getAbsolutePath ();

    FileOutputStream fos = null;
    try {
        fos = new FileOutputStream (f);
        mView.mBitmap.compress (CompressFormat.PNG, 100, fos);  
        sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri.parse("file://"+ Environment.getExternalStorageDirectory())));
        Toast.makeText (getApplicationContext(), "Saved " + fname, Toast.LENGTH_LONG).show ();
    } catch (Throwable ex) {
      Toast.makeText (getApplicationContext(), "Error: " + ex.getMessage (), Toast.LENGTH_LONG).show ();
      ex.printStackTrace ();
    }

} // end saveAsPng

} // end Main

---MyView类

public class MyView extends View {

/**
 */
// Constants and variables
    private static final float MINP = 0.25f;
    private static final float MAXP = 0.75f;

    public static Bitmap  mBitmap;
    private Canvas  mCanvas;
    private Path    mPath;
    private Paint   mBitmapPaint;
    private ArrayList<Path> paths = new ArrayList<Path>();
    private ArrayList<Path> undonePaths = new ArrayList<Path>(); 

   // public int backgroundColor;

/**
 */

    public MyView(Context c) 
    {
        super(c);
        /*if (Draw.selectedImagePath == null) {*/
        setFocusable(true);
        setFocusableInTouchMode(true);      
            // Figure out how this works. Seems odd that we set up a canvas and a bitmap. 
            // I don't see how it connects to what shows on screen.    
            mBitmap = Bitmap.createBitmap(Draw4FunMain.WW, Draw4FunMain.WH, Bitmap.Config.ARGB_8888);
            mCanvas = new Canvas(mBitmap);
            mPath = new Path();
            mBitmapPaint = new Paint(Paint.DITHER_FLAG);
            // mCanvas.setBackgroundResource(0xFFFFFFFF);
            if (Draw.imageBackgroundEraser == null) {
                mCanvas.drawColor (Color.WHITE);
            } else {
                mCanvas.drawColor (Color.TRANSPARENT); 
            }
             mCanvas.drawColor(Color.TRANSPARENT);
    }

    public MyView (Context c, int color)
    {
        super(c);
        setFocusable(true);
        setFocusableInTouchMode(true);      
            mBitmap = Bitmap.createBitmap(Draw.WW, Draw.WH, Bitmap.Config.ARGB_8888);
            mCanvas = new Canvas(mBitmap);
            mPath = new Path();
            mBitmapPaint = new Paint(Paint.DITHER_FLAG);
            mCanvas.drawColor (color);

    }

/**
 */
// Methods

/**
 */
@Override protected void onSizeChanged(int w, int h, int oldw, int oldh) 
{
    super.onSizeChanged(w, h, oldw, oldh);
}

/**
 */
@Override protected void onDraw(Canvas canvas) 
{

         // canvas.drawColor(Color.TRANSPARENT);

          canvas.drawBitmap(mBitmap, 0, 0, null);

          for (Path p : paths){
              canvas.drawPath(p, Draw.mPaint);
              //System.out.println("p-->" + p);
             // System.out.println("Draw.mPaint-->" + Draw4FunMain.mPaint);
          }
          canvas.drawPath(mPath, Draw.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, Draw.mPaint);
        // kill this so we don't double draw
        mPath.reset();

        paths.add(mPath);
        mPath = new Path();
        System.out.println("path-->" + paths);  
        System.out.println("size-->" + paths.size());
    }

/**
 */
    public void onClickUndo () { 
        if (paths.size()>0) 
        { 
           undonePaths.add(paths.remove(paths.size()-1));
           invalidate();
         }
        else
        {

        }
         //toast the user 
    }

    public void onClickRedo (){
        if (undonePaths.size()>0) 
       { 
           paths.add(undonePaths.remove(undonePaths.size()-1)); 
           invalidate();
       } 
       else 
       {

       }
    }

@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;
    }

} // end MyView

错误 - - - 

11-14 14:55:39.022: E/AndroidRuntime(1728): FATAL EXCEPTION: main
11-14 14:55:39.022: E/AndroidRuntime(1728): java.lang.IllegalStateException: Could not execute method of the activity
11-14 14:55:39.022: E/AndroidRuntime(1728):     at android.view.View$1.onClick(View.java:3591)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at android.view.View.performClick(View.java:4084)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at android.view.View$PerformClick.run(View.java:16966)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at android.os.Handler.handleCallback(Handler.java:615)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at android.os.Handler.dispatchMessage(Handler.java:92)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at android.os.Looper.loop(Looper.java:137)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at android.app.ActivityThread.main(ActivityThread.java:4899)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at java.lang.reflect.Method.invokeNative(Native Method)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at java.lang.reflect.Method.invoke(Method.java:511)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:558)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at dalvik.system.NativeStart.main(Native Method)
11-14 14:55:39.022: E/AndroidRuntime(1728): Caused by: java.lang.reflect.InvocationTargetException
11-14 14:55:39.022: E/AndroidRuntime(1728):     at java.lang.reflect.Method.invokeNative(Native Method)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at java.lang.reflect.Method.invoke(Method.java:511)
11-14 14:55:39.022: E/AndroidRuntime(1728):     at android.view.View$1.onClick(View.java:3586)
11-14 14:55:39.022: E/AndroidRuntime(1728):     ... 11 more
11-14 14:55:39.022: E/AndroidRuntime(1728): Caused by: java.lang.NullPointerException
11-14 14:55:39.022: E/AndroidRuntime(1728):     at com.draw.Draw4FunMain.onClick(Draw.java:246)
11-14 14:55:39.022: E/AndroidRuntime(1728):     ... 14 more
4

2 回答 2

3

您的 logCat 在代码的第 246 行指出了 NullPointerException。我将假设这是这些行：

public void onClick(View view){
    switch (view.getId()){
    case R.id.undoBtn:  
        mView.onClickUndo();
    break;

    case R.id.redoBtn:
        mView.onClickRedo();
    break;

问题是，你没有初始化mView. 在 中onCreate，您改为初始化一个局部变量myView。将该实例分配给mView应该可以解决您的问题。

于 2012-11-14T07:35:25.610 回答
1

是的。我也认为 Paul-Jan 是正确的。以下行

final MyView myView = new MyView(this);

在 Draw.java 中的 onCreate 方法应该被纠正。

myView = new MyView(this);
于 2012-11-14T07:48:59.940 回答