我想将自己的View转换为位图，但它不起作用
我的意思是在我看来画线
我的自定义视图代码：
public class PaintView extends View {
private Bitmap mBitmap;
private Canvas mCanvas;
private Path mPath;
private Paint mPaint;
private static final int TOUCH_TOLERANCE_DP = 24;
private static final int BACKGROUND = 0xFFDDDDDD;
private List<Point> mPoints = new ArrayList<Point>();
private int mLastPointIndex = 0;
private int mTouchTolerance;
private boolean isPathStarted = false;
private int x = 0;
public PaintView(Context context) {
super(context);
mCanvas = new Canvas();
mPath = new Path();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.BLACK);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(12);
mTouchTolerance = dp2px(TOUCH_TOLERANCE_DP);
// readSDFile("myTest.txt");
for (int i = 0; i < 500; i++) {
if (i < 250) {
Point p = new Point(i, i);
mPoints.add(p);
} else {
Point p = new Point(i, 500 - i);
mPoints.add(p);
}
}
}
public PaintView(Context context, AttributeSet attrs) {
super(context, attrs);
mCanvas = new Canvas();
mPath = new Path();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.BLACK);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(12);
mTouchTolerance = dp2px(TOUCH_TOLERANCE_DP);
readSDFile("myTest.txt");
// TODO just test points
// Point p1 = new Point(20, 20);
// Point p2 = new Point(100, 100);
// Point p3 = new Point(200, 250);
// Point p4 = new Point(280, 400);
// Point p5 = new Point(350, 600);
// Point p6 = new Point(400, 500);
// mPoints.add(p1);
// mPoints.add(p2);
// mPoints.add(p3);
// mPoints.add(p4);
// mPoints.add(p5);
// mPoints.add(p6);
}
public PaintView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
mCanvas = new Canvas();
mPath = new Path();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.BLACK);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(12);
mTouchTolerance = dp2px(TOUCH_TOLERANCE_DP);
}
@Override
protected void onSizeChanged(int width, int height, int oldWidth,
int oldHeight) {
super.onSizeChanged(width, height, oldWidth, oldHeight);
clear();
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(BACKGROUND);
canvas.drawBitmap(mBitmap, 0, 0, null);
canvas.drawPath(mPath, mPaint);
// // TODO remove if you dont want points to be drawn
for (Point point : mPoints) {
canvas.drawPoint(point.x, point.y, mPaint);
}
for (int i = 1; i < mPoints.size(); i++) {
mPath.moveTo(mPoints.get(i - 1).x, mPoints.get(i - 1).y);
mPath.quadTo(mPoints.get(i - 1).x, mPoints.get(i - 1).y,
mPoints.get(i).x, mPoints.get(i).y);
}
}
@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(x, y);
invalidate();
break;
}
return true;
}
private void touch_start(float x, float y) {
if (checkPoint(x, y, mLastPointIndex)) {
mPath.reset();
// user starts from given point so path can beis started
isPathStarted = true;
} else {
// user starts move from point which doen's belongs to mPinst list
isPathStarted = false;
}
}
// ADDED WITH LAST EDIT
private void touch_move(float x, float y) {
// draw line with finger move
if (isPathStarted) {
mPath.reset();
Point p = mPoints.get(mLastPointIndex);
mPath.moveTo(p.x, p.y);
mPath.lineTo(x, y);
}
}
/**
* Draws line.
*/
private void touch_up(float x, float y) {
mPath.reset();
if (checkPoint(x, y, mLastPointIndex + 1) && isPathStarted) {
// move finished at valid point so draw whole line
// start point
Point p = mPoints.get(mLastPointIndex);
mPath.moveTo(p.x, p.y);
// end point
p = mPoints.get(mLastPointIndex + 1);
mPath.lineTo(p.x, p.y);
mCanvas.drawPath(mPath, mPaint);
mPath.reset();
// increment point index
++mLastPointIndex;
isPathStarted = false;
}
}
/**
* Sets paint
*
* @param paint
*/
public void setPaint(Paint paint) {
this.mPaint = paint;
}
/**
* Returns image as bitmap
*
* @return
*/
public Bitmap getBitmap() {
return mBitmap;
}
/**
* Clears canvas
*/
public void clear() {
mBitmap = Bitmap.createBitmap(getWidth(), getHeight(),
Bitmap.Config.ARGB_8888);
mBitmap.eraseColor(BACKGROUND);
mCanvas.setBitmap(mBitmap);
invalidate();
}
/**
* Checks if user touch point with some tolerance
*/
private boolean checkPoint(float x, float y, int pointIndex) {
if (pointIndex == mPoints.size()) {
// out of bounds
return false;
}
Point point = mPoints.get(pointIndex);
// EDIT changed point.y to poin.x in the first if statement
if (x > (point.x - mTouchTolerance) && x < (point.x + mTouchTolerance)) {
if (y > (point.y - mTouchTolerance)
&& y < (point.y + mTouchTolerance)) {
return true;
}
}
return false;
}
public List<Point> getPoints() {
return mPoints;
}
public void setPoints(List<Point> points) {
this.mPoints = points;
}
private int dp2px(int dp) {
Resources r = getContext().getResources();
float px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp,
r.getDisplayMetrics());
return (int) px;
}}
我的主要课程代码： 我想在imageView中设置一个位图， 并显示它，但它不起作用我做错了什么？
public class LineTest extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
View myView = new PaintView(this);
setContentView(R.layout.display_bitmap);
ImageView imgView = (ImageView) findViewById(R.id.display_img);
Bitmap bitmap = getBitmapFromView(myView);
imgView.setImageBitmap(bitmap);
}
public static Bitmap getBitmapFromView(View view) {
// Define a bitmap with the same size as the view
Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(),
view.getHeight(), Bitmap.Config.ARGB_8888);
// Bind a canvas to it
Canvas canvas = new Canvas(returnedBitmap);
// Get the view's background
Drawable bgDrawable = view.getBackground();
if (bgDrawable != null)
// has background drawable, then draw it on the canvas
bgDrawable.draw(canvas);
else
// does not have background drawable, then draw white background on
// the canvas
canvas.drawColor(Color.WHITE);
// draw the view on the canvas
view.draw(canvas);
// return the bitmap
return returnedBitmap;
}