我的代码：
根据Graham的评论进行编辑
PaintView.java
public class PaintView extends View {
private Bitmap mBitmap;
private Canvas mCanvas;
private Path mPath;
private Paint mPaint;
private static final int TOUCH_TOLERANCE_DP = 20;
private static final int BACKGROUND = 0xFFDDDDDD;
private List<Point> mPoints = new ArrayList<Point>();
private int mLastPointIndex = 0;
private int marks = 0;
private int mTouchTolerance;
private boolean isPathStarted = false;
@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);
}
}
@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);
if (checkPoint(x, y, mLastPointIndex + 1)) {
p = mPoints.get(mLastPointIndex + 1);
mPath.lineTo(p.x, p.y);
mCanvas.drawPath(mPath, mPaint);
mPath.reset();
++mLastPointIndex;
marks++;
update();
} else {
mPath.lineTo(x, y);
}
}
}
private void update() {
// TODO Auto-generated method stub
String newMarks = "";
newMarks = Integer.toString(marks);
Log.e("Marks", ":" + newMarks);
}
/**
* Draws line.
*/
private void touch_up(float x, float y) {
mPath.reset();
marks--;
update();
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;
}
}
}
MainActivity.java
public class MainActivity extends Activity {
TextView textView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView)findViewById(R.id.marks_id);
//update();
}
/*private void update() {
// TODO Auto-generated method stub
String newMarks = "";
newMarks = Integer.toString(marks);
TextView textView = (TextView)findViewById(R.id.marks_id);
textView.setText(newMarks);
}*/
}
我想从PaintView.java获取标记的值，并将该值分配给MainActivity.java中的textView。这是一个noob问题，但请帮助我。
答案 0 :(得分：2)
您可以使用观察者模式执行此操作，
<强> ObserverActivity.java
这是你的观察者，有不止一个观察者
public class ObserverActivity extends Activity implements Observer{
com.talha.examples.PaintView paint1;
private ActivityHolder paintHolder = ActivityHolder.getInstance();
EditText editText1;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_paintview);
paint1= (com.talha.examples.PaintView)findViewById(R.id.paint1);
editText1= (EditText)findViewById(R.id.editText1);
paintHolder.registerObserver(this);
}
@Override
public void updateNewValue(String str) {
editText1.setText(str);
}
}
<强> Observer.java 你的所有观察者都必须实现这个
public interface Observer {
public void updateNewValue(String str);
}
Subject.java
public interface Subject {
public void registerObserver(Observer o);
public void removeObserver(Observer o);
public void notifyObserver();
}
ActivityHolder.java
此类将使用单例将观察者保存在列表中，然后您可以调用所有观察者来通知数据已更改
import java.util.ArrayList;
public class ActivityHolder implements Subject {
private static ActivityHolder uniqueActivityHolder;
private ArrayList observers;
private String newValue;
private ActivityHolder() {
observers = new ArrayList();
}
public static synchronized ActivityHolder getInstance() {
if (uniqueActivityHolder == null) {
uniqueActivityHolder = new ActivityHolder();
}
return uniqueActivityHolder;
}
public void registerObserver(Observer o) {
observers.add(o);
}
public void removeObserver(Observer o) {
int i = observers.indexOf(o);
if (i >= 0) {
observers.remove(i);
}
}
public void notifyObserver() {
for (int i = 0; i < observers.size(); i++) {
Observer observer = (Observer) observers.get(i);
observer.updateNewValue(newValue);
}
}
public void valueChanged() {
notifyObserver();
}
public void setNewValue(String _NewValue) {
this.newValue = _NewValue;
valueChanged();
}
}
<强> PaintView.java
绘制视图数据获取包含观察者列表的ActivityHolder唯一实例，然后它将通知代码下面的所有观察者
for（int i = 0; i＆lt; observers.size（）; i ++）{ Observer observer =（Observer）observers.get（i）; observer.updateNewValue（NEWVALUE）; }
import java.util.ArrayList;
import java.util.List;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.View;
public class PaintView extends View{
private Bitmap mBitmap;
private Canvas mCanvas;
private Path mPath;
private Paint mPaint;
private static final int TOUCH_TOLERANCE_DP = 20;
private static final int BACKGROUND = 0xFFDDDDDD;
private List<Point> mPoints = new ArrayList<Point>();
private int mLastPointIndex = 0;
private int marks = 0;
private int mTouchTolerance;
private boolean isPathStarted = false;
private ActivityHolder paintHolder = ActivityHolder.getInstance();
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);
// TODO just test points
Point p1 = new Point(133, 123);
Point p2 = new Point(149, 136);
Point p3 = new Point(182, 137);
Point p4 = new Point(206, 118);
Point p5 = new Point(208, 87);
Point p6 = new Point(187, 71);
Point p7 = new Point(144, 78);
Point p8 = new Point(124, 101);
Point p9 = new Point(113, 128);
Point p10 = new Point(112, 157);
Point p11 = new Point(119, 188);
Point p12 = new Point(134, 209);
Point p13 = new Point(162, 228);
Point p14 = new Point(194, 238);
Point p15 = new Point(232, 240);
Point p16 = new Point(263, 237);
Point p17 = new Point(289, 224);
Point p18 = new Point(315, 204);
Point p19 = new Point(332, 174);
Point p20 = new Point(339, 128);
Point p21 = new Point(329, 95);
Point p22 = new Point(304, 73);
Point p23 = new Point(280, 69);
Point p24 = new Point(254, 87);
Point p25 = new Point(248, 116);
Point p26 = new Point(259, 143);
Point p27 = new Point(278, 153);
Point p28 = new Point(241, 157);
Point p29 = new Point(192, 160);
Point p30 = new Point(150, 159);
mPoints.add(p1);
mPoints.add(p2);
mPoints.add(p3);
mPoints.add(p4);
mPoints.add(p5);
mPoints.add(p6);
mPoints.add(p7);
mPoints.add(p8);
mPoints.add(p9);
mPoints.add(p10);
mPoints.add(p11);
mPoints.add(p12);
mPoints.add(p13);
mPoints.add(p14);
mPoints.add(p15);
mPoints.add(p16);
mPoints.add(p17);
mPoints.add(p18);
mPoints.add(p19);
mPoints.add(p20);
mPoints.add(p21);
mPoints.add(p22);
mPoints.add(p23);
mPoints.add(p24);
mPoints.add(p25);
mPoints.add(p26);
mPoints.add(p27);
mPoints.add(p28);
mPoints.add(p29);
mPoints.add(p30);
}
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);
// TODO just test points
Point p1 = new Point(133, 123);
Point p2 = new Point(149, 136);
Point p3 = new Point(182, 137);
Point p4 = new Point(206, 118);
Point p5 = new Point(208, 87);
Point p6 = new Point(187, 71);
Point p7 = new Point(144, 78);
Point p8 = new Point(124, 101);
Point p9 = new Point(113, 128);
Point p10 = new Point(112, 157);
Point p11 = new Point(119, 188);
Point p12 = new Point(134, 209);
Point p13 = new Point(162, 228);
Point p14 = new Point(194, 238);
Point p15 = new Point(232, 240);
Point p16 = new Point(263, 237);
Point p17 = new Point(289, 224);
Point p18 = new Point(315, 204);
Point p19 = new Point(332, 174);
Point p20 = new Point(339, 128);
Point p21 = new Point(329, 95);
Point p22 = new Point(304, 73);
Point p23 = new Point(280, 69);
Point p24 = new Point(254, 87);
Point p25 = new Point(248, 116);
Point p26 = new Point(259, 143);
Point p27 = new Point(278, 153);
Point p28 = new Point(241, 157);
Point p29 = new Point(192, 160);
Point p30 = new Point(150, 159);
mPoints.add(p1);
mPoints.add(p2);
mPoints.add(p3);
mPoints.add(p4);
mPoints.add(p5);
mPoints.add(p6);
mPoints.add(p7);
mPoints.add(p8);
mPoints.add(p9);
mPoints.add(p10);
mPoints.add(p11);
mPoints.add(p12);
mPoints.add(p13);
mPoints.add(p14);
mPoints.add(p15);
mPoints.add(p16);
mPoints.add(p17);
mPoints.add(p18);
mPoints.add(p19);
mPoints.add(p20);
mPoints.add(p21);
mPoints.add(p22);
mPoints.add(p23);
mPoints.add(p24);
mPoints.add(p25);
mPoints.add(p26);
mPoints.add(p27);
mPoints.add(p28);
mPoints.add(p29);
mPoints.add(p30);
}
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);
}
protected void onSizeChanged(int width, int height, int oldWidth,
int oldHeight) {
super.onSizeChanged(width, height, oldWidth, oldHeight);
clear();
}
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);
}
}
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);
if (checkPoint(x, y, mLastPointIndex + 1)) {
p = mPoints.get(mLastPointIndex + 1);
mPath.lineTo(p.x, p.y);
mCanvas.drawPath(mPath, mPaint);
mPath.reset();
++mLastPointIndex;
marks++;
update();
} else {
mPath.lineTo(x, y);
}
}
}
private void update() {
// TODO Auto-generated method stub
String newMarks = "";
newMarks = Integer.toString(marks);
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// when you set the new value all your observers will be notified
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
paintHolder.setNewValue(newMarks);
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
// !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Log.e("Marks", ":" + newMarks);
}
/**
* Draws line.
*/
private void touch_up(float x, float y) {
mPath.reset();
marks--;
update();
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);
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;
}
}