我正在使用此应用在Android中绘制免费线
DrawerView.java
public class DrawerView extends View {
public static Paint paint;
Paint paint2 = new Paint();
public Path path = new Path();
public Path circlePath = new Path();
public static int lineCol = Color.BLUE;
public static boolean isTouchable = false;
public LayoutParams params;
public DrawerView(Context context, AttributeSet attrs){
super(context, attrs);
paint = new Paint();
paint.setAntiAlias(true);
paint.setColor(lineCol);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(4f);
}
public void onButtonPress(){
// resets the screen
path.reset();
// Calls the onDraw() method
postInvalidate();
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawPath(path, paint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (!isTouchable){
return false;
} else {
// Gives you x and y coordinates on the Event.
float pointX = event.getX();
float pointY = event.getY();
// Checks for the event that occurs
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
path.moveTo(pointX, pointY);
return true;
case MotionEvent.ACTION_MOVE:
path.lineTo(pointX, pointY);
circlePath.reset();
circlePath.addCircle(pointX, pointY, 30, Path.Direction.CW);
break;
case MotionEvent.ACTION_UP:
circlePath.reset();
break;
default:
return false;
}
postInvalidate();
return true;
}
}
}
DrawLines.java
public class DrawLines extends Activity {
DrawerView myView;
public Button btnReset;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.draw_line);
myView = (DrawerView)findViewById(R.id.custView);
btnReset = (Button) findViewById(R.id.button1);
btnReset.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
// resets the screen
myView.path.reset();
// Calls the onDraw() method
myView.postInvalidate();
}
});
}
}
draw_line.xml
<Button
android:id="@+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Clear" />
<com.example.drawline.DrawerView
android:id="@+id/custView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@+id/button1"
android:layout_margin="5dp"
custom:lineColor="#ff0099" />
它适合我，但我想能够选择线的颜色，所以我在draw_line.xml中添加了一个按钮，当按下它时会显示一个对话框，要求用户选择颜色。这是对话框的代码
public void openSelectColorDialog()
{
final Dialog d = new Dialog(this);
d.setTitle("Select Color");
d.setContentView(R.layout.military_list);
int image[] = { R.drawable.black, R.drawable.blue, R.drawable.yellow};
ArrayList<HashMap<String, String>> objArayList = new ArrayList<HashMap<String, String>>();
for (int i = 0; i < image.length; i++) {
HashMap<String, String> listData = new HashMap<String, String>();
listData.put("image", Integer.toString(image[i]));
objArayList.add(listData);
}
String[] from = { "image"};
int[] to = { R.id.list_image };
SimpleAdapter listAdapter = new SimpleAdapter(this, objArayList,
R.layout.military_list_item, from, to);
ListView lst1 = (ListView) d.findViewById(android.R.id.list);
lst1.setAdapter(listAdapter);
lst1.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parentView, View childView, int position, long id) {
if (position == 0) {
// the code of color line
d.dismiss();
} else if (position == 1) {
// the code of blue line
d.dismiss();
} else {
// the code of yellow line
d.dismiss();
}
myView.postInvalidate();
}
});
d.show();
}
为了使颜色像我选择的那样，我必须添加什么代码？
考虑我是否写了这段代码 DrawerView.paint.setColor（Color.BLACK）; 整条线将其颜色更改为所选颜色，这不是我想要的。 我希望新线的颜色与我选择的一样，并保持旧线的颜色。
希望有人得到我的意思。
提前致谢。
修改
新代码是： ColoredPath.java
public class ColoredPath {
private Paint paint;
private Path path = new Path();
private int color;
public ColoredPath() {
paint = new Paint();
color = Color.BLACK;
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(4f);
paint.setAntiAlias(true);
paint.setColor(color);
}
public ColoredPath(int color) {
paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(4f);
paint.setAntiAlias(true);
paint.setColor(color);
}
public void setColor(int color){
this.color = color;
}
public int getColor(){
return color;
}
public void setPaint(Paint paint){
this.paint = paint;
}
public Paint getPaint() {
return paint;
}
public void setPath(Path path){
this.path = path;
}
public Path getPath() {
return path;
}
}
DrawerView.java
public class DrawerView extends View {
public Path circlePath = new Path();
public static int LINE_COLOR = 0;
public static boolean isTouchable = false;
public List<ColoredPath> paths = new ArrayList<ColoredPath>();
public ColoredPath currentPath;
public DrawerView(Context context, AttributeSet attrs){
super(context, attrs);
currentPath = new ColoredPath();
paths.add(currentPath);
}
public void newLine(int color){
System.out.println("in newLine method");
currentPath = new ColoredPath(color);
paths.add(currentPath);
//postInvalidate();
}
public void onButtonPress(){
// resets the screen
currentPath.getPath().reset();
// Calls the onDraw() method
postInvalidate();
}
@Override
protected void onDraw(Canvas canvas) {
System.out.println("size of paths: "+paths.size());
canvas.drawPath(currentPath.getPath(), currentPath.getPaint());
for(int i = 0; i < paths.size(); ++i) {
//ColoredPath coloredPath = paths.get(i);
canvas.drawPath(currentPath.getPath(), currentPath.getPaint());
}
}
public Path getLastPath() {
Path path = new Path();
for(int i = 0; i < paths.size(); ++i) {
path.addPath(paths.get(i).getPath());
}
return path;
}
@Override
public boolean onTouchEvent(MotionEvent event) {
if (!isTouchable){
return false;
} else {
// Gives you x and y coordinates on the Event.
float pointX = event.getX();
float pointY = event.getY();
// Checks for the event that occurs
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
currentPath.getPath().moveTo(pointX, pointY);
//getLastPath().moveTo(pointX, pointY);
return true;
case MotionEvent.ACTION_MOVE:
currentPath.getPath().lineTo(pointX, pointY);
//getLastPath().lineTo(pointX, pointY);
circlePath.reset();
circlePath.addCircle(pointX, pointY, 30, Path.Direction.CW);
break;
case MotionEvent.ACTION_UP:
circlePath.reset();
break;
default:
return false;
}
postInvalidate();
return true;
}
}
}
和MainActivity.java
if (position == 1) {
// blue
myView.newLine(Color.BLUE);
d.dismiss();
}
这很好用并为线条着色但是当我选择任何颜色时它会导致删除最后一行，我希望所有的线条都有颜色。
答案 0 :(得分：1)
因为Path本身不包含任何有关它的颜色的信息（颜色由Canvas管理）我建议你为每个具有不同颜色的新路径创建一对（Path，Paint），并在onTouch中仅使用当前对事件。所以这里有一些代码说明了这个想法
public class ColoredPath {
private Paint paint;
private Path path;
public ColoredPath(Paint paint, Path path) {
this.paint = paint;
this.path = path;
}
public Paint getPaint() {
return paint;
}
public Path getPath() {
return path;
}
}
private List<ColoredPath> paths = new ArrayList<ColoredPath>();
public DrawerView(Context context, AttributeSet attrs){
super(context, attrs);
//custom paint can be used here
paths.add(new ColoredPath(new Paint(), new Path()));
}
/////
@Override
protected void onDraw(Canvas canvas) {
for(ColoredPath coloredPath : paths) {
canvas.drawPath(coloredPath.getPath(), coloredPath.getPaint());
}
}
路径为List<ColoredPath>。此外，您还需要ColoredPath currentPath等字段。