對不起,如果問題很傻,但我是Android新手。我在developer.android.сom上閱讀了很多,但不幸的是我找不到解決方案。 我在staсkoverflow上找到的大部分代碼完成了零件本身。 此視圖插入到FrameLayout中的活動中,放在文本上,並允許您在電子書中留下注釋。在Paint和Canvas上更改顏色Android
import java.util.ArrayList;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
public class PaintSurface extends View implements OnTouchListener {
private Canvas canvas;
private Path path;
private Paint paint;
private ArrayList<Path> paths = new ArrayList<Path>();
public PaintSurface(Context context) {
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
this.setOnTouchListener(this);
paint = new Paint();
paint.setAntiAlias(true);
paint.setDither(true);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.MITER);
paint.setStrokeCap(Paint.Cap.SQUARE);
paint.setColor(Color.RED);
paint.setStrokeWidth(16);
paint.setAlpha(100);
canvas = new Canvas();
path = new Path();
paths.add(path);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onDraw(Canvas canvas) {
for (Path p : paths) {
canvas.drawPath(p, paint);
}
}
private float mX, mY;
private static final float TOUCH_TOLERANCE = 4;
private void touch_start(float x, float y) {
path.reset();
path.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) {
path.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);
mX = x;
mY = y;
}
}
private void touch_up() {
path.lineTo(mX, mY);
canvas.drawPath(path, paint);
path = new Path();
paths.add(path);
}
@Override
public boolean onTouch(View arg0, 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;
}
public void setColor(int color) {
paint.setColor(color);
}
}
說明問題。 我畫了默認顏色的線,紅色。然後,使用setColor()更改爲綠色在紅線旁邊畫一條綠線。但第一條紅線也變綠了。如果更改樣式或筆觸寬度,則會發生此類更改。 如何繪製不同的顏色?
一種感覺,在幾個月內這個問題似乎我可笑和愚蠢,我自己會覺得自己很傻,我會感到羞恥,但現在我不知道如何解決這個問題?
我該如何使用它來解決我的問題? http://stackoverflow.com/questions/18521661/change-color-without-affecting-anything-previously-drawn – Si8