java– 更改颜色而不影响以前绘制的任何内容

概述我在我的应用程序中使用以下用于绘画的CustomView：packagecom.test.testing;importandroid.content.Context;importandroid.graphics.Canvas;importandroid.graphics.Color;importandroid.graphics.Paint;importandroid.graphics.Path;importandroid.graphics.Paint

我在我的应用程序中使用以下用于绘画的CustomVIEw：

package com.test.testing;import androID.content.Context;import androID.graphics.Canvas;import androID.graphics.color;import androID.graphics.Paint;import androID.graphics.Path;import androID.graphics.Paint.Style;import androID.vIEw.MotionEvent;import androID.Widget.TextVIEw;public class CustomVIEw extends TextVIEw {    Paint paint;    Path path;    float x = 0;    float y = 0;    private int cWhite = color.WHITE;    public CustomVIEw(Context context) {        super(context);        paint = new Paint();        path= new Path();        paint.setAlpha(255);        paint.setcolor(cWhite);        paint.setStyle(Style.stroke);        paint.setstrokeWIDth(20);    }    protected voID onDraw(Canvas canvas) {        super.onDraw(canvas);        canvas.drawPath(path,paint);        canvas.drawCircle(x, y, 10, paint);    }    public boolean ontouchEvent(MotionEvent event) {        int action = event.getAction();        switch (action) {        case MotionEvent.ACTION_DOWN:            path.moveto(event.getX(), event.getY());            path.lineto(event.getX(), event.getY());            break;        case MotionEvent.ACTION_MOVE:            x = event.getX();            y = event.getY();            path.lineto(x, y);            invalIDate();            break;        case MotionEvent.ACTION_UP:            path.lineto(event.getX(), event.getY());            break;        case MotionEvent.ACTION_CANCEL:            break;        default:            break;        }        return true;    }}

我设置了一个FrameLayout,它保留了用于绘制XML的画布：

<FrameLayout    androID:ID="@+ID/vIEwd"    androID:layout_wIDth="match_parent"    androID:layout_height="0dp"    androID:layout_weight="3"    androID:orIEntation="vertical" ></FrameLayout>

我在我的Activity中调用以获取视图以使用户能够绘制：

layout = (FrameLayout)findVIEwByID(R.ID.vIEwd);//layout.removeAllVIEws();vIEw = new CustomVIEw(Activity.this);vIEw.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));layout.addVIEw(vIEw);

我有不同的颜色选项,用户可以选择在我的Activity中的对话框中更改颜色描边颜色：

public voID colorHandle() {    // custom dialog    final Dialog dialog = new Dialog(this);    dialog.setContentVIEw(R.layout.colorlayout);    dialog.setTitle("Choose a Drawing color");    button btnWH = (button) dialog.findVIEwByID(R.ID.btnWhite);    button btnBL = (button) dialog.findVIEwByID(R.ID.btnBlack);    button btnBLU = (button) dialog.findVIEwByID(R.ID.btnBlue);    button btnCY = (button) dialog.findVIEwByID(R.ID.btnCyan);    button btnDG = (button) dialog.findVIEwByID(R.ID.btnDkGray);    button btnGR = (button) dialog.findVIEwByID(R.ID.btnGray);    button btnGRE = (button) dialog.findVIEwByID(R.ID.btnGreen);    button btnLG = (button) dialog.findVIEwByID(R.ID.btnLtGray);    button btnMG = (button) dialog.findVIEwByID(R.ID.btnmagenta);    button btnRD = (button) dialog.findVIEwByID(R.ID.btnRed);    button btnYE = (button) dialog.findVIEwByID(R.ID.btnYellow);    if (btnWH != null) {        btnWH.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.WHITE);                dialog.dismiss();            }        });    }    if (btnBL != null) {        btnBL.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.BLACK);                dialog.dismiss();            }        });    }    if (btnBLU != null) {        btnBLU.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.BLUE);                dialog.dismiss();            }        });    }    if (btnCY != null) {        btnCY.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.CYAN);                dialog.dismiss();            }        });    }    if (btnDG != null) {        btnDG.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.DKGRAY);                dialog.dismiss();            }        });    }    if (btnGR != null) {        btnGR.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.GRAY);                dialog.dismiss();            }        });    }    if (btnGRE != null) {        btnGRE.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.GREEN);                dialog.dismiss();            }        });    }    if (btnLG != null) {        btnLG.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.LTGRAY);                dialog.dismiss();            }        });    }    if (btnMG != null) {        btnMG.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.magenta);                dialog.dismiss();            }        });    }    if (btnRD != null) {        btnRD.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.RED);                dialog.dismiss();            }        });    }    if (btnYE != null) {        btnYE.setonClickListener(new VIEw.OnClickListener() {            public voID onClick(VIEw v) {                vIEw.paint.setcolor(color.YELLOW);                dialog.dismiss();            }        });    }    dialog.show();}

一切都很好,除非我每次选择一种新颜色,之前绘制的任何东西也会改变为新选择的颜色.无论接下来选择什么新颜色,我如何保持之前绘制的内容不变？

解决方法:

您将为每个touchEvent添加一个路径.然后使用Paint颜色的当前值绘制Path.这就是为什么你看到所有东西都用一种颜色绘制的原因.
您需要为每个颜色更改创建单独的路径和颜色,然后按顺序绘制它们,更改每个drawPath()调用的Paint的颜色

我不这么认为.突破路径并不是那么糟糕.

List<Pair<Path, Integer>> path_color_List = new ArrayList<Pair<Path,Integer>>()

然后每次你改变颜色.获取当前路径并查看.paint.getcolor并将其保存到列表中.

path_color_List.add( new Pair.create(path, vIEw.paint.getcolor());path = new Path();

然后在你的draw()中迭代path_color_List,每次都设置新的颜色

for (Pair<Path,Integer> path_clr : path_color_List ){   paint.setcolor(path_clr.second);  canvas.drawPath( path_clr.first, paint);}

接下来是你拥有的最后一个drawPath()

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