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我有以下的，我在我的應用程序中使用繪畫CustomView什麼：改變顏色，而不會影響之前繪製的
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;
}
}
我設置一個FrameLayout這使畫布在我的XML繪圖：
<FrameLayout
android:id="@+id/viewd"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="3"
android:orientation="vertical" >
</FrameLayout>
我打電話給我的Activity內獲得視圖以使用戶能夠借鑑：
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);
我有不同的顏色選項，用戶可以從中選擇改變我的Activity內的Dialog繪畫描邊顏色：
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();
}
一切工作正常，除了每次我選擇了新的顏色，任何事情以前也畫更改爲新選擇的顏色。無論接下來選擇何種新顏色，我如何保留以前不變的任何東西？
在onDraw函數中，您可以嘗試設置canvas = new Canvas（）; – jaesanx
沒有工作。它甚至不啓動Draw方法。 – Si8
您正在更改顏色，但重新繪製所有內容。你需要做的是分別存儲已經繪製的內容。然後每次都將其複製，並在頂部添加。 – Doomsknight