Java 保存新图像时,会保留旧画布
我有一个画布,允许用户绘制和保存。它还允许用户更改颜色,并使用不同的颜色在同一画布上绘制 我的绘画课:Java 保存新图像时,会保留旧画布,java,android,android-canvas,Java,Android,Android Canvas,我有一个画布,允许用户绘制和保存。它还允许用户更改颜色,并使用不同的颜色在同一画布上绘制 我的绘画课: 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.
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.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;
import com.test.testing.*;
public class CustomView extends View {
Paint paint;
Path path;
float x = 0;
float y = 0;
private int cWhite = Color.WHITE;
private Button btnS, btnSa;
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);
btnS = (Button)((FreeDraw) context).findViewById(R.id.shareButton);
btnSa = (Button)((FreeDraw) context).findViewById(R.id.saveButton);
}
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());
if (btnS.getVisibility() == View.VISIBLE && btnS != null) {
//if share button is displaying but I drew something else
//the share button should disappear and I should be presented
//with the save button
btnS.setVisibility(View.GONE);
btnSa.setVisibility(View.VISIBLE);
}
if (btnSa.getVisibility() == View.VISIBLE && btnS != null) {
//do nothing...
}
invalidate();
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());
invalidate();
break;
case MotionEvent.ACTION_CANCEL:
break;
default:
break;
}
return true;
}
}
在我的活动中,我调用Paint类并使用如下XML布局:
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
同样在同一活动中,我有以下处理颜色变化的代码:
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) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.WHITE);
dialog.dismiss();
}
});
}
if (btnBL != null) {
btnBL.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.BLACK);
dialog.dismiss();
}
});
}
if (btnBLU != null) {
btnBLU.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.BLUE);
dialog.dismiss();
}
});
}
if (btnCY != null) {
btnCY.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.CYAN);
dialog.dismiss();
}
});
}
if (btnDG != null) {
btnDG.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.DKGRAY);
dialog.dismiss();
}
});
}
if (btnGR != null) {
btnGR.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.GRAY);
dialog.dismiss();
}
});
}
if (btnGRE != null) {
btnGRE.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.GREEN);
dialog.dismiss();
}
});
}
if (btnLG != null) {
btnLG.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.LTGRAY);
dialog.dismiss();
}
});
}
if (btnMG != null) {
btnMG.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.MAGENTA);
dialog.dismiss();
}
});
}
if (btnRD != null) {
btnRD.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.RED);
dialog.dismiss();
}
});
}
if (btnYE != null) {
btnYE.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
view.paint.setColor(Color.YELLOW);
dialog.dismiss();
}
});
}
dialog.show();
}
我必须为每种颜色重复以下代码,因为一旦我绘制了某个东西并更改了颜色并绘制了其他东西,以前绘制的所有路径都将更改为新颜色,此代码将其修复:
layout = (FrameLayout)findViewById(R.id.viewd);
//layout.removeAllViews();
view = new CustomView(FreeDraw.this);
view.setLayoutParams(new FrameLayout.LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT));
layout.addView(view);
“活动”中代码的“保存图像”部分为:
View.OnClickListener saveHandle = new View.OnClickListener() {
public void onClick(View v) {
new SaveImageTask().execute(null, null, null);
}
};
public class SaveImageTask extends AsyncTask<Void, Void, Void> {
@Override
protected Void doInBackground(Void... params) { //Running in background
View content = layout;
content.setDrawingCacheEnabled(true);
content.setDrawingCacheQuality(View.DRAWING_CACHE_QUALITY_HIGH);
Bitmap bitmap = content.getDrawingCache();
File folder = new File(Environment.getExternalStorageDirectory() + "/PB");
if (!folder.exists()) {
folder.mkdir();
}
file = new File(folder + "/pb_image_" + Math.random() + ".png");
FileOutputStream ostream;
try {
file.createNewFile();
ostream = new FileOutputStream(file);
bitmap.compress(CompressFormat.PNG, 100, ostream);
ostream.flush();
ostream.close();
isSaved = true;
} catch (Exception e) {
e.printStackTrace();
isSaved = false;
}
return null;
}
@Override
protected void onPreExecute() { //Activity is on progress
//displayToast("Your image is saving...");
btnSave.setVisibility(View.GONE);
btnShare.setVisibility(View.GONE);
pb.setVisibility(View.VISIBLE);
}
@Override
protected void onPostExecute(Void v) { //Activity is done...
if (isSaved == true) {
displayToast("Image was saved.");
btnSave.setVisibility(View.GONE);
btnShare.setVisibility(View.VISIBLE);
pb.setVisibility(View.GONE);
}
if (isSaved == false) {
displayToast("Unable to save image. Try again later.");
btnSave.setVisibility(View.VISIBLE);
btnShare.setVisibility(View.GONE);
pb.setVisibility(View.GONE);
}
}
}
我希望做的是:
当我画一些东西并保存图像时,共享按钮应该出现,画布不应该清除
当“共享”按钮可见时,我在画布上绘制了其他内容,“保存”按钮应重新出现
当我再次按下SAVE按钮时,它应该会保存新的画布图形,但不工作,它正在保存我在第一步中保存的先前绘制的画布
如何修改代码以执行此操作:
不要为每种颜色创建新画布,而是创建新路径。
保存画布上的图形后,我在现有画布上绘制新内容并保存。新画布应与所有旧的和新绘制的路径一起保存
如果按下擦除按钮,则清除整个画布
不要为每种颜色创建新画布,而是创建新路径
每次用户触摸画布并理论上绘制一些东西时,为其创建路径。存储新路径及其颜色,并在onDraw方法中迭代路径结构,并使用保存的颜色绘制每个路径:
// this will hold the data of each path the user draws
class DrawnItem {
int color = Color.GREEN; // default values
Path line = new Path();
}
Paint paint;
int mCurrentColor = Color.GREEN; // start with green
ArrayList<DrawnItem> mDrawings = new ArrayList<DrawnItem>();
// in the onDraw method:
protected void onDraw(Canvas canvas) {
final int count = mDrawings.size();
for (int i = 0; i < count; i++) {
final DrawnItem item = mDrawings.get(i);
paint.setColor(item.color);
canvas.drawPath(item.line, paint);
}
paint.setColor(mCurrentColor);
canvas.drawCircle(x, y, 10, paint);
}
private DrawnItem mCurrentItem = null;
// and in the onTouch method:
public boolean onTouchEvent(MotionEvent event) {
final int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
// the user started a new drawing so build a new DrawnItem
mCurrentItem = new DrawnItem();
mCurrentitem.color= mCurrentColor;
mDrawings.add(mCurrentItem);
// use the item.line to setup the Path with the x and y values
// ....
invalidate();
break;
case MotionEvent.ACTION_MOVE:
x = event.getX();
y = event.getY();
mCurrentItem.line.lineTo(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP:
mCurrentItem.line.lineTo(event.getX(), event.getY());
mCurrentItem = null;
invalidate();
break;
case MotionEvent.ACTION_CANCEL:
mCurrentItem = null; // this drawing session was canceled so this DrawnItem is now closed
break;
default:
break;
如果按下擦除按钮,则清除整个画布
清除以前的路径结构并在自定义视图上调用invalidate:
mDrawings.clear();
customView.invalidate();
不要为每种颜色创建新画布,而是创建新路径
每次用户触摸画布并理论上绘制一些东西时,为其创建路径。存储新路径及其颜色,并在onDraw方法中迭代路径结构,并使用保存的颜色绘制每个路径:
// this will hold the data of each path the user draws
class DrawnItem {
int color = Color.GREEN; // default values
Path line = new Path();
}
Paint paint;
int mCurrentColor = Color.GREEN; // start with green
ArrayList<DrawnItem> mDrawings = new ArrayList<DrawnItem>();
// in the onDraw method:
protected void onDraw(Canvas canvas) {
final int count = mDrawings.size();
for (int i = 0; i < count; i++) {
final DrawnItem item = mDrawings.get(i);
paint.setColor(item.color);
canvas.drawPath(item.line, paint);
}
paint.setColor(mCurrentColor);
canvas.drawCircle(x, y, 10, paint);
}
private DrawnItem mCurrentItem = null;
// and in the onTouch method:
public boolean onTouchEvent(MotionEvent event) {
final int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
// the user started a new drawing so build a new DrawnItem
mCurrentItem = new DrawnItem();
mCurrentitem.color= mCurrentColor;
mDrawings.add(mCurrentItem);
// use the item.line to setup the Path with the x and y values
// ....
invalidate();
break;
case MotionEvent.ACTION_MOVE:
x = event.getX();
y = event.getY();
mCurrentItem.line.lineTo(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP:
mCurrentItem.line.lineTo(event.getX(), event.getY());
mCurrentItem = null;
invalidate();
break;
case MotionEvent.ACTION_CANCEL:
mCurrentItem = null; // this drawing session was canceled so this DrawnItem is now closed
break;
default:
break;
如果按下擦除按钮,则清除整个画布
清除以前的路径结构并在自定义视图上调用invalidate:
mDrawings.clear();
customView.invalidate();
我不能在Paint类中使用私有变量,因为我将从另一个类访问这些变量。正在初始化的变量密钥在哪里?@ZahidH private关键字不起作用,如果需要可以删除它。关于输入错误的关键变量,它是前一行的颜色//使用下面的路径。我的代码里的其他东西都应该是对的吗?@ZahidH我不知道我应该看到什么?!您应该尝试并测试代码,然后提及出现的任何问题。@ZahidH如果您想要绘制路径的确切顺序,则需要一种新的方法。我对我的答案做了一些修改。我不理解save的问题。我不能在我的Paint类中使用私有变量,因为我将从另一个类访问这些变量。正在初始化的变量密钥在哪里?@ZahidH private关键字不起作用,如果需要可以删除它。关于输入错误的关键变量,它是前一行的颜色//使用下面的路径。我的代码里的其他东西都应该是对的吗?@ZahidH我不知道我应该看到什么?!您应该尝试并测试代码,然后提及出现的任何问题。@ZahidH如果您想要绘制路径的确切顺序,则需要一种新的方法。我对我的答案做了一些修改。我不明白储蓄的问题。