单击按钮时如何保存画布绘图并显示它

Question

嘿，我正在尝试创建 android 应用程序，我可以在底部使用两个按钮在画布上绘图 我设法让绘图工作但是现在我需要添加两个按钮（一个用于将绘图画布保存到数据库（如果可能的话是 Sqlite）或位图，另一个用于从 sqlite 导入图像并将其显示到图形视图）

现在我不知道我必须在其中输入什么代码才能使保存和显示按钮正常工作，所以请帮助我编写代码并感谢您的时间:)

这是我目前的代码（图形绘制工作正常，现在我需要保存和显示按钮的代码，以及我在 graphicsview.java 和 MainActivity.java 中遗漏的代码）

GraphicsView.java

package org.example.graphics;

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.graphics.RectF;
import android.graphics.Path.Direction;
import android.view.*;

public class GraphicsView extends View implements View.OnTouchListener {

public GraphicsView(Context context) {
    super(context);
    setBackgroundColor(Color.WHITE);
    setOnTouchListener(this);
}

ArrayList<MyPoint> arrOfPoints=new ArrayList<MyPoint>();

class MyPoint
{
    float x, y;
}
float downx, downy;

@Override
protected void onDraw(Canvas canvas) {
    // Drawing commands go here

    Paint rectPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    rectPaint.setStyle(Paint.Style.FILL_AND_STROKE);
    rectPaint.setColor(Color.BLACK);
    canvas.drawRoundRect(new RectF(0, 0, 100, 100), 10, 10, rectPaint);

    rectPaint.setColor(Color.BLUE);
    rectPaint.setAlpha(40);
    canvas.drawCircle(300, 300, 200, rectPaint);
    canvas.drawRect(new RectF(40, 40, 200, 200), rectPaint);
    Paint textPaint = new Paint(Paint.ANTI_ALIAS_FLAG
            | Paint.STRIKE_THRU_TEXT_FLAG);
    canvas.drawText("Hello there!", 200, 200, textPaint);

    canvas.drawText("You clicked on " + downx + "," + downy, 200, 600,
            textPaint);
        for(int i=0;i<arrOfPoints.size();i++)
                {
                    canvas.drawCircle(arrOfPoints.get(i).x, arrOfPoints.get(i).y, 20, rectPaint);
                }

}

@Override
public boolean onTouch(View arg0, MotionEvent arg1) {
    int action = arg1.getAction();
    MyPoint p=null;
    switch (action) {
    case MotionEvent.ACTION_DOWN:
        downx = arg1.getX();
        downy = arg1.getY();

        p=new MyPoint();
        p.x=arg1.getX();p.y=arg1.getY();

        arrOfPoints.add(p);
        invalidate();
        break;
    case MotionEvent.ACTION_MOVE:
        downx = arg1.getX();
        downy = arg1.getY();
        p=new MyPoint();
        p.x=arg1.getX();p.y=arg1.getY();
        arrOfPoints.add(p);
        invalidate();
        break;
    case MotionEvent.ACTION_UP:

        break;
    case MotionEvent.ACTION_CANCEL:
        break;
    default:
        break;
    }
    return true;
}

MainActivity.java

package org.example.graphics;
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Path.Direction;
import android.graphics.RectF;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(new GraphicsView(this));
}

ma​​in.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="vertical"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent"
 android:background="@drawable/background">

 <org.example.graphics.GraphicsView
   android:id="@+id/graphics"
   android:layout_width="fill_parent"
   android:layout_height="341dp" />

   <Button
    android:id="@+id/ChoosePictureButton"/>
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Choose Picture"

 <Button
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="Save Picture" android:id="@+id/SavePictureButton"/>

</LinearLayout>

我的 AndroidManifest.xml 仍处于默认状态，因为我还没有编辑其中的任何内容

Answer 1

您可以在保存按钮单击侦听器中使用此代码。

int canvasWidth = 500;
int canvasHeight = 500;
View v = new GraphicsView(MainActivity.this);
Bitmap bitmap = Bitmap.createBitmap(canvasWidth, canvasHeight, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
v.draw(canvas);

//now bitmap has your canvas image

//set it to your ImageView
yourImageView.setImageBitmap(bitmap);

//or save to sdcard
File dir = new File("/sdcard/yourAppFolder/");
if (!dir.isDirectory()) {
    dir.mkdirs();
}
File outputFile = new File(dir, "image.jpg");
OutputStream fout = null;
fout = new FileOutputStream(outputFile);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fout);
fout.flush();
fout.close();