用AS在图片上进行涂鸦、清除并保存

引言

我们经常遇到需要在图片上进行编辑涂改的情况，电脑不能无时无刻带在我们身边，但是手机可以。

操作

在布局中设置两个部分，一个使用view存放需要涂改的图片，另一个用于安排清除涂鸦按钮和保存按钮。
图片部分：

com.example.myapplication2.HandWrite
        android:id="@+id/view"
        android:layout_width="match_parent"
        android:layout_height="300dp"
        android:gravity="center_horizontal"/>

两个按钮部分：

		<Button
            android:id="@+id/clear"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            android:text="清除涂鸦"
             />
        <Button
            android:id="@+id/download"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            android:text="保存"
            />

编写涂鸦的画笔，确定画线的起始坐标和终点坐标，画笔颜色和宽度

	Paint paint = null;             
    Bitmap originalBitmap = null;   
    Bitmap new1_Bitmap = null;      
    Bitmap new2_Bitmap = null;      
    float startX = 0,startY = 0;    
    float clickX = 0,clickY = 0;    
    boolean isMove = true;     
    boolean isClear = false;        
    int color = Color.BLUE;       
    float strokeWidth = 2f;

定义画笔操作和清除操作

public HandWrite(Context context, AttributeSet attrs)
    {
        super(context, attrs);
        originalBitmap = BitmapFactory
                .decodeResource(getResources(), R.drawable.dog)
                .copy(Bitmap.Config.ARGB_8888,true);
        new1_Bitmap = Bitmap.createBitmap(originalBitmap);
    }
    public void clear(){
        isClear = true;
        new2_Bitmap = Bitmap.createBitmap(originalBitmap);
        invalidate();
    }
    public void setStyle(float strokeWidth){
        this.strokeWidth = strokeWidth;
    }
    @Override
    protected void onDraw(Canvas canvas)
    {
        super.onDraw(canvas);
        canvas.drawBitmap(HandWriting(new1_Bitmap), 0, 0,null);
    }
    public Bitmap HandWriting(Bitmap o_Bitmap)
    {
        Canvas canvas = null;
        if(isClear) {
            canvas = new Canvas(new2_Bitmap);
        }
        else{
            canvas = new Canvas(o_Bitmap);
        }
        paint = new Paint();
        paint.setStyle(Paint.Style.STROKE);
        paint.setAntiAlias(true);
        paint.setColor(color);
        paint.setStrokeWidth(strokeWidth);
        if(isMove)
        {
            canvas.drawLine(startX, startY, clickX, clickY, paint);
        }
        startX = clickX;
        startY = clickY;
        if(isClear)
        {
            return new2_Bitmap;
        }
        return o_Bitmap;
    }
    @Override
    public boolean onTouchEvent(MotionEvent event)
    {
        clickX = event.getX();
        clickY = event.getY();
        if(event.getAction() == MotionEvent.ACTION_DOWN)
        {
            isMove = false;
            invalidate();
            return true;
        }
        else if(event.getAction() == MotionEvent.ACTION_MOVE)
        {
            isMove = true;
            invalidate();
            return true;
        }
        return super.onTouchEvent(event);
    }

对涂鸦后的图片进行保存。

@Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final Button btn = (Button) findViewById(R.id.download);
    }

 public boolean saveBmpToPath(final Bitmap bitmap, final String filePath) {
        if (bitmap == null || filePath == null) {
            return false;
        }
        boolean result = false; 
        File file = new File(filePath);
        OutputStream outputStream = null; 
        try {
            outputStream = new FileOutputStream(file);
            result = bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outputStream);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (outputStream != null) {
                try {
                    outputStream.close(); //关闭输出流
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return result;
    }

实现效果