android– 向图形画布添加按钮

概述我正在使用这个问题的答案：DrawingonCanvasandsaveimage,以便创建一个画布来绘制图像.我正在打开一个名为DrawImage的FragmentActivity,当单击一个按钮时.在此活动中,我希望MyDrawView与浮动 *** 作按钮一起显示,允许用户在单击时保存其绘图.这就是我当前正在显示画布的方式,但

我正在使用这个问题的答案：Drawing on Canvas and save image,以便创建一个画布来绘制图像.

我正在打开一个名为DrawImage的FragmentActivity,当单击一个按钮时.在此活动中,我希望MyDrawVIEw与浮动 *** 作按钮一起显示,允许用户在单击时保存其绘图.

这就是我当前正在显示画布的方式,但是我不知道如何在它上面添加按钮.有任何想法吗？

的DrawImage

public class DrawImage extends FragmentActivity {@OverrIDeprotected voID onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        VIEw drawImageCanvas = new MyDrawVIEw(this.getApplicationContext());        setContentVIEw(drawImageCanvas);    }}

MyDrawVIEw(与链接相同)

public class MyDrawVIEw extends VIEw {private Bitmap  mBitmap;private Canvas  mCanvas;private Path    mPath;private Paint   mBitmapPaint;private Paint   mPaint;public MyDrawVIEw(Context c) {    super(c);    mPath = new Path();    mBitmapPaint = new Paint(Paint.DITHER_FLAG);    mPaint = new Paint();    mPaint.setAntiAlias(true);    mPaint.setDither(true);    mPaint.setcolor(0xFF000000);    mPaint.setStyle(Paint.Style.stroke);    mPaint.setstrokeJoin(Paint.Join.ROUND);    mPaint.setstrokeCap(Paint.Cap.ROUND);    mPaint.setstrokeWIDth(3);}@OverrIDeprotected voID onSizeChanged(int w, int h, int olDW, int oldh) {    super.onSizeChanged(w, h, olDW, oldh);    mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);    mCanvas = new Canvas(mBitmap);}@OverrIDeprotected voID onDraw(Canvas canvas) {    canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);    canvas.drawPath(mPath, mPaint);}private float mX, mY;private static final float touch_TolERANCE = 4;private voID touch_start(float x, float y) {    mPath.reset();    mPath.moveto(x, y);    mX = x;    mY = y;}private voID touch_move(float x, float y) {    float dx = Math.abs(x - mX);    float dy = Math.abs(y - mY);    if (dx >= touch_TolERANCE || dy >= touch_TolERANCE) {        mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);        mX = x;        mY =  y;    }}private voID touch_up() {    mPath.lineto(mX, mY);    // commit the path to our offscreen    mCanvas.drawPath(mPath, mPaint);    // kill this so we don't double draw    mPath.reset();}@OverrIDepublic boolean ontouchEvent(MotionEvent event) {    float x = event.getX();    float y = event.getY();    switch (event.getAction()) {        case MotionEvent.ACTION_DOWN:            touch_start(x, y);            invalIDate();            break;        case MotionEvent.ACTION_MOVE:            touch_move(x, y);            invalIDate();            break;        case MotionEvent.ACTION_UP:            touch_up();            invalIDate();            break;    }    return true;}public voID clear(){    mBitmap.erasecolor(color.transparent);    invalIDate();    System.gc();}}

解决方法:

您只将contentVIEw设置为MyDrawVIEw视图,因此布局中不再有任何视图(按钮).以这种方式添加按钮是不可能的.

解决方案是将MyDrawVIEw移动到xml文件(fragment_draw_image.xml)并设置内容v

<relativeLayout xmlns:androID="http://schemas.androID.com/apk/res/androID"    androID:layout_wIDth="match_parent"    androID:layout_height="match_parent">    <com.example.misah.test.MyDrawVIEw        androID:ID="@+ID/myVIEw"        androID:layout_wIDth="match_parent"        androID:layout_height="match_parent"/>    <button        androID:layout_wIDth="wrap_content"        androID:layout_height="wrap_content"        androID:text="Save Drawing"/></relativeLayout>

然后是setContentVIEw(R.layout.fragment_draw_image);在布局中,您可以在其上方绘制视图和按钮,以及您希望的任何其他内容.

编辑：

将此构造函数也添加到MyDrawVIEw中,您可以从xml中使用它：

public MyDrawVIEw(Context c) {    super(c);    init();}public MyDrawVIEw(Context context, @Nullable AttributeSet attrs) {    super(context, attrs);    init();}public MyDrawVIEw(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);    init();}public MyDrawVIEw(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {    super(context, attrs, defStyleAttr, defStyleRes);    init();}

并将构造函数中的所有doint添加到init方法(绘图等)

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