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与浮动操作按钮一起显示,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 {
@Override
protected 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);
}
@Override
protected 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);
}
@Override
protected 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();
}
@Override
public 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();
}
原文地址:https://www.jb51.cc/android/1075126.html
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