我正在尝试构建绘图应用程序。首先，我试图在屏幕上绘制一些东西，这是可行的。现在，我想绕圈绕我的手指。无法运行该应用程序，并且在编译时没有错误或警告。有什么问题，我该如何解决？
我认为onTouchEvent永远不会调用。
我的视图类：
package gorrebeeck.david.dgor.eazydraw;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.drawable.ShapeDrawable;
import android.graphics.drawable.shapes.OvalShape;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;
public class CustomDrawableView extends View {
private ShapeDrawable mDrawable;
int x = 10;
int y = 10;
@Override
public boolean onTouchEvent(MotionEvent e) {
this.x=(int)e.getX();
this.y=(int)e.getY();
this.invalidate();
return true;
}
public CustomDrawableView(Context context) {
super(context);
int width = 50;
int height = 50;
mDrawable = new ShapeDrawable(new OvalShape());
mDrawable.getPaint().setColor(0xff74AC23);
mDrawable.setBounds(x, y, x + width, y + height);
}
protected void onDraw(Canvas canvas) {
mDrawable.draw(canvas);
}
}
多数民众赞成在加载的类：
package gorrebeeck.david.dgor.eazydraw;
import android.content.Intent;
import android.graphics.Color;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;
import java.util.Random;
public class workspace extends AppCompatActivity {
CustomDrawableView mCustomDrawableView;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mCustomDrawableView = new CustomDrawableView(this);
setContentView(mCustomDrawableView);
}
}
运行时的警告：
06-21 16:05:14.834 2380-2543/gorrebeeck.david.dgor.eazydraw E/Surface:getSlotFromBufferLocked: unknown buffer: 0x7ffe7a162850
06-21 16:05:14.839 2380-2543/gorrebeeck.david.dgor.eazydraw D/OpenGLRenderer: endAllStagingAnimators on 0x7ffe71d90400 (RippleDrawable) with handle 0x7ffe71d1aac0
06-21 16:05:16.719 2380-2380/gorrebeeck.david.dgor.eazydraw W/ViewRootImpl: Cancelling event due to no window focus: MotionEvent { action=ACTION_CANCEL, actionButton=0, id[0]=0, x[0]=435.89355, y[0]=759.9121, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=63310, downTime=61173, deviceId=0, source=0x1002 }
06-21 16:05:16.719 2380-2380/gorrebeeck.david.dgor.eazydraw W/ViewRootImpl: Cancelling event due to no window focus: MotionEvent { action=ACTION_CANCEL, actionButton=0, id[0]=0, x[0]=435.89355, y[0]=759.9121, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=63310, downTime=61173, deviceId=0, source=0x1002 }
06-21 16:05:16.719 2380-2380/gorrebeeck.david.dgor.eazydraw W/ViewRootImpl: Cancelling event due to no window focus: MotionEvent { action=ACTION_CANCEL, actionButton=0, id[0]=0, x[0]=435.89355, y[0]=759.9121, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=63310, downTime=61173, deviceId=0, source=0x1002 }
06-21 16:05:16.719 2380-2380/gorrebeeck.david.dgor.eazydraw W/ViewRootImpl: Cancelling event due to no window focus: MotionEvent { action=ACTION_CANCEL, actionButton=0, id[0]=0, x[0]=435.89355, y[0]=759.9121, toolType[0]=TOOL_TYPE_FINGER, buttonState=0, metaState=0, flags=0x0, edgeFlags=0x0, pointerCount=1, historySize=0, eventTime=63310, downTime=61173, deviceId=0, source=0x1002 }
这是一个示例，尝试一下
public class MainActivity extends Activity {
DrawingView dv ;
private Paint mPaint;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
dv = new DrawingView(this);
setContentView(dv);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.GREEN);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(12);
}
public class DrawingView extends View {
public int width;
public int height;
private Bitmap mBitmap;
private Canvas mCanvas;
private Path mPath;
private Paint mBitmapPaint;
Context context;
private Paint circlePaint;
private Path circlePath;
public DrawingView(Context c) {
super(c);
context=c;
mPath = new Path();
mBitmapPaint = new Paint(Paint.DITHER_FLAG);
circlePaint = new Paint();
circlePath = new Path();
circlePaint.setAntiAlias(true);
circlePaint.setColor(Color.BLUE);
circlePaint.setStyle(Paint.Style.STROKE);
circlePaint.setStrokeJoin(Paint.Join.MITER);
circlePaint.setStrokeWidth(4f);
}
@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) {
super.onDraw(canvas);
canvas.drawBitmap( mBitmap, 0, 0, mBitmapPaint);
canvas.drawPath( mPath, mPaint);
canvas.drawPath( circlePath, circlePaint);
}
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;
circlePath.reset();
circlePath.addCircle(mX, mY, 30, Path.Direction.CW);
}
}
private void touch_up() {
mPath.lineTo(mX, mY);
circlePath.reset();
// 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;
}
}
}
通过查看sdk示例中的Fingerpaint演示开始
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