先来一个效果图:
activity代码(都有注释):
public class MainActivity extends AppCompatActivity {
private SurfaceView faceview;
private SurfaceHolder holder;
private Paint paint;
private Path path;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
paint = new Paint();
//设置画笔的宽高
paint.setStrokeWidth(5);
//设置画笔的颜色
path = new Path();
paint.setStyle(Paint.Style.STROKE);
paint.setColor(Color.WHITE);
holder = faceview.getHolder();
holder.addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceCreated(SurfaceHolder holder) {
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
}
});
faceview.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
float x = event.getX();
float y = event.getY();
int action = event.getAction();
switch (action) {
//点击下去的时候执行这个
case MotionEvent.ACTION_DOWN:
path.moveTo(x,y);
break;
//移动画笔的时候执行这个
case MotionEvent.ACTION_MOVE:
Canvas canvas = holder.lockCanvas();
path.lineTo(x,y);
canvas.drawPath(path,paint);
holder.unlockCanvasAndPost(canvas);
break;
//松开画笔的时候执行这个
case MotionEvent.ACTION_UP:
break;
}
return true;
}
});
}
private void initView() {
faceview = (SurfaceView) findViewById(R.id.faceview);
}
}当然,可以根据自己的喜好更改画笔的颜色和画板的颜色!