通过不断的修改BitMap来画画,需要注意的是在移动时XY坐标点需要重置.
public class MainActivity
extends AppCompatActivity
implements View.OnClickListener {
private ImageView
mImage;
/**
* 修改颜色
*/
private Button
mButColor;
/**
* 修改线宽
*/
private Button
mButLine;
private Bitmap
bitmapCopy;
private Canvas
canvas;
private Paint
paint;
/**
* 画布Canvas 画笔paint 手势识别器
* 整体思路,因为我是图片作画,实际上是对图片进行修改,起到画图的效果
* 1.原图,白纸,画布,画笔
* 2.根据手势识别进行作画
*
* @param savedInstanceState
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.
activity_main);
initView();
//加载原图
Bitmap bitmap = BitmapFactory.
decodeResource(getResources(), R.drawable.
aaa);
//做一个图片的复制
bitmapCopy = Bitmap.
createBitmap(bitmap.getWidth(), bitmap.getHeight(), bitmap.getConfig());
//创建画布
canvas =
new Canvas(
bitmapCopy);
//创建画笔
paint =
new Paint();
//开始画画
canvas.drawBitmap(bitmap,
new Matrix(),
paint);
//设置手势识别
mImage.setOnTouchListener(
new View.OnTouchListener() {
private float starty;
private float startx;
@Override
public boolean onTouch(View view, MotionEvent motionEvent) {
switch(motionEvent.getAction()){
case MotionEvent.
ACTION_DOWN:
startx = motionEvent.getX();
starty = motionEvent.getY();
break;
case MotionEvent.
ACTION_MOVE:
float x = motionEvent.getX();
float y = motionEvent.getY();
canvas.drawLine(
startx,
starty,x,y,
paint);
startx=x;
starty=y;
mImage.setImageBitmap(
bitmapCopy);
break;
default:
break;
}
return true;
}
});
}
private void initView() {
mImage = (ImageView) findViewById(R.id.
image);
mButColor = (Button) findViewById(R.id.
butColor);
mButColor.setOnClickListener(
this);
mButLine = (Button) findViewById(R.id.
butLine);
mButLine.setOnClickListener(
this);
}
//这里指示简单的修改了颜色和线宽
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.
butColor:
paint.setColor(Color.
RED);
break;
case R.id.
butLine:
paint.setStrokeWidth(
10);
// paint.setTextSize(1500);
break;
}
}
}
//保存文件
File file=new File(path,"AA");
try {
file.createNewFile();
FileOutputStream fos=new FileOutputStream(file);
bitmapCopy.compress(Bitmap.CompressFormat.JPEG,50,fos);
} catch (IOException e) {
e.printStackTrace();
}
