Android studio实现画板功能

Canvas canvas;

ImageView imageview;

Bitmap bitmap,newbitmap;

TextView tv_stroke;

int startX, startY, endX, endY;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_my_paint_tools);

LinearLayout ll_layout = findViewById(R.id.ll_layout);

RadioGroup rg_color = findViewById(R.id.rg_color);

遍历单选按钮，当单选按钮选中时，获取单选按钮颜色并将画笔颜色设置当前按钮的文本颜色，最后注意要设置画笔宽度，以免在后面点橡皮擦的时候画笔宽度调不回来

for (int i = 0;i<rg_color.getChildCount();i++){

RadioButton rb = (RadioButton) rg_color.getChildAt(i);

rb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {

@Override

public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

if (buttonView.isChecked()){

paint.setColor(buttonView.getTextColors().getDefaultColor());

paint.setStrokeWidth(5);

}

}

});

}

首先创建一张空白图片和一张灰色画布，将图片放在画布上面

imageview = findViewById(R.id.imageview);

Log.i(“MyPaintToolsActivity”,imageview.getWidth()+" "+imageview.getHeight());

Point point = new Point();

getWindowManager().getDefaultDisplay().getSize(point);

Log.i(“MyPaintToolsActivity”,point.x+" "+point.y);

bitmap = Bitmap.createBitmap(888,1200,Bitmap.Config.ARGB_