我正在尝试在现有类上绘制一个矩形。我见过的很多教程都创建了一个新类。但是,我收到一条错误消息,指出 Canvas 未初始化。如何初始化 Canvas ?谢谢
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_display_message);
// Get the message from the intent
Intent intent = getIntent();
Context context;
Canvas canvas;
Rect ourRect = new Rect();
ourRect.set(0,0,canvas.getWidth(),canvas.getHeight()/2);
Paint blue = new Paint();
blue.setColor(Color.BLUE);
blue.setStyle(Paint.Style.FILL);
canvas.drawRect(ourRect,blue);
}
最佳答案
初始化 Canvas 变量如下
Canvas canvas = new Canvas();
关于android - 如何在 android studio 中初始化 Canvas ?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/31665777/