Android自定义View

public class MyView extends View {

    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public MyView(Context context) {
        super(context);
    }
    
    @Override
    protected void onDraw(Canvas canvas) {
        // 加入绘制元素
        Paint paint = new Paint();
        paint.setTextSize(30);
        canvas.drawText("hello carloz", 0, 30, paint); //默认左下对齐
        
    }
}

<com.carloz.diycontrols.MyView 
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#00ff00"/>

canvas.drawLine(0, 60, 100, 60, paint);  //绘制直线

Rect r = new Rect(10, 90, 110, 190); //parm: int
canvas.drawRect(r, paint); // 绘制矩形

RectF rect = new RectF(10, 90, 110, 190); //parm: float
canvas.drawRect(rect, paint); // 绘制矩形

public class MyView extends View {

    Bitmap bitmap;
            
    public MyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
    }

    public MyView(Context context) {
        super(context);
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
    }
    
    @Override
    protected void onDraw(Canvas canvas) {
        // 加入绘制元素
        Paint paint = new Paint();
        paint.setTextSize(30);
        
        canvas.drawText("hello carloz", 0, 30, paint); //默认左下对齐
        
        RectF r = new RectF(10, 90, 110, 190); //parm: int
        canvas.drawRoundRect(r, 10, 10, paint); // 绘制圆角矩形
        
        paint.setColor(Color.RED); //改变图形颜色
        canvas.drawCircle(60, 270, 50, paint);    // 绘制圆， 圆心， 半径
        
        paint.setStyle(Style.STROKE);  //绘制空心的元素
        
        canvas.drawBitmap(bitmap, 10, 350, paint); //画图
    }
}

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.activity_main);
        setContentView(new MyView(this));
    }

}

public class LogicView extends View {

    Paint paint = new Paint();
    String text = "Carloz Logic View";
    private float rx = 0;
    MyThread thread;
    
    public LogicView(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
    }

    public LogicView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }

    @Override
    protected void onDraw(Canvas canvas) {
        paint.setTextSize(30);
        canvas.drawText(text, rx, 30, paint);
        
        if(thread == null ) {
            thread = new MyThread();
            thread.start();
        }
    }
    
    class MyThread extends Thread {
        @Override
        public void run() {
            // TODO Auto-generated method stub
            super.run();
            while(true) {
                rx += 5;
                if (rx > getWidth()) //超出屏幕的时候让它返回来
                    rx = 0 - paint.measureText(text); 
                
                postInvalidate(); //线程中更新绘制，重新调用onDraw方法
                try {
                    Thread.sleep(50); //速度太快肉眼看不到，要睡眠
                } catch (InterruptedException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
        }
    }
}