怎么用Android画一个正方形

Question

快点啊，在线等

Answer 1

在view的onDraw(Canvas canvas))函数里画，用 canvas.drawRect(r, paint)函数
r是Rect类型的

Answer 2

package smile.FristOne;import android.app.Activity;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;public class FristOne extends Activity {
    /** Called when the activity is first created. */
SurfaceView sfv;
SurfaceHolder shv;
Button button;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        button=(Button)findViewById(R.id.button);
        sfv = (SurfaceView)findViewById(R.id.SurfaceView01);
       // button.setOnClickListener(new ButtonListener());
        Canvas canvas = shv.lockCanvas();
     Rect rect = new Rect(0,0,10,10);
     Paint mypaint = new Paint();
     mypaint.setColor(Color.BLUE);
     canvas.clipRect(rect);
     canvas.drawRect(rect, mypaint);
     shv.unlockCanvasAndPost(canvas);
    }
   
}
我是个菜鸟 这么写一定错了，帮忙看看哪里错了，应该怎么改啊？谢谢了！

Answer 3

public class CanvasDemoActivity extends Activity { @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState); setContentView(new CustomView1(this)); }
class CustomView1 extends View{ Paint paint; public CustomView1(Context context) {
super(context);
paint = new Paint(); 
paint.setColor(Color.YELLOW);
paint.setStrokeJoin(Paint.Join.ROUND);
        paint.setStrokeCap(Paint.Cap.ROUND);
        paint.setStrokeWidth(3);
}
@Override
protected void onDraw(Canvas canvas) {
                  
                //请在这里进行绘制
                        RectF rect = new RectF(50, 50, 200, 200); canvas.drawRect(rect, paint); } }}

Answer 4

paint.setStrokeJoin(Paint.Join.ROUND);
   paint.setStrokeCap(Paint.Cap.ROUND);
这两句什么意思啊？

Answer 5

我想问一下 3楼 要加Button控件的话 setContentView(new CustomView1(this));这个不应该是R.main.Button吗？他们俩冲突吗？
怎么办？