java - 如何在 Java/Android-Studio 中绘制一个简单的可重绘矩形？

Question

我对 Java 和 Android Studio 很菜鸟，我只是找不到绘制矩形的好方法。为什么 Java 这么难？!我的 main_activity 中有一个按钮可以打开一个新 Activity 。这个:

package com.example.marty.pongtest;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Bundle;
import android.view.View;
import android.view.WindowManager;


public class GamePanelSingle extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_game_panel_single);

}

public class drawRectangle extends View{

    public drawRectangle(Context context){
        super(context);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        Rect paddle = new Rect();
        paddle.set(0, 0, canvas.getWidth()/2, canvas.getHeight()/2);

        Paint white = new Paint();
        white.setColor(Color.WHITE);
        white.setStyle(Paint.Style.FILL);

        canvas.drawRect(paddle,white);
    }
}

我的 Xml 代码:

<?xml version="1.0" encoding="utf-8"?>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:text="GameSinglePlayer"
    android:id="@+id/textView"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginLeft="55dp"
    android:layout_marginStart="55dp"
    android:layout_marginTop="22dp"
    android:textColor="#FFFFFF" />

为什么这不起作用，我该如何让它起作用？

谢谢..

Answer 1

轻松平静:

  @Override
        public void onDraw(Canvas canvas) {
            super.onDraw(canvas);

            canvas.save();

            //Draw something

            canvas.restore();
        }