由$ P $更改同一个Java活动内容pssing按钮 [英] Changing the contents of the same Java Activity by pressing the button

问题描述

当我运行下面的code，首先我看到一个红色矩形。

但我想先看到一个绿色的长方形，然后当我preSS按钮，旁边看到同样的活动一个红色矩形。

如何解决？

MainActivity.java

 公共类MainActivity延伸活动{
Button按钮;
    绘制画;
    DRAW2 DRAW2;
    RelativeLayout的LinearLayout中;
    公共无效的onCreate（捆绑S）{
        super.onCreate（多个）;
        的setContentView（R.layout.activity_main）;        的LinearLayout =（RelativeLayout的）findViewById（R.id.t）;
按钮=（按钮）findViewById（R.id.button）; 画=新的绘图（本）;        ViewGroup.LayoutParams的LayoutParams =新ViewGroup.LayoutParams（200，200）;
        draw.setLayoutParams（的LayoutParams）;        linearLayout.addView（画）;        button.setOnClickListener（新View.OnClickListener（）{
            公共无效的onClick（视图v）{
                意向意图=新意图（MainActivity.this，Draw2.class）;
                startActivity（意向）;
            }
        }）;
        DRAW2 =新DRAW2（本）;
        draw2.setLayoutParams（的LayoutParams）;
        linearLayout.addView（DRAW2）;
    }}
 

Draw.java

 公共类抽奖扩展视图{
    涂料粉刷;    公开抽奖（上下文的背景下）{
        超级（上下文）;
        油漆=新的油漆（Paint.ANTI_ALIAS_FLAG）;
    }@覆盖
    保护无效的onDraw（帆布油画）{
    paint.setColor（Color.GREEN）;
    canvas.drawRect（50,30,100,120，油漆）;
    super.onDraw（画布）;
    }}
 

Draw2.java

 公共类DRAW2扩展视图{
    涂料粉刷;
    DRAW2（上下文的背景下）{
        超级（上下文）;
      油漆=新的油漆（）;
    }
@覆盖
    保护无效的onDraw（帆布油画）{
    paint.setColor（Color.RED）;
    canvas.drawRect（50,30,100,120，油漆）;
super.onDraw（画布）;
}
}
 

解决方案

DRAW2只是一个视图不活动，所以更改MainActivity这样

 公共类MainActivity延伸活动{
     Button按钮;
     绘制画;
     DRAW2 DRAW2;
     RelativeLayout的LinearLayout中;
     ViewGroup.LayoutParams的LayoutParams;公共无效的onCreate（捆绑S）{
    super.onCreate（多个）;
    的setContentView（R.layout.activity_main）;    的LinearLayout =（RelativeLayout的）findViewById（R.id.container）;
    按钮=（按钮）findViewById（R.id.button1）;    画=新的绘图（本）;    的LayoutParams =新ViewGroup.LayoutParams（200，200）;
    draw.setLayoutParams（的LayoutParams）;    linearLayout.addView（画）;    button.setOnClickListener（新View.OnClickListener（）{
        公共无效的onClick（视图v）{
            DRAW2 =新DRAW2（getApplicationContext（））;
            draw2.setLayoutParams（的LayoutParams）;
            linearLayout.addView（DRAW2）;
        }
    }）;}
 

}

When I run the following code, first I see a red rectangle.

But I want to see a green rectangle first, and then when I press the button, next see a red rectangle in the same activity.

What is the solution?

MainActivity.java

public class MainActivity extends Activity {
Button button;
    Draw draw;
    Draw2 draw2;
    RelativeLayout linearLayout;
    public void onCreate(Bundle s) {
        super.onCreate(s);
        setContentView(R.layout.activity_main);

        linearLayout = (RelativeLayout) findViewById(R.id.t);
button = (Button) findViewById(R.id.button);

 draw = new Draw(this);

        ViewGroup.LayoutParams layoutParams = new ViewGroup.LayoutParams(200, 200);
        draw.setLayoutParams(layoutParams);

        linearLayout.addView(draw);

        button.setOnClickListener(new View.OnClickListener() {


            public void onClick(View v) {
                Intent intent = new Intent(MainActivity.this,Draw2.class);
                startActivity(intent);
            }
        });
        draw2 = new Draw2(this);
        draw2.setLayoutParams(layoutParams);
        linearLayout.addView(draw2);
    }

}

Draw.java

public class Draw extends View {
    Paint paint;

    public Draw(Context context) {
        super(context);
        paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    }

@Override
    protected  void onDraw(Canvas canvas) {
    paint.setColor(Color.GREEN);
    canvas.drawRect(50,30,100,120,paint);
    super.onDraw(canvas);
    }}

Draw2.java

public class Draw2 extends View {
    Paint paint;
    Draw2(Context context){
        super(context);
      paint = new Paint();
    }
@Override
    protected void onDraw(Canvas canvas){
    paint.setColor(Color.RED);
    canvas.drawRect(50,30,100,120,paint);
super.onDraw(canvas);
}
}

解决方案

Draw2 is just a view not an activity,so Change MainActivity like this

public class MainActivity extends Activity {
     Button button;
     Draw draw;
     Draw2 draw2;
     RelativeLayout linearLayout;
     ViewGroup.LayoutParams layoutParams;

public void onCreate(Bundle s) {
    super.onCreate(s);
    setContentView(R.layout.activity_main);

    linearLayout = (RelativeLayout) findViewById(R.id.container);
    button = (Button) findViewById(R.id.button1);

    draw = new Draw(this);

    layoutParams = new ViewGroup.LayoutParams(200, 200);
    draw.setLayoutParams(layoutParams);

    linearLayout.addView(draw);

    button.setOnClickListener(new View.OnClickListener() {


        public void onClick(View v) {
            draw2 = new Draw2(getApplicationContext());
            draw2.setLayoutParams(layoutParams);
            linearLayout.addView(draw2);
        }
    });

}

}

这篇关于由$ P $更改同一个Java活动内容pssing按钮的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！