Question

在Shy Ward的宝贵帮助下，我能够为我的布局添加视图。现在，当按下第二个删除按钮（“quitar”）时，我正在尝试删除它们。我已经尝试了以下代码，但它对我不起作用：

public void quitar(View v) {
    int id = 0;
    if(!viewList.isEmpty()) {
        id = viewList.get(viewList.size()-1).getId();
        viewList.remove(id);
    } 
}

然后我认为在从列表中删除视图之前，我应该“实际删除它”。我试过这个没有好结果：

public void quitar(View v) {
    int id = 0;
    RelativeLayout panelJuego = (RelativeLayout) findViewById(R.id.panelJuego);
    Circulo circulo = new Circulo(this, 30, 30, "#000000");
    RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(100, 100);
    if(!viewList.isEmpty()) {
        id = viewList.get(viewList.size()-1).getId();
        params.addRule(id);
        panelJuego.addView(circulo, params);
        viewList.remove(id);
    } 
}

从我读过的内容中我感觉可能需要使用ArrayAdapter，但我不知道该怎么做。这将是我尝试使用ArrayAdapter但它也无法正常工作：

public class MainActivity extends Activity {
    ArrayList<Circulo> viewList = new ArrayList<Circulo>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    public void poner(View v) {
        ArrayAdapter<Circulo> adapter = new ArrayAdapter(this, R.id.panelJuego, viewList);
        RelativeLayout panelJuego = (RelativeLayout) findViewById(R.id.panelJuego);
        Circulo circulo = new Circulo(this, 30, 30, "#FF0000");
        circulo.setId(View.generateViewId());
        RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(100, 100);
        if(!viewList.isEmpty()) {
            int id = viewList.get(viewList.size()-1).getId();
            params.addRule(RelativeLayout.RIGHT_OF, id);
        } 
        panelJuego.addView(circulo, params);
        viewList.add(circulo);
        adapter.add(circulo);
        adapter.notifyDataSetChanged();
    }

    public void quitar(View v) {
        int id = 0;
        ArrayAdapter<Circulo> adapter = new ArrayAdapter(this, R.id.panelJuego, viewList);
        if(!viewList.isEmpty()) {
            adapter.remove(adapter.getItem(viewList.size()-1));
            adapter.notifyDataSetChanged();;
        } 
    }


    public class Circulo extends View {
        private int radio = 30;
        private String color;
        int Cx, Cy;

        public Circulo(Context context, int x, int y, String color) {
            super(context);
            Cx = x;
            Cy = y;
            this.color = color;
        }

        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            Paint paint = new Paint();
            paint.setStyle(Paint.Style.FILL);
            paint.setColor(Color.parseColor(color));
            canvas.drawCircle(Cx, Cy, radio, paint);
        }
    }
}

布局主要是：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <RelativeLayout
        android:id="@+id/panelJuego"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="0.76"
        android:orientation="horizontal" >

    </RelativeLayout>
    <Button
        android:id="@+id/button2"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentLeft="true"
        android:onClick="quitar"
        android:text="Quitar" />

    <Button
        android:id="@+id/button1"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_marginLeft="20dp"
        android:layout_toRightOf="@+id/button2"
        android:onClick="poner"
        android:text="Poner" />

</RelativeLayout>

我希望这有助于更好地理解我正在尝试做的事情。

Answer 1

我终于可以得到我想要做的事情，添加红色圆圈并使用两个按钮删除最后一个。代码是：

public void poner(View v) {
    RelativeLayout panelJuego = (RelativeLayout) findViewById(R.id.panelJuego);
    Circulo circulo = new Circulo(this, 30, 30, "#FF0000");
    circulo.setId(View.generateViewId());
    RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(80, 80);
    if(!viewList.isEmpty()) {
        int id = viewList.get(viewList.size()-1).getId();
        params.addRule(RelativeLayout.RIGHT_OF, id);
    } 
    panelJuego.addView(circulo, params);
    viewList.add(circulo);
    }

public void quitar(View v) {
    int id = 0;
    if(!viewList.isEmpty()) {
        id = viewList.size() - 1;
        viewList.get(id).setVisibility(View.INVISIBLE);
        viewList.remove(id);
    }
}


public class Circulo extends View {
    private int radio = 30;
    private String color;
    int Cx, Cy;

    public Circulo(Context context, int x, int y, String color) {
        super(context);
        Cx = x;
        Cy = y;
        this.color = color;
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint paint = new Paint();
        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.parseColor(color));
        canvas.drawCircle(Cx, Cy, radio, paint);
    }
}

按下按钮时，删除添加到列表视图的最后一个视图

1 个答案: