如何以编程方式创建一个具有两个按钮一个在另一个之上的相对布局？

Question

我正在向 UI 添加两个按钮，但它们显示在另一个按钮之上。我希望他们出现在彼此旁边。这段代码中我缺少什么？

m_btnCrown = new ImageButton(this);
m_btnCrown.setImageResource(R.drawable.king_crown_thumb);
m_btnCrown.setAlpha(100);

RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
    RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
lp.addRule(RelativeLayout.ALIGN_PARENT_TOP);


addContentView(m_btnCrown, lp);


m_btnMonkey = new ImageButton(this);
m_btnMonkey.setImageResource(R.drawable.monkey_small);
m_btnMonkey.setAlpha(100);

lp = new RelativeLayout.LayoutParams(
    RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
lp.addRule(RelativeLayout.ALIGN_PARENT_TOP);
lp.addRule(RelativeLayout.RIGHT_OF, m_btnCrown.getId());   

addContentView(m_btnMonkey, lp);

Answer 1

我编写了一个快速示例来演示如何以编程方式创建布局。

public class CodeLayout extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        // Creating a new RelativeLayout
        RelativeLayout relativeLayout = new RelativeLayout(this);

        // Defining the RelativeLayout layout parameters.
        // In this case I want to fill its parent
        RelativeLayout.LayoutParams rlp = new RelativeLayout.LayoutParams(
                RelativeLayout.LayoutParams.FILL_PARENT,
                RelativeLayout.LayoutParams.FILL_PARENT);

        // Creating a new TextView
        TextView tv = new TextView(this);
        tv.setText("Test");

        // Defining the layout parameters of the TextView
        RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
                RelativeLayout.LayoutParams.WRAP_CONTENT,
                RelativeLayout.LayoutParams.WRAP_CONTENT);
        lp.addRule(RelativeLayout.CENTER_IN_PARENT);

        // Setting the parameters on the TextView
        tv.setLayoutParams(lp);

        // Adding the TextView to the RelativeLayout as a child
        relativeLayout.addView(tv);

        // Setting the RelativeLayout as our content view
        setContentView(relativeLayout, rlp);
    }
}

理论上，一切都应该在评论时很清楚。如果你不明白什么就告诉我。

Answer 2

在如何以编程方式在RelativeLayout中布局视图？

我们应该使用 setId() 显式设置 id。只有这样，RIGHT_OF 规则才有意义。

我犯的另一个错误是在控件之间重用layoutparams对象。我们应该为每个控件创建新对象

Answer 3

public class AndroidWalkthroughApp1 extends Activity implements View.OnClickListener {

    final int TOP_ID = 3;
    final int BOTTOM_ID = 4;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // create two layouts to hold buttons
        RelativeLayout top = new RelativeLayout(this);
        top.setId(TOP_ID);
        RelativeLayout bottom = new RelativeLayout(this);
        bottom.setId(BOTTOM_ID);

        // create buttons in a loop
        for (int i = 0; i < 2; i++) {
            Button button = new Button(this);
            button.setText("Button " + i);
            // R.id won't be generated for us, so we need to create one
            button.setId(i);

            // add our event handler (less memory than an anonymous inner class)
            button.setOnClickListener(this);

            // add generated button to view
            if (i == 0) {
                top.addView(button);
            }
            else {
                bottom.addView(button);
            }
        }

        RelativeLayout root = (RelativeLayout) findViewById(R.id.root_layout);

        // add generated layouts to root layout view
       // LinearLayout root = (LinearLayout)this.findViewById(R.id.root_layout);

        root.addView(top);
        root.addView(bottom);
    }

    @Override
    public void onClick(View v) {
        // show a message with the button's ID
        Toast toast = Toast.makeText(AndroidWalkthroughApp1.this, "You clicked button " + v.getId(), Toast.LENGTH_LONG);
        toast.show();

        // get the parent layout and remove the clicked button
        RelativeLayout parentLayout = (RelativeLayout)v.getParent();
        parentLayout.removeView(v);



    }
}