Question

我在UI中添加了两个按钮，但它们显示在另一个上面。我希望它们彼此相邻。我在这段代码中缺少什么？

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，一切都应该清楚，因为它被评论。如果你不明白，请告诉我。

Answer 2

在How to lay out Views in RelativeLayout programmatically?

中找到答案

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，重复使用控件之间的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);



    }
}

如何用一个在另一个上面的两个按钮以编程方式创建RelativeLayout？

3 个答案: