Question

我正在尝试以编程方式在当前视图的中心生成一个按钮（在这种情况下是整个屏幕）。我得到屏幕的高度和宽度，然后找到屏幕的中心。然后我尝试使用LayoutParams设置顶部和左边距，考虑按钮大小 - 但结果不居中。我做错了什么？

public class StartActivity extends Activity {

private int cScreenWidth;
private int cScreenHeight;

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

    RelativeLayout ll = (RelativeLayout)findViewById(R.id.startLayout);

    Display display = getWindowManager().getDefaultDisplay(); 
    cScreenWidth = display.getWidth();  // deprecated but needed for API 10
    cScreenHeight = display.getHeight();  // deprecated but needed for API 10

    ImageButton myButton = new ImageButton(this);
    myButton.setId(100);
    myButton.setBackgroundResource(R.drawable.ic_launcher);

    int size = Math.min(cScreenWidth / 3, cScreenHeight / 3);
    LayoutParams lp = new LayoutParams( size, size );
    lp.leftMargin = (cScreenWidth / 2) - (size / 2);
    lp.topMargin = (cScreenHeight / 2) - (size / 2);
    ll.addView(myButton, lp);
}

Answer 1

尝试以下方法：

RelativeLayout.LayoutParams layoutParams = 
    (RelativeLayout.LayoutParams)myButton.getLayoutParams();
layoutParams.addRule(RelativeLayout.CENTER_IN_PARENT);
myButton.setLayoutParams(layoutParams);

这样您就不需要明确定义边距。

以编程方式居中（在屏幕中）图像按钮的最佳方法是什么？

1 个答案: