android - 我的 2 个按钮在左下角，不知道为什么？

Question

我不知道为什么我的两个按钮在左下角？他们应该像第三个一样!我还没有发现任何错误。如果有人知道出了什么问题，那就太好了。谢谢!

在这里你可以看到它的实际外观

代码:

RelativeLayout relativeLayout = new RelativeLayout(this);

    TextView tvDate = new TextView(this);
    tvDate.setText("Date");
    tvDate.setId(R.id.tvDate);
    RelativeLayout.LayoutParams p1 = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.FILL_PARENT,
            RelativeLayout.LayoutParams.FILL_PARENT);
    tvDate.setLayoutParams(p1);
    p1.setMargins(0,30,0,0);

    tvDate.setGravity(Gravity.CENTER_HORIZONTAL);
    tvDate.setTextSize(TypedValue.COMPLEX_UNIT_SP, 25);
    relativeLayout.addView(tvDate);

    Button btNew = new Button(this);
    btNew.setId(R.id.btNew);
    btNew.setText(R.string.btNew);
    RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.WRAP_CONTENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT);
    lp.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
    lp.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
    lp.setMargins(0,120,0,0);
    lp.addRule(RelativeLayout.BELOW, R.id.tvDate);
    btNew.setLayoutParams(lp);

relativeLayout.addView(btNew);

    Button btShowTests = new Button(this);
    btShowTests.setId(R.id.btShowTests);
    btNew.setText(R.string.btShowTests);
    RelativeLayout.LayoutParams p2 = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.WRAP_CONTENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT);
    p2.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
    p2.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
    p2.setMargins(0,210,0,0);
    p2.addRule(RelativeLayout.BELOW, R.id.btNew);
    btNew.setLayoutParams(p2);

    relativeLayout.addView(btShowTests);

    Button btCheckTest = new Button(this);
    btNew.setText(R.string.btShowTests);
    btNew.setId(R.id.btCheckTest);
    RelativeLayout.LayoutParams p3 = new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.WRAP_CONTENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT);
    p3.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
    p3.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
    p3.setMargins(0,300,0,0);
    p3.addRule(RelativeLayout.BELOW, R.id.btShowTests);
    btNew.setLayoutParams(p3);

    relativeLayout.addView(btCheckTest);

    this.setContentView(relativeLayout);

Answer 1

您的代码中有两个问题。第一个是用于“日期”TextView 的 RelativeLayout.LayoutParams。你有这个:

RelativeLayout.LayoutParams p1 = new RelativeLayout.LayoutParams(
        RelativeLayout.LayoutParams.FILL_PARENT,
        RelativeLayout.LayoutParams.FILL_PARENT);

但您应该使用 WRAP_CONTENT 作为高度。如果您将其保留为 FILL_PARENT，则在解决第二个问题后，您将无法看到任何 按钮。这是因为 TextView 将填满整个屏幕，因此 BELOW 中的任何内容都将被推离屏幕。

第二个是您的代码在不应该引用的地方错误地引用了 btNew。例如:

Button btShowTests = new Button(this);
btShowTests.setId(R.id.btShowTests);
btNew.setText(R.string.btShowTests);
RelativeLayout.LayoutParams p2 = new RelativeLayout.LayoutParams(
        RelativeLayout.LayoutParams.WRAP_CONTENT,
        RelativeLayout.LayoutParams.WRAP_CONTENT);
p2.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
p2.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
p2.setMargins(0,210,0,0);
p2.addRule(RelativeLayout.BELOW, R.id.btNew);
btNew.setLayoutParams(p2);

relativeLayout.addView(btShowTests);

在这段代码中，你调用了 btNew.setText() 和 btNew.setLayoutParams()，而你应该调用 btShowTests.setText() 和 btShowTests.setLayoutParams()。你的第三个按钮有同样的问题:

Button btCheckTest = new Button(this);
btNew.setText(R.string.btShowTests);
btNew.setId(R.id.btCheckTest);
RelativeLayout.LayoutParams p3 = new RelativeLayout.LayoutParams(
        RelativeLayout.LayoutParams.WRAP_CONTENT,
        RelativeLayout.LayoutParams.WRAP_CONTENT);
p3.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
p3.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
p3.setMargins(0,300,0,0);
p3.addRule(RelativeLayout.BELOW, R.id.btShowTests);
btNew.setLayoutParams(p3);

relativeLayout.addView(btCheckTest);

本节中所有对 btNew 的引用都应替换为 btCheckTest。完成所有这些后，您的按钮将全部出现:

(请注意，第三个按钮重复使用与第二个按钮相同的字符串。您可能也想更改它。)