我试图实现以下编程方式(而不是通过XML声明):
<RelativeLayout...>
<TextView ...
android:id="@+id/label1" />
<TextView ...
android:id="@+id/label2"
android:layout_below: "@id/label1" />
</RelativeLayout>
换句话说,我如何使第二个TextView出现在第一个下面,但我想在代码中这样做:
RelativeLayout layout = new RelativeLayout(this);
TextView label1 = new TextView(this);
TextView label2 = new TextView(this);
...
layout.addView(label1);
layout.addView(label2);
setContentView(layout);
更新:
谢谢,TreeUK。我理解大致的方向,但还是不行——B和A重叠。我做错了什么?
RelativeLayout layout = new RelativeLayout(this);
TextView tv1 = new TextView(this);
tv1.setText("A");
TextView tv2 = new TextView(this);
tv2.setText("B");
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.FILL_PARENT);
lp.addRule(RelativeLayout.RIGHT_OF, tv1.getId());
layout.addView(tv1);
layout.addView(tv2, lp);
如果你真的想手动布局,我建议不要使用标准布局。这是一个kotlin的例子:
class ProgrammaticalLayout @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0) : ViewGroup(context, attrs, defStyleAttr) {
private val firstTextView = TextView(context).apply {
test = "First Text"
}
private val secondTextView = TextView(context).apply {
text = "Second Text"
}
init {
addView(firstTextView)
addView(secondTextView)
}
override fun onLayout(changed: Boolean, left: Int, top: Int, right: Int, bottom: Int) {
// center the views verticaly and horizontaly
val firstTextLeft = (measuredWidth - firstTextView.measuredWidth) / 2
val firstTextTop = (measuredHeight - (firstTextView.measuredHeight + secondTextView.measuredHeight)) / 2
firstTextView.layout(firstTextLeft,firstTextTop, firstTextLeft + firstTextView.measuredWidth,firstTextTop + firstTextView.measuredHeight)
val secondTextLeft = (measuredWidth - secondTextView.measuredWidth) / 2
val secondTextTop = firstTextView.bottom
secondTextView.layout(secondTextLeft,secondTextTop, secondTextLeft + secondTextView.measuredWidth,secondTextTop + secondTextView.measuredHeight)
}
override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
// just assume we`re getting measured exactly by the parent
val measuredWidth = MeasureSpec.getSize(widthMeasureSpec)
val measuredHeight = MeasureSpec.getSize(heightMeasureSpec)
firstTextView.measures(MeasureSpec.makeMeasureSpec(meeasuredWidth, MeasureSpec.AT_MOST), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED))
secondTextView.measures(MeasureSpec.makeMeasureSpec(meeasuredWidth, MeasureSpec.AT_MOST), MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED))
setMeasuredDimension(measuredWidth, measuredHeight)
}
}
这可能会让你知道它是如何工作的
根据我所能够拼凑的内容,您必须使用LayoutParams添加视图。
LinearLayout linearLayout = new LinearLayout(this);
RelativeLayout.LayoutParams relativeParams = new RelativeLayout.LayoutParams(
LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
relativeParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);
parentView.addView(linearLayout, relativeParams);
所有功劳都归功于sechastain,以编程方式相对定位您的项目,您必须为它们分配id。
TextView tv1 = new TextView(this);
tv1.setId(1);
TextView tv2 = new TextView(this);
tv2.setId(2);
然后addRule(使用。RIGHT_OF tv1.getId ());
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_main);
final RelativeLayout relativeLayout = new RelativeLayout(this);
final TextView tv1 = new TextView(this);
tv1.setText("tv1 is here");
// Setting an ID is mandatory.
tv1.setId(View.generateViewId());
relativeLayout.addView(tv1);
final TextView tv2 = new TextView(this);
tv2.setText("tv2 is here");
// We are defining layout params for tv2 which will be added to its parent relativelayout.
// The type of the LayoutParams depends on the parent type.
RelativeLayout.LayoutParams tv2LayoutParams = new RelativeLayout.LayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT);
//Also, we want tv2 to appear below tv1, so we are adding rule to tv2LayoutParams.
tv2LayoutParams.addRule(RelativeLayout.BELOW, tv1.getId());
//Now, adding the child view tv2 to relativelayout, and setting tv2LayoutParams to be set on view tv2.
relativeLayout.addView(tv2);
tv2.setLayoutParams(tv2LayoutParams);
//Or we can combined the above two steps in one line of code
//relativeLayout.addView(tv2, tv2LayoutParams);
this.setContentView(relativeLayout);
}
}