如何以编程方式在RelativeLayout中布局视图?

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TextView的下面，但我想在代码中做到:

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);
200710 次浏览
小开

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(RelativeLayout.RIGHT_OF, tv1.getId());

小开

调用

tv1.setId(1)

后

tv1.setText("A");
小开
长话短说: 使用相对布局，你可以在布局中放置元素

  1. 创建新的RelativeLayout。LayoutParams

    RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(...)

    (不管…填充父内容或换行内容，绝对数字(如果必须，或引用XML资源)

    2. <李> < p >添加规则: 规则指的是父级或层次结构中的其他“兄弟” 
    lp.addRule(RelativeLayout.BELOW, someOtherView.getId())
lp.addRule(RelativeLayout.ALIGN_PARENT_LEFT)

  2. Just apply the layout params: The most 'healthy' way to do that is:

    parentLayout.addView(myView, lp)

Watch out: Don't change layout from the layout callbacks. It is tempting to do so because this is when views get their actual sizes. However, in that case, unexpected results are expected.

小开

我花了4个小时来解决这个问题。终于意识到你必须不使用零作为视图id。你可能认为NO_ID == -1是允许的，但是如果你把它给你的视图，事情就会变得混乱…

小开

ViewGroup的这种方法。MarginLayoutParams为我工作:

RelativeLayout myLayout = (RelativeLayout) findViewById(R.id.my_layout);


TextView someTextView = ...


int leftMargin = Util.getXPos();
int topMargin = Util.getYPos();


RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
new ViewGroup.MarginLayoutParams(
RelativeLayout.LayoutParams.WRAP_CONTENT,
RelativeLayout.LayoutParams.WRAP_CONTENT));


lp.setMargins(leftMargin, topMargin, 0, 0);


myLayout.addView(someTextView, lp);
小开

试一试:

EditText edt = (EditText) findViewById(R.id.YourEditText);
RelativeLayout.LayoutParams lp =
new RelativeLayout.LayoutParams
(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT
);
lp.setMargins(25, 0, 0, 0); // move 25 px to right (increase left margin)
edt.setLayoutParams(lp); // lp.setMargins(left, top, right, bottom);
小开

Android 22最小可运行的例子

enter image description here

来源:

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.RelativeLayout;
import android.widget.TextView;


public class Main extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final RelativeLayout relativeLayout = new RelativeLayout(this);


final TextView tv1;
tv1 = new TextView(this);
tv1.setText("tv1");
// Setting an ID is mandatory.
tv1.setId(View.generateViewId());
relativeLayout.addView(tv1);


// tv2.
final TextView tv2;
tv2 = new TextView(this);
tv2.setText("tv2");
RelativeLayout.LayoutParams lp = new RelativeLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.FILL_PARENT);
lp.addRule(RelativeLayout.BELOW, tv1.getId());
relativeLayout.addView(tv2, lp);


// tv3.
final TextView tv3;
tv3 = new TextView(this);
tv3.setText("tv3");
RelativeLayout.LayoutParams lp2 = new RelativeLayout.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT
);
lp2.addRule(RelativeLayout.BELOW, tv2.getId());
relativeLayout.addView(tv3, lp2);


this.setContentView(relativeLayout);
}
}

使用由android create project ...生成的默认项目。GitHub存储库与最小的构建代码。

小开 
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);
}


}
小开

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


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