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);
Android 22最小可运行的例子
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android生成的默认项目创建项目....GitHub存储库与最小的构建代码。
Android 22最小可运行的例子
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android生成的默认项目创建项目....GitHub存储库与最小的构建代码。
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);
}
}
