1 import android.app.Activity;
 2 import android.graphics.Color;
 3 import android.os.Bundle;
 4 import android.view.ViewGroup;
 5 import android.widget.Button;
 6 import android.widget.LinearLayout;
 7 import android.widget.TextView;
 8
 9 public class MainActivity extends Activity {
10
11     private LinearLayout linearLayout;
12     private TextView textView;
13     private Button button;
14     public static final int VERTICAL = 1;
15     public static final int MATCH_PARENT = -1;
16     public static final int WRAP_CONTENT = -2;
17     @Override
18     protected void onCreate(Bundle savedInstanceState) {
19         super.onCreate(savedInstanceState);
20
21         //以编码的方式添加layout
22
23         linearLayout = new LinearLayout(this);
24         linearLayout.setOrientation(VERTICAL);  //设置LinearLayout方向，0是水平，1是垂直。默认是水平。
25         //设置布局参数，-1是MATCH_PARENT,-2是WRAP_CONTENT
26         //ViewGroup.LayoutParams(int width, int height)
27         linearLayout.setLayoutParams(new ViewGroup.LayoutParams(MATCH_PARENT,MATCH_PARENT));
28
29         textView = new TextView(this);
30         textView.setText("ThisIsATextView");
31         textView.setBackgroundColor(Color.RED);
32         textView.setLayoutParams(new ViewGroup.LayoutParams(MATCH_PARENT,WRAP_CONTENT));
33
34         button = new Button(this);
35         button.setText("ThisIsAButton");
36         button.setBackgroundColor(Color.GREEN);
37         button.setLayoutParams(new ViewGroup.LayoutParams(MATCH_PARENT,WRAP_CONTENT));
38
39         linearLayout.addView(button);
40         linearLayout.addView(textView);
41         //布局写好后，不要忘记添加到Activity中
42         setContentView(linearLayout);
43
44
45     }
46 }

 1 <!-- 确定的根元素 LinearLayout是ViewGroup的子类layout的对象 -->
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="wrap_content"
 6     android:orientation="vertical" >
 7     <!-- 添加子组件来丰富视图层 -->
 8     <Button
 9         android:layout_width="match_parent"
10         android:layout_height="wrap_content"
11         android:background="#f00"
12         android:layout_weight="1"
13         android:text="ThisIsAButton" />
14     <TextView
15         android:layout_width="match_parent"
16         android:layout_height="wrap_content"
17         android:background="#0f0"
18         android:text="ThisIsATextView"
19         />
20 </LinearLayout>