1 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"2     xmlns:tools="http://schemas.android.com/tools"3     android:layout_width="match_parent"4     android:layout_height="match_parent"5     android:paddingBottom="@dimen/activity_vertical_margin"6     android:paddingLeft="@dimen/activity_horizontal_margin"7     android:paddingRight="@dimen/activity_horizontal_margin"8     android:paddingTop="@dimen/activity_vertical_margin"9     tools:context="com.example.hello.MainActivity" >
10
11     <TextView
12         android:id="@+id/textView1"
13         android:layout_width="wrap_content"
14         android:layout_height="wrap_content"
15         android:text="@string/hello_world" />
16
17     <Button
18         android:id="@+id/button1"     这个是你创建的按钮id，很重要的一个东西
19         android:layout_width="wrap_content"  //这里可以控制按钮的长度
20         android:layout_height="wrap_content" //这里可以控制按钮的高度
21         android:layout_alignLeft="@+id/textView1"
22         android:layout_below="@+id/textView1"
23         android:layout_marginTop="26dp"
24         android:text="Button" />   这里可以修改按钮的名字
25
26 </RelativeLayout>

 1 package com.example.hello;
 2
 3 import android.app.Activity;
 4 import android.app.AlertDialog;
 5 import android.os.Bundle;
 6 import android.view.Menu;
 7 import android.view.MenuItem;
 8 import android.view.View;
 9 import android.view.View.OnClickListener;
10 import android.widget.Button;
11 import android.widget.TextView;
12 import android.widget.Toast;
13
14
15 public class MainActivity extends Activity {
16
17     @Override
18     protected void onCreate(Bundle savedInstanceState) {
19         super.onCreate(savedInstanceState);
20         setContentView(R.layout.activity_main);
21
22         //定位textView1这个控件
23         TextView tv1 = (TextView) this.findViewById(R.id.textView1);
24         //对控件进行赋值，改变显示的内容
25         tv1.setText("你好，Android");
26
27         final TextView textview = (TextView)findViewById(R.id.textView2);
28         //根据id获取按钮的控件
29         Button btn = (Button) this.findViewById(R.id.button1);
30         //修改按钮的名字
31         btn.setText("点我");
32         //给按钮赋予点击事件
33        34         btn.setOnClickListener(new OnClickListener() {
36             @Override
37
38             public void onClick(View v) {
39
45                 //第一个参数：上下文，指的是activity，所以写的是MainActivity.this
46                 //第二个参数：设置弹出的信息
47                 //第三个参数，设置显示的实践
48                 Toast.makeText(MainActivity.this, "点解要点我", Toast.LENGTH_LONG).show();
49             }
50         });
51     }
52
53
54     @Override
55     public boolean onCreateOptionsMenu(Menu menu) {
56         // Inflate the menu; this adds items to the action bar if it is present.
57         getMenuInflater().inflate(R.menu.main, menu);
58         return true;
59     }
60
61     @Override
62     public boolean onOptionsItemSelected(MenuItem item) {
63         // Handle action bar item clicks here. The action bar will
64         // automatically handle clicks on the Home/Up button, so long
65         // as you specify a parent activity in AndroidManifest.xml.
66         int id = item.getItemId();
67         if (id == R.id.action_settings) {
68             return true;
69         }
70         return super.onOptionsItemSelected(item);
71     }
72 }

 1 package com.example.hello;
 2
 3 import android.content.Context;
 4 import android.view.View;
 5 import android.view.View.OnClickListener;
 6 import android.widget.Toast;
 7
 8 public class btnClickListen implements OnClickListener {
 9
10     private Context context;
11
12     public btnClickListen (Context c) {
13         this.context = c;
14     }
15
16
17     @Override
18     public void onClick(View v) {
19         Toast t = Toast.makeText(context, "点解要点我", Toast.LENGTH_LONG);
20         t.show();
21
22     }
23
24 }

 1 package com.example.hello;
 2
 3 import android.app.Activity;
 4 import android.app.AlertDialog;
 5 import android.os.Bundle;
 6 import android.view.Menu;
 7 import android.view.MenuItem;
 8 import android.view.View;
 9 import android.view.View.OnClickListener;
10 import android.widget.Button;
11 import android.widget.TextView;
12 import android.widget.Toast;
13
14
15 public class MainActivity extends Activity {
16
17     @Override
18     protected void onCreate(Bundle savedInstanceState) {
19         super.onCreate(savedInstanceState);
20         setContentView(R.layout.activity_main);
21
22         //定位textView1这个控件
23         TextView tv1 = (TextView) this.findViewById(R.id.textView1);
24         //对控件进行赋值，改变显示的内容
25         tv1.setText("你好，Android");
26
27         final TextView textview = (TextView)findViewById(R.id.textView2);
28         //根据id获取按钮的控件
29         Button btn = (Button) this.findViewById(R.id.button1);
30         //修改按钮的名字
31         btn.setText("点我");
32         //给按钮赋予点击事件
33         btn.setOnClickListener( new btnClickListen(this));
34
35     }
36
37
38     @Override
39     public boolean onCreateOptionsMenu(Menu menu) {
40         // Inflate the menu; this adds items to the action bar if it is present.
41         getMenuInflater().inflate(R.menu.main, menu);
42         return true;
43     }
44
45     @Override
46     public boolean onOptionsItemSelected(MenuItem item) {
47         // Handle action bar item clicks here. The action bar will
48         // automatically handle clicks on the Home/Up button, so long
49         // as you specify a parent activity in AndroidManifest.xml.
50         int id = item.getItemId();
51         if (id == R.id.action_settings) {
52             return true;
53         }
54         return super.onOptionsItemSelected(item);
55     }
56 }