The first day to learn Android

<span style="font-size:18px;">public class MainActivity extends Activity {
public static final String TAG="MainActivity";
private EditText etName;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

Button btnClick = (Button)findViewById(R.id.btnClick);
etName=(EditText) findViewById(R.id.etname);
}
public void clickme(View view){
String name = etName.getText().toString();
Log.d(TAG,"name"+name);
Toast.makeText(MainActivity.this,"你好"+name,Toast.LENGTH_LONG)
.show();
}
}
/*

//方法一
public class MainActivity extends Activity {

public static final String TAG="MainActivity";
private EditText etName;
private Button btnClick;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//获取了事件源
btnClick = (Button)findViewById(R.id.btnClick);
btnClick.setOnClickListener(new ClickHandler());
etName=(EditText) findViewById(R.id.etname);
}
//事件处理类
class ClickHandler implements OnClickListener{

@Override
public void onClick(View v) {
String name = etName.getText().toString();
Log.d(TAG,"name"+name);
Toast.makeText(MainActivity.this,"你好"+name,Toast.LENGTH_LONG)
.show();
}
}
}*/

/*
//方法二
public class MainActivity extends Activity {
public static final String TAG="MainActivity";
private EditText etName;
private Button btnClick;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//获取了事件源
btnClick = (Button)findViewById(R.id.btnClick);
btnClick.setOnClickListener(new OnClickListener() {

public void onClick(View v){
String name = etName.getText().toString();
Log.d(TAG,"name"+name);
Toast.makeText(MainActivity.this,"你好"+name,Toast.LENGTH_LONG)
.show();
}
});

etName=(EditText) findViewById(R.id.etname);
}
}
}*/</span>

<span style="font-size:18px;"><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/bg"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity" >

<Button
android:id="@+id/btnClick"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/et_name"
android:layout_centerHorizontal="true"
android:layout_marginTop="60dp"
android:onClick="clickme"
android:text="@string/btn_Click" />

<EditText
android:id="@+id/etname"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="121dp"
android:drawableLeft="@drawable/name"
android:ems="10"
android:hint="@string/hello_world" />

</RelativeLayout></span>