MainActivity：
/**
* 点击EditText窗体后，清除预设字
* @author lichao829@163.com
*
*/
public class MainActivity extends Activity{
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
EditText username = (EditText)findViewById(R.id.username);
EditText password = (EditText)findViewById(R.id.password);
Button login = (Button)findViewById(R.id.login);
/*EditText默认获取焦点行为的取消？
解决之道：在EditText的父级控件中，
设置： android:focusable="true"
android:focusableInTouchMode="true"
详见xml布局文件。*/
//username焦点监听事件
username.setOnFocusChangeListener(new OnFocusChangeListener() {
public void onFocusChange(View v, boolean hasFocus) {
EditText et=(EditText)v;
if (!hasFocus) {// 失去焦点
et.setHint(et.getTag().toString());
} else {
String hint=et.getHint().toString();
et.setTag(hint);//保存预设字
et.setHint(null);
}
}
});
//password焦点监听事件
password.setOnFocusChangeListener(new OnFocusChangeListener() {
public void onFocusChange(View v, boolean hasFocus) {
EditText et=(EditText)v;
if (!hasFocus) {// 失去焦点
et.setHint(et.getTag().toString());
} else {
String hint=et.getHint().toString();
et.setTag(hint);//保存预设字
et.setHint(null);
}
}
});
login.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Toast.makeText(MainActivity.this, "登录", Toast.LENGTH_LONG).show();
}
});
}
}
布局界面：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="8dp"
android:focusable="true"
android:focusableInTouchMode="true"
android:orientation="vertical" >
<EditText
android:id="@+id/username"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入您的用户名"/>
<EditText
android:id="@+id/password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入您的密码"/>
<Button
android:id="@+id/login"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="登录"/>
</LinearLayout>
