TextInputLayout使用:创建一个登陆界面

compile 'com.android.support:appcompat-v7:26.0.0-alpha1'
compile 'com.android.support:design:25.2.0'

public class MainActivity extends ActionBarActivity {
TextInputLayout usernameWrapper;
TextInputLayout passwordWrapper;
private Button btn;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
usernameWrapper = (TextInputLayout) findViewById(R.id.usernameWrapper);
passwordWrapper = (TextInputLayout) findViewById(R.id.passwordWrapper);
btn = (Button) findViewById(R.id.btn);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
hideKeyboard();
String username = usernameWrapper.getEditText().getText().toString();
String password = usernameWrapper.getEditText().getText().toString();
if (!validateEmail(username)) {
usernameWrapper.setError("Not a valid email address!");
} else if (!validatePassword(password)) {
passwordWrapper.setError("Not a valid password!");
} else {
usernameWrapper.setErrorEnabled(false);
passwordWrapper.setErrorEnabled(false);
doLogin();
}
}
});

}
private void hideKeyboard() {
View view = getCurrentFocus();
if (view != null) {
((InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE)).
hideSoftInputFromWindow(view.getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
}
}
private static final String EMAIL_PATTERN = "^[a-zA-Z0-9#_~!$&'()*+,;=:.\"(),:;<>@\\[\\]\\\\]+@[a-zA-Z0-9-]+(\\.[a-zA-Z0-9-]+)*$";
private Pattern pattern = Pattern.compile(EMAIL_PATTERN);
private Matcher matcher;

public boolean validateEmail(String email) {
matcher = pattern.matcher(email);
return matcher.matches();
}

public boolean validatePassword(String password) {
return password.length() > 5;
}

public void doLogin() {
Toast.makeText(getApplicationContext(), "OK! I'm performing login.", Toast.LENGTH_SHORT).show();
// TODO: login procedure; not within the scope of this tutorial.
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();

//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}

return super.onOptionsItemSelected(item);
}
}

<LinearLayout 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="#e3e3e3"
android:orientation="vertical"
android:padding="@dimen/activity_horizontal_margin"
>

<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0.5"
android:orientation="vertical">

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:gravity="center"
android:text="Welcome"
android:textColor="#333333"
android:textSize="30sp" />

</RelativeLayout>

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0.5"
android:orientation="vertical">
<android.support.design.widget.TextInputLayout
android:id="@+id/usernameWrapper"
android:layout_width="match_parent"
android:layout_height="wrap_content">

<EditText
android:id="@+id/username"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textEmailAddress"
android:hint="Username"/>

</android.support.design.widget.TextInputLayout>

<android.support.design.widget.TextInputLayout
android:id="@+id/passwordWrapper"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/usernameWrapper"
android:layout_marginTop="4dp">

<EditText
android:id="@+id/password"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:inputType="textPassword"
android:hint="Password"/>

</android.support.design.widget.TextInputLayout>

<Button
android:id="@+id/btn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="4dp"
android:text="Login" />

</LinearLayout>

</LinearLayout>