如何在 Android 中验证 EditText 的输入?
androidapps/applicationsmobile development更新于 2026/1/12 2:37:17
此示例演示了如何在 Android 中验证 EditText 的输入。
步骤 1 − 在 Android Studio 中创建一个新项目，前往"文件"->"新建项目"，并填写所有必填信息以创建新项目。
步骤 2 − 将以下代码添加到 res/layout/activity_main.java
<? xml version= "1.0" encoding= "utf-8" ?> <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 :layout_margin= "16dp" tools :context= ".MainActivity" > <EditText android :id= "@+id/editText" android :layout_width= "match_parent" android :layout_height= "wrap_content" android :hint= "Enter alpha-numeric text" android :inputType= "text" tools :ignore= "Autofill" /> </RelativeLayout>
步骤 3 − 将以下代码添加到 src/ValidateFilter.java
package app.tutorialspoint.com.sample ;
import android.text.InputFilter ;
import android.text.Spanned ;
import android.util.Log ;
import java.util.regex.Matcher ;
import java.util.regex.Pattern ;
public class ValidateFilter implements InputFilter {
@Override
public CharSequence filter (CharSequence source , int start , int end , Spanned dest ,
int dstart , int dend) {
for ( int i = start ; i < end ; i++) {
String checkMe = String. valueOf (source.charAt(i)) ;
Pattern pattern =
Pattern. compile ( "[ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz123456789_]*" ) ;
Matcher matcher = pattern.matcher(checkMe) ;
boolean valid = matcher.matches() ;
if (!valid) {
Log. d ( "" , "invalid" ) ;
return "" ;
}
}
return null;
}
}
步骤 4 − 将以下代码添加到 src/MainActivity.java
package app.tutorialspoint.com.sample ;
import android.os.Bundle ;
import android.support.v7.app.AppCompatActivity ;
import android.text.InputFilter ;
import android.widget.EditText ;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate (Bundle savedInstanceState) {
super .onCreate(savedInstanceState) ;
setContentView(R.layout. activity_main ) ;
EditText editText = findViewById(R.id. editText ) ;
editText.setFilters( new InputFilter[]{ new ValidateFilter()}) ;
}
}
步骤 5 − 将以下代码添加到 AndroidManifest.xml
<? xml version= "1.0" encoding= "utf-8" ?> <manifest xmlns: android = "http://schemas.android.com/apk/res/android" package= "app.tutorialspoint.com.sample" > <uses-permission android :name= "android.permission.CALL_PHONE" /> <application android :allowBackup= "true" android :icon= "@mipmap/ic_launcher" android :label= "@string/app_name" android :roundIcon= "@mipmap/ic_launcher_round" android :supportsRtl= "true" android :theme= "@style/AppTheme" > <activity android :name= ".MainActivity" > <intent-filter> <action android :name= "android.intent.action.MAIN" /> <category android :name= "android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest>
让我们尝试运行您的应用程序。假设您已将实际的 Android 移动设备连接到电脑。要从 Android Studio 运行该应用程序，请打开项目的某个活动文件，然后点击工具栏上的"运行"图标 
。选择您的移动设备作为选项，然后勾选将显示默认屏幕的移动设备。 –
