Question

我正在尝试使用seterror方法验证edittext。我正在使用焦点更改的侦听器来检查edittext的长度是否为零。但是当我尝试键入所需的edittext时，我无法输入并且文本正在输入第二个。请帮助!!

代码：

package com.example.usernamevalidation;

import android.os.Bundle;
import android.app.Activity;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.Menu;
import android.view.View;
import android.view.View.OnFocusChangeListener;
import android.widget.EditText;

public class MainActivity extends Activity {
    EditText txtusername,txtpassword;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        txtusername=(EditText) findViewById(R.id.txtusername);
        txtpassword=(EditText) findViewById(R.id.txtpassword);
        txtusername.setOnFocusChangeListener(new OnFocusChangeListener() {

            @Override
            public void onFocusChange(View v, boolean hasFocus) {
                if(!hasFocus)
                {
                    if(txtusername.getText().toString().length()==0)
                    {
                        txtusername.requestFocus();
                        txtusername.setError("Username cannot be left blank");
                    }
                }
            }
        });


    }

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

}

xml：

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    >
    <EditText
        android:layout_width="300px"
        android:layout_height="wrap_content"
        android:id="@+id/txtusername"
        />
    <EditText
        android:layout_width="300px"
        android:layout_height="wrap_content"
        android:id="@+id/txtpassword"
        />

</LinearLayout>

Answer 1

Remove this line :  txtusername.requestFocus();

Answer 2

使用TextWatcher并在onTextChanged()检查您想要的任何内容。

Answer 3

很简单，你创建了更多代码更复杂让我们试试这段代码使用TextUtils TextUtils.isEmpty - 如果字符串为null或0-length，则返回true。

EditText txtusername = (EditText) findViewById(R.id.txtusername);
EditText txtpassword = (EditText) findViewById(R.id.txtpassword);

    if(TextUtils.isEmpty(txtusername.getText().toString())){
        txtusername.setError("Username cannot be left blank");
        txtusername.requestFocus();
    }
    if(TextUtils.isEmpty(txtpassword.getText().toString())){
        txtpassword.setError("password cannot be left blank");
        txtpassword.requestFocus();
    }

   //do logging process

在android中使用seterror进行edittext验证

3 个答案: