Android EditText输入最大长度限制如何给用户以友好的提示

EditText有个属性android:maxLength=”xxx” ，可以设置EditText的最大长度。

也可以用如下代码设置长度，editText.setFilters( new InputFilter[]{ new InputFilter.LengthFilter( 50 )});

xml布局如下：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="请输入:"
/>
<EditText
android:id="@+id/editText"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:maxLength="15"
/>
</LinearLayout>

package com.example.edittext;

import android.app.Activity;
import android.os.Bundle;
import android.text.InputFilter;
import android.text.Spanned;
import android.view.Gravity;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {

private EditText editText = null;
private Toast toast = null;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = (EditText)findViewById(R.id.editText);

editText.setFilters(new InputFilter[]{new MaxTextLengthFilter(16)});
}

class MaxTextLengthFilter implements InputFilter{

private int mMaxLength;

public MaxTextLengthFilter(int max){
mMaxLength = max - 1;
toast = Toast.makeText(MainActivity.this,"字符不能超过15个",1000);
toast.setGravity(Gravity.TOP, 0, 235);
}

public CharSequence filter(CharSequence source, int start, int end,
Spanned dest, int dstart ,int dend){
int keep = mMaxLength - (dest.length() - (dend - dstart));
if(keep < (end - start)){
toast.show();
}
if(keep <= 0){
return "";
}else if(keep >= end - start){
return null;
}else{
return source.subSequence(start,start + keep);
}
}
}
}

自定义类实现InputFilter，在filter方法中做长度判断，这样一来，当达到最大长度之后，继续输入字符的话，则每次都会弹toast提示。

出处：http://sphere.cnblogs.com

出处：/article/5317533.html