edittext判断输入字符长度

 

转载：

http://blog.csdn.net/liujianminghero/article/details/7092236

 

 

Android 中的EditText最大可输入字符数可以通过xml文件中为EditText设置maxLength属性或者在代码中为EditText设置LengthFilter来设置。

例如要设置EditText只能输入10个字符

xml中：

 

<EditText  android:layout_width = "fill_parent"
    android:layout_height = "wrap_content"
    android:id = "@+id/mEdit"
    android:maxLength = "10"/>

<EditText  android:layout_width = "fill_parent"
    android:layout_height = "wrap_content"
    android:id = "@+id/mEdit"
    android:maxLength = "10"/>

<EditText  android:layout_width = "fill_parent"
    android:layout_height = "wrap_content"
    android:id = "@+id/mEdit"
    android:maxLength = "10"/>

代码中：

EditText mEdit = (EditText)findViewById(R.id.mEdit);
InputFilter[] filters = {new LengthFilter(10)};
mEdit.setFilters(filters);

EditText mEdit = (EditText)findViewById(R.id.mEdit);
InputFilter[] filters = {new LengthFilter(10)};
mEdit.setFilters(filters);

EditText mEdit = (EditText)findViewById(R.id.mEdit);
InputFilter[] filters = {new LengthFilter(10)};
mEdit.setFilters(filters);

以上任意一种方法都可以满足需求，但这种方法只能为EditText设置统一的最大可输入字符，如果碰到根据实际情况限制不同的可输入字符数时，这种方法就不能用了。

比如SIM卡上的电话本姓名字段长度，纯英文下允许输入17个字符，而中文则只可以输入6个字符。此时可以重写InputFilter类来实现。

即：

EditText mEdit = (EditText)findViewById(R.id.mEdit);
InputFilter[] filters = {new AdnNameLengthFilter()};
mEdit.setFilters(filters);
public static class AdnNameLengthFilter implements InputFilter
    {
        private int nMax;

        public  CharSequence filter (CharSequence source, int start, int end, Spanned dest, int dstart, int dend)
        {
            Log.w("Android_12", "source("+start+","+end+")="+source+",dest("+dstart+","+dend+")="+dest);

            if(isChinese(dest.toString())|| isChinese(source.toString()))
            {
                nMax = LENGTH_ZNAME;
            }else
            {
                nMax =LENGTH_ENAME;
            }

                int keep = nMax - (dest.length() - (dend - dstart));

                if (keep <= 0) {
                    return "";
                } else if (keep >= end - start) {
                    return null; // keep original
                } else {
                    return source.subSequence(start, start + keep);
                }

        }
    }

EditText mEdit = (EditText)findViewById(R.id.mEdit);
InputFilter[] filters = {new AdnNameLengthFilter()};
mEdit.setFilters(filters);
public static class AdnNameLengthFilter implements InputFilter
    {
        private int nMax;

        public  CharSequence filter (CharSequence source, int start, int end, Spanned dest, int dstart, int dend)
        {
            Log.w("Android_12", "source("+start+","+end+")="+source+",dest("+dstart+","+dend+")="+dest);

            if(isChinese(dest.toString())|| isChinese(source.toString()))
            {
                nMax = LENGTH_ZNAME;
            }else
            {
                nMax =LENGTH_ENAME;
            }

                int keep = nMax - (dest.length() - (dend - dstart));

                if (keep <= 0) {
                    return "";
                } else if (keep >= end - start) {
                    return null; // keep original
                } else {
                    return source.subSequence(start, start + keep);
                }

        }
    }

EditText mEdit = (EditText)findViewById(R.id.mEdit);    	
InputFilter[] filters = {new AdnNameLengthFilter()};
mEdit.setFilters(filters);
public static class AdnNameLengthFilter implements InputFilter
	{
		private int nMax;

		public  CharSequence filter (CharSequence source, int start, int end, Spanned dest, int dstart, int dend)
		{
			Log.w("Android_12", "source("+start+","+end+")="+source+",dest("+dstart+","+dend+")="+dest);

			if(isChinese(dest.toString())|| isChinese(source.toString()))
			{
				nMax = LENGTH_ZNAME;
			}else
			{
				nMax =LENGTH_ENAME;
			}
			
	            int keep = nMax - (dest.length() - (dend - dstart));

	            if (keep <= 0) {
	                return "";
	            } else if (keep >= end - start) {
	                return null; // keep original
	            } else {
	                return source.subSequence(start, start + keep);
	            }
        
		}
	}

其中的isChinese函数是判断是否字符串中是否包含中文字符，具体实现方法就不再赘述了。

LENGTH_ZNAME : 是中文模式下允许输入的最大字符数。

LENGTH_ENAME：是纯英文模式下允许输入的最大字符数。

android怎样判断EditText输入的值是数字还是汉字 ，并限定输入字数

2011-11-25 10:37

判断汉字的方法private boolean isChinese(char c) {
        Character.UnicodeBlock ub = Character.UnicodeBlock.of(c);
        if (ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS
             || ub == Character.UnicodeBlock.CJK_COMPATIBILITY_IDEOGRAPHS
            || ub == Character.UnicodeBlock.CJK_UNIFIED_IDEOGRAPHS_EXTENSION_A
            || ub == Character.UnicodeBlock.GENERAL_PUNCTUATION
            || ub == Character.UnicodeBlock.CJK_SYMBOLS_AND_PUNCTUATION
            || ub == Character.UnicodeBlock.HALFWIDTH_AND_FULLWIDTH_FORMS) {
            return true;
        }
        return false;
    }

数字就根据unicode的范围判断吧！

 

方法一：利用TextWatcher

editText.addTextChangedListener(new TextWatcher() {  
           private CharSequence temp;  
           private boolean isEdit = true;  
           private int selectionStart ;  
           private int selectionEnd ;  
           @Override 
           public void beforeTextChanged(CharSequence s, int arg1, int arg2,  
                   int arg3) {  
               temp = s;  
           }  
             
           @Override 
           public void onTextChanged(CharSequence s, int arg1, int arg2,  
                   int arg3) {  
           }  
             
           @Override 
           public void afterTextChanged(Editable s) {  
                selectionStart = editText.getSelectionStart();  
               selectionEnd = editText.getSelectionEnd();  
               Log.i("gongbiao1",""+selectionStart);  
               if (temp.length() > Constant.TEXT_MAX) {  
                   Toast.makeText(KaguHomeActivity.this,  
                           R.string.edit_content_limit, Toast.LENGTH_SHORT)  
                           .show();  
                   s.delete(selectionStart-1, selectionEnd);  
                   int tempSelection = selectionStart;  
                   editText.setText(s);  
                   editText.setSelection(tempSelection);  
               }  
           }  
 
 
       }); 

 private TextWatcher mTextWatcher = new TextWatcher(){
  Toast mToast = null;
  public void beforeTextChanged(CharSequence s, int start,
    int count,int after) {
  }

  public void onTextChanged(CharSequence s, int start,
    int before,int count) {
  }
  
  public void afterTextChanged(Editable s) {
   int nSelStart = 0;
   int nSelEnd = 0;
   boolean nOverMaxLength = false;
   
   nSelStart = mEditText.getSelectionStart();
   nSelEnd   = mEditText.getSelectionEnd();
   
   nOverMaxLength = (s.length() > Constants.MAX_TEXT_INPUT_LENGTH) ? true : false;
   if(nOverMaxLength){
    if(null == mToast){
     mToast = Toast.makeText(mContext,
       R.string.IDS_MSG_TEXT_OVER_MAXLENGTH,
       Toast.LENGTH_SHORT);
    }
    mToast.show();
    
    s.delete(nSelStart - 1, nSelEnd);

    mEditText.setTextKeepState(s);//请读者注意这一行，保持光标原先的位置，而 mEditText.setText(s)会让光标跑到最前面，

                                                     //就算是再加mEditText.setSelection(nSelStart) 也不起作用
    }
  }
 };

方法二：利用InputFilter

    

editText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(100)});  //其中100最大输入字数 

editText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(100)});  //其中100最大输入字数

方法三：在XML中设定

Xml代码
<EditText 
    .  
    .  
    .  
    Android:maxLength="100" 
/> 

 

=========================================================

方法二：
         利用EditText可以设置filter的特性，自定义一个LengthFilter，当输入字数超过限制时 ，做出自定义的提示
          // 输入框限制输入字数
        InputFilter[] filters = new InputFilter[1];
        filters[0] = new InputFilter.LengthFilter(Constant.TEXT_MAX) {
            @Override
            public CharSequence filter(CharSequence source, int start, int end,
                    Spanned dest, int dstart, int dend) {
                if (source.length() > 0 && dest.length() == Constant.TEXT_MAX) {
                    if ((System.currentTimeMillis() - toastTime) > interval) {
                        toastTime = System.currentTimeMillis();
                        Toast
                                .makeText(KaguHomeActivity.this,
                                        R.string.edit_content_limit,
                                        Toast.LENGTH_SHORT).show();
                    }
                }
                if (dest.toString().equals(
                        getResources().getString(R.string.input_default_txt))) {
                    Bundle data = new Bundle();
                    data.putCharSequence("source", source);
                    Message message = textHandler.obtainMessage();
                    message.setData(data);
                    message.sendToTarget();
                }

                return super.filter(source, start, end, dest, dstart, dend);
            }
        };
        editText.setFilters(filters);
private Handler textHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {

            Bundle data = msg.getData();
            CharSequence source = data.getCharSequence("source");
            editText.setTextColor(Color.BLACK);
            editText.setText(source);
            editText.setSelection(source.length());
        }
    };
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