Android EditText 字符个数限制[转]

最新推荐文章于 2024-10-24 16:42:33 发布

转载最新推荐文章于 2024-10-24 16:42:33 发布 · 6.6k 阅读

文章标签：

#android #filter #input #null

本文介绍了两种限制Android中EditText输入字数的方法。一种是通过设置过滤器直接限制输入长度；另一种是通过TextWatcher监听文本变化并进行处理。两种方法都详细展示了如何实现，并附带了代码示例。

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Android EditText 字符个数限制

方法一：

mEditText.setFilters(new InputFilter[]{new InputFilter.LengthFilter(Constants.MAX_TEXT_INPUT_LENGTH)});

方法二：这个方法虽然复杂点，但我更偏向使用这种方法。

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
    }
  }
};

android editText 输入字数限制

2011-01-04 18:04

方法一：
         // 输入框限制输入字数
        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);
                }
            }

        });

      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());
        }
    };