Android中实现在矩形框中输入文字显示剩余字数的功能

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>

  
  
  
  
  

android:background="@drawable/shap" 

android:background="@null"

final int maxNum = 500;   
final TextView leftNum = (TextView) findViewById(R.id.leftNum);
EditText ed = (EditText) findViewById(R.id.nikeName);
ed.addTextChangedListener(new TextWatcher() {
  @Override
  public void beforeTextChanged(CharSequence s, int start, int count, int after) {
  }
  @Override
  public void onTextChanged(CharSequence s, int start, int before, int count) {
  }
  @Override
  public void afterTextChanged(Editable s) {
    leftNum.setText("剩余字数："+ (maxNum-s.length()));
  }
});