android - EditText监听输入多少个字符

说明：

案例要时刻显示EditText输入多少个字符，来挺行用户实际输入多少个字符，和还能输入几个字符。

代码：

xml：

activity:

    package com.damai.test;  
      
    import android.app.Activity;  
    import android.os.Bundle;  
    import android.text.Editable;  
    import android.text.TextWatcher;  
    import android.widget.EditText;  
    import android.widget.TextView;  
    import android.widget.Toast;  
      
    public class TestActivity extends Activity {  
        private TextView mTextView;  
        private EditText mEditText;  
        @Override  
        public void onCreate(Bundle savedInstanceState) {  
            super.onCreate(savedInstanceState);  
            setContentView(R.layout.main);  
            mTextView = (TextView)findViewById(R.id.tv);  
            mEditText = (EditText)findViewById(R.id.ET);  
            mEditText.addTextChangedListener(mTextWatcher);  
        }  
          
        TextWatcher mTextWatcher = new TextWatcher() {  
            private CharSequence temp;  
            private int editStart ;  
            private int editEnd ;  
            @Override  
            public void onTextChanged(CharSequence s, int start, int before, int count) {  
                // TODO Auto-generated method stub  
                 temp = s;  
            }  
              
            @Override  
            public void beforeTextChanged(CharSequence s, int start, int count,  
                    int after) {  
                // TODO Auto-generated method stub  
    //          mTextView.setText(s);//将输入的内容实时显示  
            }  
              
            @Override  
            public void afterTextChanged(Editable s) {  
                // TODO Auto-generated method stub  
                editStart = mEditText.getSelectionStart();  
                editEnd = mEditText.getSelectionEnd();  
                mTextView.setText("您输入了" + temp.length() + "个字符");  
                if (temp.length() > 10) {  
                    Toast.makeText(TestActivity.this,  
                            "你输入的字数已经超过了限制！", Toast.LENGTH_SHORT)  
                            .show();  
                    s.delete(editStart-1, editEnd);  
                    int tempSelection = editStart;  
                    mEditText.setText(s);  
                    mEditText.setSelection(tempSelection);  
                }  
            }  
        };  
    }