关于android EditText输密码时怎么把圆点改成*号

需要转换一个显示；

text.setTransformationMethod(new AsteriskPasswordTransformationMethod());

public class AsteriskPasswordTransformationMethod extends PasswordTransformationMethod {  
@Override  
public CharSequence getTransformation(CharSequence source, View view) {  
    return new PasswordCharSequence(source);  
}  

private class PasswordCharSequence implements CharSequence {  
    private CharSequence mSource;  
    public PasswordCharSequence(CharSequence source) {  
        mSource = source; // Store char sequence  
    }  
    public char charAt(int index) {  
        return '*'; // This is the important part  
    }  
    public int length() {  
        return mSource.length(); // Return default  
    }  
    public CharSequence subSequence(int start, int end) {  
        return mSource.subSequence(start, end); // Return default  
    }  
}