android EditText 字数监听并显示

在开发应用的时候，经常会限制用户输入的字数，比如发表评论或者其它什么的，下面来个简单的demo

EditText et_content;//定义一个文本输入框TextView tv_num;// 用来显示剩余字数int num = 10;//限制的最大字数 

et_content = (EditText) findViewById(R.id.et_content);tv_num = (TextView) findViewById(R.id.tv_num); tv_num.setText("10");

下面为EditText文本框添加监听

 

et_content.addTextChangedListener(new TextWatcher() {            private CharSequence temp;            private int selectionStart;            private int selectionEnd;            @Override            public void onTextChanged(CharSequence s, int start, int before,                    int count) {                temp = s;                System.out.println("s="+s);            }            @Override            public void beforeTextChanged(CharSequence s, int start, int count,                    int after) {            }            @Override            public void afterTextChanged(Editable s) {                int number = num - s.length();                tv_num.setText("" + number);                selectionStart = et_content.getSelectionStart();                selectionEnd = et_content.getSelectionEnd();                //System.out.println("start="+selectionStart+",end="+selectionEnd);                if (temp.length() > num) {                    s.delete(selectionStart - 1, selectionEnd);                    int tempSelection = selectionStart;                    et_content.setText(s);                    et_content.setSelection(tempSelection);//设置光标在最后                }            }        });

这样就可以实现了