android中限制EditText最大输入字节数

需求：用户只能在输入框内输入15个字节的字符（15个英文字符或5个中文字符）

了解：一个英文字符在Android中占一个字节，一个中文字符在Android中占3个字节

代码

public class MainActivity extends AppCompatActivity {    private EditText mEditText;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mEditText = (EditText) findViewById(R.id.etInput);        mEditText.addTextChangedListener(new MyTextWatcher(this, mEditText, 15));    }    private class MyTextWatcher implements TextWatcher {        private Context context;        private EditText editText;        private int len; //允许输入的字节长度(一个中文占3个字节)        public MyTextWatcher(Context context, EditText editText, int len) {            this.context = context;            this.editText = editText;            this.len = len;        }        @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 editable) {            String inputStr = editable.toString().trim();            byte[] bytes = inputStr.getBytes();            if (bytes.length > len) {                Toast.makeText(context, "超过规定字符数", Toast.LENGTH_SHORT).show();                Log.i("str", inputStr);                //取前15个字节                byte[] newBytes = new byte[len];                for (int i = 0; i < len; i++) {                    newBytes[i] = bytes[i];                }                String newStr = new String(newBytes);                editText.setText(newStr);                //将光标定位到最后                Selection.setSelection(editText.getEditableText(), newStr.length());            }        }    }}

需求：用户只能在输入框内输入15个字节的字符（15个英文字符或5个中文字符）

代码

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