public class SystemConfig extends AppCompatActivity implements View.OnClickListener {
 private DrawerLayout configbar;
 private SharedPreferences.Editor editor;

 private EditText ip_1;
 private EditText ip_2;
 private EditText ip_3;
 private EditText ip_4;
 private Button save_ip_btn;
 String[] IP_List = null;

 @Override
 public void onClick(View v) {
 switch (v.getId()) {
 case R.id.Save_Ip:
 if (ip_1.getText().length() == 0 || ip_2.getText().length() == 0 || ip_3.getText().length() == 0 || ip_4.getText().length() == 0) {
  Toast.makeText(this, "IP地址不正确！", Toast.LENGTH_SHORT).show();
  break;
 }
 String IP_result = ip_1.getText() + "." + ip_2.getText() + "." + ip_3.getText() + "." + ip_4.getText();
 editor.putString("DB_IP", IP_result);
 editor.apply();
 Toast.makeText(this, "保存成功！", Toast.LENGTH_SHORT).show();
 break;
 default:
 break;
 }
 }

 @Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.system_config);

 SharedPreferences preferences = getSharedPreferences("System_Config", MODE_PRIVATE);
 editor = preferences.edit();
 ip_1 = (EditText) findViewById(R.id.IP_1);
 ip_2 = (EditText) findViewById(R.id.IP_2);
 ip_3 = (EditText) findViewById(R.id.IP_3);
 ip_4 = (EditText) findViewById(R.id.IP_4);
 save_ip_btn = (Button) findViewById(R.id.Save_Ip);
 save_ip_btn.setOnClickListener(this);

 TextChangeListen[] mTextWatcher = new TextChangeListen[4];
 EditText[] editTexts_List = new EditText[4];
 editTexts_List[0] = ip_1;
 editTexts_List[1] = ip_2;
 editTexts_List[2] = ip_3;
 editTexts_List[3] = ip_4;

　　　　 //循环添加监听事件
 for (int i = 0; i < 4; i++) {
 mTextWatcher[i] = new TextChangeListen(editTexts_List[i]);
 editTexts_List[i].addTextChangedListener(mTextWatcher[i]);
 }

 boolean zhaji = preferences.getBoolean("IsZhaJi", false);
 String Data_IP = preferences.getString("DB_IP", "192.168.0.118");
 IP_List = Data_IP.split("\\.");
 ip_1.setText(IP_List[0]);
 ip_2.setText(IP_List[1]);
 ip_3.setText(IP_List[2]);
 ip_4.setText(IP_List[3]);


 }

 @Override
 public boolean onOptionsItemSelected(MenuItem item) {
 switch (item.getItemId()) {
 case android.R.id.home:
 finish();
 break;
 default:
 break;
 }
 return true;
 }

 public class TextChangeListen implements TextWatcher {

 public EditText IP_Edit;

 public TextChangeListen(EditText IP_Edit) {
 super();
 this.IP_Edit = IP_Edit;
 }

 @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) {
 if (s.length() == 3) {
 if (Integer.parseInt(s.toString()) <= 255) {
  if (this.IP_Edit == ip_1) {
  ip_2.requestFocus();
  }
  if (this.IP_Edit == ip_2) {
  ip_3.requestFocus();
  }
  if (this.IP_Edit == ip_3) {
  ip_4.requestFocus();
  }
 } else {
  Toast.makeText(SystemConfig.this, "IP格式不正确！", Toast.LENGTH_SHORT).show();
  this.IP_Edit.setText("0");
 }
 } else if (s.length() == 0) {
 if (this.IP_Edit == ip_1) {
  ip_1.setText("0");
 }
 if (this.IP_Edit == ip_2) {
  ip_1.requestFocus();
  ip_2.setText("0");
 }
 if (this.IP_Edit == ip_3) {
  ip_2.requestFocus();
  ip_3.setText("0");
 }
 if (this.IP_Edit == ip_4) {
  ip_3.requestFocus();
  ip_4.setText("0");
 }
 }
 }


 }


}