Android EditText输入框实现下拉且保存最近5个历史记录思路详解

s_btnDown.setOnClickListener(this);                           //对其进行焦点监听

case R.id.btnDown:
          showListPopulWindow();                          //调用显示PopuWindow 函数
      break;

private void showListPopulWindow() {
        final DeviceKeySecretManager list = ((MainActivity)getActivity()).deviceKeySecretManager;//要填充的数据
        final ListPopupWindow listPopupWindow;
        listPopupWindow = new ListPopupWindow(getActivity());
        listPopupWindow.setAdapter(new ArrayAdapter<String>(getActivity(), android.R.layout.simple_list_item_1, list.getKeyList()));//用android内置布局，或设计自己的样式
        listPopupWindow.setAnchorView(s_etAppKey);          //以哪个控件为基准，在该处以mEditText为基准
        listPopupWindow.setModal(true);

        listPopupWindow.setOnItemClickListener(new AdapterView.OnItemClickListener() {          //设置项点击监听
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
                if (list.KeySecretSum==i){
                    list.Clear();                                                           //点击清空
                    s_etAppKey.setText("");                            //把选择的选项内容展示在EditText上
                    s_etAppSecret.setText("");
                }else{
                    s_etAppKey.setText(list.getKeyList()[i]);                            //把选择的选项内容展示在EditText上
                    s_etAppSecret.setText(list.getSecretList()[i]);
                }

                listPopupWindow.dismiss();                             //如果已经选择了，隐藏起来
            }
        });
        listPopupWindow.show();                  //把ListPopWindow展示出来
    }

/**
 * 标识和密钥管理
 * 最多只存储5个密钥，超过5个就开始进行循环覆盖(从第一个开始)。
 */
class DeviceKeySecretManager {

    public DeviceKeySecretManager() {
        CurrentSaveIndex = 0;
    }

    public String[] getKeyList() {
        return KeyList;
    }

    public String[] getSecretList() {
        return SecretList;
    }

    /**
     * 添加新到的key和secret到密钥库
     * 1、先判断密钥库中是否存在key，如果存在则直接更新其secret值，
     * 2、不存在则直接进行添加key/secret值。
     */
    public void addBufferKeyAndSecret(String key, String secret) {
        if (IntegerConversion.UseLoop(KeyList,key)) {
            int index=0;
            for (int i=0;i<KeyList.length;i++) {
                if (KeyList[i].equals(key)){
                    index=i;
                    break;
                }
            }
            KeyList[index]=key;
            SecretList[index]=secret;
        } else {
            if (KeySecretSum == 5) {
                CurrentSaveIndex = CurrentSaveIndex == 5 ? 0 : CurrentSaveIndex;
                KeyList[CurrentSaveIndex] = key;
                SecretList[CurrentSaveIndex] = secret;
                CurrentSaveIndex++;
            } else {
                KeyList[CurrentSaveIndex] = key;
                SecretList[CurrentSaveIndex] = secret;
                CurrentSaveIndex++;
                KeySecretSum++;
                KeyList[CurrentSaveIndex] = "清空历史记录";
            }
        }
    }

    public void Clear() {
        CurrentSaveIndex = 0;
        KeySecretSum = 0;

        for (int i = 0; i < KeyList.length; i++) {
            KeyList[i] = null;
        }

        for (int i = 0; i < SecretList.length; i++) {
            SecretList[i] = null;
        }
    }

    public int CurrentSaveIndex = 0;                    //当前保存的序号
    public int KeySecretSum = 0;                        //key的总个数，最多存储5个。
    private String[] KeyList = new String[6];
    private String[] SecretList = new String[5];
}

/**
     * 读取保存的文件
     */
    private void getSavedPreference() {
        try {
            SharedPreferences pref = this.getSharedPreferences(getResources().getString(R.string.app_name), MODE_PRIVATE);
            int sum=pref.getInt("KeySecretSum", 0);

            for (int i=0;i<=sum;i++){
                deviceKeySecretManager.getKeyList()[i]=pref.getString("Key"+i, "");
            }

            for (int i=0;i<sum;i++){
                deviceKeySecretManager.getSecretList()[i]=pref.getString("Secret"+i, "");
            }

            deviceKeySecretManager.CurrentSaveIndex=sum==5?0:sum;
            deviceKeySecretManager.KeySecretSum=sum;
        } catch (Exception ex) {

        }
    }

    /**
     * 保存文件
     * */
    private void setSavePreference() {
        try {
            SharedPreferences pref = getSharedPreferences(getResources().getString(R.string.app_name), MODE_PRIVATE);
            SharedPreferences.Editor edit = pref.edit();
            edit.putInt("KeySecretSum", deviceKeySecretManager.KeySecretSum);             //现有保存的总个数

            for (int i=0;i<=deviceKeySecretManager.KeySecretSum;i++){
                edit.putString("Key"+i, deviceKeySecretManager.getKeyList()[i]);
            }

            for (int i=0;i<deviceKeySecretManager.KeySecretSum;i++){
                edit.putString("Secret"+i, deviceKeySecretManager.getSecretList()[i]);
            }
            edit.commit();
        } catch (Exception ex) {

        }
    }

@Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.btnSendData:
                if (!DeviceManager.getInstance().DeviceIsConnected()) {
                    tu.ToastShow(context, "设备已断开连接，无法进行通讯。");
                    return;
                }
                if (DeviceManager.getInstance().DeviceIsBusy()) {
                    tu.ToastShow(context, "设备忙碌，请等待...");
                    return;
                }
                try {
                    String key,secret;
                    key=s_etAppKey.getText().toString();
                    secret=s_etAppSecret.getText().toString();

                    if (key.length()<=0||secret.length()<=0||
                            TextUtils.isEmpty(key)||TextUtils.isEmpty(secret)){
                        tu.ToastShow(context, "标识和密钥不能为空！");
                        return;
                    }

                    //调用方法拼接字符串，发送给下位机设备。
                    int nResult = DeviceManager.getInstance().WriteRTKData(context, new byte[]{});
                    if (nResult > 0) {
                        tu.ToastShow(context, "参数写入成功");

                        ((MainActivity)getActivity()).deviceKeySecretManager.addBufferKeyAndSecret(key,secret);
                    }
                } catch (Exception ex) {
                    tu.ToastShow(context, "参数写入失败！");
                }
                break;
            case R.id.btnClearData:                                     //只清空当前的标识和密钥
                s_etAppKey.setText("");
                s_etAppSecret.setText("");
                break;
            case R.id.btnDown:
                showListPopulWindow();                          //调用显示PopuWindow 函数
                break;
            default:
                break;
        }
    }