Question

我是Android的新手，我有两个类活动类BureauRateListing.java和适配器类CurrencySelectorAdapter.java。

所以我想从Activity类访问此变量（public String bs;）到RecyclerView Adapter方法中的onBindViewHolder()类，下面是我的Activity类：

        public String bs;
        private Intent i;

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

            raterv = (RecyclerView) findViewById(R.id.raterv_rv);
            i = getIntent();

            bs = i.getStringExtra("buysell");

}

现在我如何从 public String bs; 访问变量（Activity class）到onBindViewHolder()方法内的Adapter类，我将它作为Extra发送给NextActivity。以下是我的onBindViewHolder()方法，我想访问变量，我将其作为额外发送：

@Override
    public void onBindViewHolder(CurrencyViewHolder holder, int position) {



        final  BureauRateObject br = itemList.get(position);
        holder.bureauname.setText(br.getBureau_name());
        holder.rates.setText(br.getBuysell());

        final String BureauId = br.getBureau_id();
        final String BureauName = br.getBureau_name();
        final String BureauPhone = br.getBureau_phone();
        final String BureauEmail = br.getBureau_email();
        final String  Website = br.getWebsite();
        final String Branches = br.getBranches();
        final String BureauProfile = br.getBureau_profile();
        final String BureauLogo = br.getBureau_logo();
        final String BureauPhoto = br.getBureau_photo();
        final String currency = br.getBuysell();
        final String BuySell = "Buying";
        final String BuySell_two ="Selling";





        holder.root.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

               Intent i = new Intent(CurrencySelectorAdapter.this.context, SingleForexDetails.class);
               // i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
                i.putExtra("bureau_id", BureauId);
                i.putExtra("bureau_name",BureauName);
                i.putExtra("bureau_phone",BureauPhone);
                i.putExtra("bureau_email",BureauEmail);
                i.putExtra("website",Website);
                i.putExtra("branches",Branches);
                i.putExtra("bureau_profile",BureauProfile);
                i.putExtra("bureau_logo",BureauLogo);
                i.putExtra("bureau_photo",BureauPhoto);
                i.putExtra("currency",currency);
                i.putExtra("Buying",BuySell);
                i.putExtra("Selling",BuySell_two);
                context.startActivity(i);

            }
        });



    }

Answer 1

试试这个

BureauRateListing extends Activity{
 public String bs;
        private Intent i;

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

            raterv = (RecyclerView) findViewById(R.id.raterv_rv);
            i = getIntent();

            bs = i.getStringExtra("buysell");
       }

       public string getbs(){
         return bs;
      }
}


CurrencySelectorAdapter extends ...{

    BureauRateListing mBureauRateListing;    // it's Activity

    CurrencySelectorAdapter (Activity activity){
        mBureauRateListing =activity;
    }
    .
    .
    .

    @Override
        public void onBindViewHolder(CurrencyViewHolder holder, int position) {
          String bs = mBureauRateListing.getbs();
          .
          .
          .
    }

Answer 2

在适配器类中传递活动。

使用此语法访问Adapter中的bs变量。

BureauRateListing extends Activity{
    public String bs;
    private Intent i;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.rate_recycler_view);
        CurrencySelectorAdapter currencySelectorAdapter=new (BureauRateListing.this);
        raterv = (RecyclerView) findViewById(R.id.raterv_rv);
        i = getIntent();
        bs = i.getStringExtra("buysell");
   }}

CurrencySelectorAdapter extends ...{
Activity mBureauRateListing;    // it's Activity
CurrencySelectorAdapter (Activity activity){
    mBureauRateListing =activity;
}
@Override
    public void onBindViewHolder(CurrencyViewHolder holder, int position) {
      String bsFromActivity = ((BureauRateListing)mBureauRateListing).bs;
}}

Answer 3

最好在BureauRateListing活动中开始新活动。避免使用适配器startActivity。您可以在适配器中创建View.OnClickListener成员，在适配器setOnClickListener中为其提供相同的setter。从您的活动中，您可以直接设置此侦听器。 adapter.setOnClikListener(this)。在活动中实施View.OnClickListener，在onClick中启动新活动。

在适配器中添加

private View.OnClickListener mCLickListener;

同时添加

 public void setOnClickListener(View.OnClickListener listener){
   mCLickListener = listener;
 }

在onBindViewHolder

holder.root.setOnClickListener(mCLickListener)

制作BureauRateListingActivity工具View.OnClickListener

然后，BureauRateListingActivity内onClick方法

       Intent i = new Intent(this, SingleForexDetails.class);
           // i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            i.putExtra("bureau_id", BureauId);
            i.putExtra("bureau_name",BureauName);
            i.putExtra("bureau_phone",BureauPhone);
            i.putExtra("bureau_email",BureauEmail);
            i.putExtra("website",Website);
            i.putExtra("branches",Branches);
            i.putExtra("bureau_profile",BureauProfile);
            i.putExtra("bureau_logo",BureauLogo);
            i.putExtra("bureau_photo",BureauPhoto);
            i.putExtra("currency",currency);
            i.putExtra("Buying",BuySell);
            i.putExtra("Selling",BuySell_two);
            startActivity(i);

最后在你的BureauRateListingActivity中设置适配器中的监听器 adapter.setOnClikListener(this).

Answer 4

在适配器的构造函数中获取 BureauRateListing.java 类的实例并将其存储在成员变量中

BureauRateListing mAct;
public CurrencySelectorAdapter(BureauRateListing act){
    this.mAct = act;

}

现在，您可以使用 CurrencySelectorAdapter 类的任何方法中的mAct访问BureauRateListing 类的公共实例变量。

例如

@Override public void onBindViewHolder(CurrencyViewHolder holder, int position) { String s = mAct.bs; }

Answer 5

在MainActivity.java

public static String bs;

在RecycleViewAdapter.java中

import static <app path>.MainActivity.bs;

现在可以访问了。

从活动访问变量到RecyclerView适配器

5 个答案: