java - 在另一个 Activity 中使用字符串数组将项目添加到 Spinner

Question

我尝试使用数组将项目添加到微调器中。我使用 .add(array) 但问题是，我的 Spinner 位于我的主要 Activity 中。添加已编辑文本的按钮位于其他 Activity 中。

如何将adapter.add(array)连接到我的主要 Activity ？

MainActivity.java

public class MainActivity extends AppCompatActivity {    
String selected;
Spinner spinner;
WebView myWebView;
List<CharSequence> server;
ArrayAdapter<CharSequence> adapter;

//Menu
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle item selection
    switch (item.getItemId()) {
        case R.id.add_server:
            Intent intent = new Intent(this, AddIP.class);
            this.startActivity(intent);
            return true;
        case R.id.menu_refresh:
            myWebView.reload();
            return true;
        default:
            return true;
    }
}


@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    //WebView
    myWebView = (WebView) findViewById(R.id.webView);
    myWebView.setWebViewClient(new WebC());
    WebSettings webSettings = myWebView.getSettings();

    //JavaScript erlauben
    webSettings.setJavaScriptEnabled(true);

    //Spinner
    spinner = (Spinner) findViewById(R.id.server_spinner);

    server = new ArrayList<CharSequence>();
    adapter = new ArrayAdapter<CharSequence>(this,
            R.array.server_array_name, android.R.layout.simple_spinner_item, server);

    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinner.setAdapter(adapter);
    spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {

        public void onItemSelected(AdapterView<?> parent, View view, int pos, long id) {

            selected = parent.getItemAtPosition(pos).toString();

            myWebView.loadUrl(selected);
        }

        public void onNothingSelected(AdapterView<?> parent) {

        }
    });
}

AddIP.java

public class AddIP extends AppCompatActivity {

Button btn_back, btn_add;
EditText server_ip, server_name;
String add_server_ip, add_server_name;

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.add_ip);

    server_ip = (EditText)this.findViewById(R.id.edit_server_address);
    server_name= (EditText)this.findViewById(R.id.edit_server_name);

    //Back Button
    btn_back=(Button)findViewById(R.id.btn_back);
    btn_back.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View view) {
            Intent intent = new Intent(getApplicationContext(), MainActivity.class);
            startActivity(intent);
        }
    });

    //Add IP Button
    btn_add=(Button)findViewById(R.id.btn_add);
    btn_add.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View view) {
            add_server_ip = server_ip.getText().toString();
            add_server_name= server_name.getText().toString();

            MainActivity.adapter.add(add_server_ip);
            MainActivity.adapter.add(add_server_name);

        }
    });
}
}

Answer 1

如果要将数据从第二个 Activity 传递到第一个 Activity ，请在第一个 Activity 中创建一个公共(public)方法，然后通过创建 first_activity.java 类的对象从第二个 Activity 中调用此方法。

例如First_Activity.java

public void dataAddAdapter(String text){
   adapter.add(text);
   adapter.notifydatasetchanged();
}

Second_Activity.java

First_Activity first_activity = new First_Activity();
first_activity.dataAddAdapter(Your_string_data);