android - 使用 IntelliJ-Idea - 在微调器上获取 "Cannot Resolve Symbol"

Question

所以我使用 android 指南创建微调器，我可以同时创建微调器和 ArrayAdapter 对象，但是 .setDropDownViewResource(int i) 和 .setAdapter(adapter a) 方法说它们无法解析(“无法解析符号”)

package com.example.testframework;

import android.app.ListActivity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.*;
import android.widget.ArrayAdapter;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.ArrayList;
import java.util.List;

    Spinner spinner = (Spinner)findViewById(R.id.crop_spinner);
    ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.crop_array, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(17367049);
    spinner.setAdapter(adapter);


    public void onItemClick(AdapterView<?> parent, View view, int pos, long id){
        parent.getItemAtPosition(pos);
    }

    public void onNothingClicked(AdapterView<?> parent){
        parent.getFirstVisiblePosition();
    }

Answer 1

你应该在 onCreate() 方法中添加它，否则它将不起作用，例如

 protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Spinner spinner = (Spinner) findViewById(R.id.spinner);
    // Create an ArrayAdapter using the string array and a default spinner          layout
    ArrayAdapter<CharSequence> adapter =   ArrayAdapter.createFromResource(this,
            R.array.planets_array, android.R.layout.simple_spinner_item);
    // Specify the layout to use when the list of choices appears
         adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
  // Apply the adapter to the spinner
    spinner.setAdapter(adapter);

   }