查看设计时,字符串数组未填充到微调器中

String-array is not populating in spinner when viewing Design

我在我的 string.xml 中添加了一个 "distance" 的字符串数组,其中包含不同距离的列表,并在我的第二个 activity 中将其应用到 Spinner 中。我还将微调器合并到第二个活动 java 文件夹中。我遇到的问题是设计中的微调器中没有填充距离。不知道是不是Java中的编码不正确,是不是显示不出来的原因。

这是strings.xml:

<string name="distancetravel">Distance willing to travel?</string>
<string-array name="distance">
    <item>Within 20 miles</item>
    <item>Within 50 miles</item>
    <item>Within 100 miles</item>
    <item>Endless Miles</item>
</string-array>

这是activity2.xml:

<RelativeLayout
  <Spinner
    android:id="@+id/distancelist"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:entries="@array/distance"
    android:layout_below="@+id/distancetravel"
    android:layout_centerInParent="true" />
</RelativeLayout>

这是Activity2.java:

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

public class Activity2 extends AppCompatActivity implements AdapterView.OnItemSelectedListener {

    Spinner spinner;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_activity2);

        spinner= (Spinner) findViewById(R.id.spinner);
        ArrayAdapter adapter=ArrayAdapter.createFromResource(this,R.array.distance,android.R.layout.simple_spinner_dropdown_item);
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(adapter);
        spinner.setOnItemSelectedListener(this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_activity2, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

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

    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {

    }
}

大多数情况下,如果未找到 R,则问题出在项目本身,某些问题未正确解决。尝试清理并重建项目,看看是否可以解决 R。如果这不起作用,请尝试将声明为字符串数组的数组传递给它

String[] foo_array = mContext.getResources().getStringArray(R.array.foo_array);

希望对您有所帮助!