android - Spinner getSelectedItem() 抛出异常

标签 android android-spinner

我创建了一个带有自定义适配器的 Spinner，他看起来像这样。

enter image description here

但是，在我的 Activity 上，当我点击“保存”按钮时，我尝试 getSelectedItem() 或 getSelectedItemPosition()，抛出错误。

当执行getSelectedItem()时，会出现NullPointerException错误，而当执行getSelectedItemPosition()时，错误是Resources $NotFoundException:字符串资源 ID #0x7

遵循我的 Activity、Spinner Row 和 Spinner Adapter 的代码

FishFormActivity.java

    package br.com.vitorvillar.aquariummanager.screens;

    import android.os.Bundle;
    import android.app.Activity;
    import android.util.Log;
    import android.view.View;
    import android.widget.EditText;
    import android.widget.Spinner;
    import android.widget.Toast;

    import br.com.vitorvillar.aquariummanager.R;
    import br.com.vitorvillar.aquariummanager.adapters.FishesSpinnerAdapter;
    import br.com.vitorvillar.aquariummanager.libraries.FishTypeMap;

    public class FishFormActivity extends Activity {

        private Spinner mSpinner;
        private EditText mAmount;

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

            /** Get the The fields */
            this.mSpinner = (Spinner) this.findViewById(R.id.spinnerFishSpecies);
        this.mAmount = (EditText) this.findViewById(R.id.txtAmount);

        /** Get the FishMap */
        FishTypeMap fishType = new FishTypeMap(this);
        fishType.loadFreshWaterMap();

        /** Create and set the adapter */
        FishesSpinnerAdapter adapter = new FishesSpinnerAdapter(this, fishType);
    this.mSpinner.setAdapter(adapter);

}

public void saveFish(View view) {
    Toast.makeText(this, this.mSpinner.getSelectedItem(), Toast.LENGTH_LONG).show();
}

}

FishesSpinnerAdapter.java

package br.com.vitorvillar.aquariummanager.adapters;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.TextView;

import com.makeramen.roundedimageview.RoundedImageView;

import java.util.List;

import br.com.vitorvillar.aquariummanager.R;
import br.com.vitorvillar.aquariummanager.libraries.FishTypeMap;

public class FishesSpinnerAdapter extends BaseAdapter {

    private List<String> mNames;
    private List<String> mScientificNames;
    private List<Integer> mImages;
    private LayoutInflater mLayoutInflater;


    public FishesSpinnerAdapter(Context context, FishTypeMap fishType) {

        /** Get the values from the Fish type */
        this.mNames = fishType.getNames();
        this.mScientificNames = fishType.getScientificNames();
        this.mImages = fishType.getImages();

        /** Get the inflater layout */
        this.mLayoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public int getCount() {
        return this.mImages.size();
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            convertView = this.mLayoutInflater.inflate(R.layout.fishes_spinner_item, parent, false);
            holder = new ViewHolder();
            holder.mFishName = (TextView) convertView.findViewById(R.id.txtFishName);
            holder.mFishScientificName = (TextView) convertView.findViewById(R.id.txtFishScientificName);
            holder.mFishImage = (RoundedImageView) convertView.findViewById(R.id.fishIcon);

            /** Set the holder as tag */
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        holder.mFishName.setText(this.mNames.get(position));
        holder.mFishScientificName.setText(this.mScientificNames.get(position));
        holder.mFishImage.setImageResource(this.mImages.get(position));


        return convertView;
    }

    public static class ViewHolder {
        public RoundedImageView mFishImage;
        public TextView mFishName;
        public TextView mFishScientificName;
    }

}

fishes_spinner_item.xml

<LinearLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:paddingStart="10dp">

    <com.makeramen.roundedimageview.RoundedImageView
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/fishIcon"
        android:layout_width="60dp"
        android:layout_height="70dp"
        android:scaleType="fitCenter"
        android:src="@drawable/ic_attention"
        app:riv_border_color="#666"
        app:riv_border_width="1dp"
        app:riv_corner_radius="10dp"
        tools:ignore="ContentDescription" />
</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical"
    android:orientation="vertical"
    android:paddingStart="10dp"
    android:paddingTop="12dp">

    <TextView
        android:id="@+id/txtFishName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Molinésia"
        android:textStyle="bold" />

    <TableLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="5dp">

        <TableRow
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            tools:ignore="UselessParent">

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/txtFishScientificName"
                android:textColor="@android:color/darker_gray" />

        </TableRow>

    </TableLayout>
</LinearLayout>

这是执行 getSelectedItem() 时的错误:

04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime: FATAL EXCEPTION: main
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime: Process: br.com.vitorvillar.aquariummanager, PID: 1614
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime: java.lang.IllegalStateException: Could not execute method of the activity
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.view.View$1.onClick(View.java:4007)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.view.View.performClick(View.java:4756)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.view.View$PerformClick.run(View.java:19761)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.os.Handler.handleCallback(Handler.java:739)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:95)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:135)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5253)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:372)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:  Caused by: java.lang.reflect.InvocationTargetException
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:372)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.view.View$1.onClick(View.java:4002)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.view.View.performClick(View.java:4756) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.view.View$PerformClick.run(View.java:19761) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.os.Handler.handleCallback(Handler.java:739) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:95) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:135) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5253) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:372) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:  Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String java.lang.Object.toString()' on a null object reference
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at br.com.vitorvillar.aquariummanager.screens.FishFormActivity.saveFish(FishFormActivity.java:53)
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:372) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.view.View$1.onClick(View.java:4002) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.view.View.performClick(View.java:4756) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.view.View$PerformClick.run(View.java:19761) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.os.Handler.handleCallback(Handler.java:739) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.os.Handler.dispatchMessage(Handler.java:95) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.os.Looper.loop(Looper.java:135) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at android.app.ActivityThread.main(ActivityThread.java:5253) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Native Method) 
04-05 13:02:18.997 1614-1614/br.com.vitorvillar.aquariummanager E/AndroidRuntime:     at java.lang.reflect.Method.invoke(Method.java:372)

我创建的这个适配器没有扩展ArrayAdapter，这可能是问题所在吗？但执行 getSelectedItemPosition()

时引发错误是没有意义的

注意:当我在 onCreate() 方法中执行 getSelectedItemPosition() 时，返回位置 0。

有人可以帮助我吗？

最佳答案

when the getSelectedItemPosition() is executed the error is Resources$NotFoundException: String resource ID #0x7

发生这种情况是因为 getSelectedItemPosition() 的返回类型是 int - 因此 makeText() 方法认为它是字符串资源 ID。要正确显示位置，请使用 String.valueOf(getSelectedItemPosition()) 作为 makeText() 方法的第二个参数。

When execute the getSelectedItem() twrow a NullPointerException error

从堆栈跟踪看来，当没有选择任何项目时，您试图在 getSelectedItem() 上调用 toString() ，所以我的建议是检查是否在调用 makeText() 之前 getSelectedItem() != null。

另一个观察结果是，您在适配器内为 getItem() 返回 null。将其更改为 return mNames.get(position);

When i execute getSelectedItemPosition() inside onCreate() method, return the position 0

由于您尚未选择项目 - getSelectedItemPosition() 将返回默认值 0。

关于android - Spinner getSelectedItem() 抛出异常，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/36429047/

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