Android 在 Android 中设置 Spinner 值

Question

我正在研究 android spinner 并陷入了一个简单的问题，但尝试了很多但无法解决它。 spinner.setselection 不工作。这是代码。这是微调器集选择的简单直接代码，但给了我致命错误 ArrayIndexOutOfBound 异常。

package com.example.younastraders;

import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import com.toptoche.searchablespinnerlibrary.SearchableSpinner;

public class Test extends AppCompatActivity {
    SearchableSpinner edDealerID;
    Button btnAdd;
    ArrayAdapter<String> dealerAdapter;
    public String[] dealersName;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.fragment_add_return);
        dealersName = new String[5];
        dealersName[0] = "Dealer 1";
        dealersName[1] = "Dealer 2";
        dealersName[2] = "Dealer 3";
        dealersName[3] = "Dealer 4";
        dealersName[4] = "Dealer 5";
        btnAdd = findViewById(R.id.button_add);
        edDealerID = findViewById(R.id.ed_dealerName);

        dealerAdapter = new ArrayAdapter<>(Test.this, android.R.layout.simple_spinner_dropdown_item, dealersName);
        edDealerID.setAdapter(dealerAdapter);

        btnAdd.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edDealerID.setSelection(1);
            }
        });
    }
}

总是发生的错误如下所示。

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.younastraders, PID: 8996
    java.lang.ArrayIndexOutOfBoundsException: length=1; index=1
        at java.util.Arrays$ArrayList.get(Arrays.java:3766)
        at android.widget.ArrayAdapter.getItem(ArrayAdapter.java:397)
        at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:453)
        at android.widget.ArrayAdapter.getView(ArrayAdapter.java:419)
        at android.widget.Spinner.makeView(Spinner.java:724)
        at android.widget.Spinner.layout(Spinner.java:672)
        at android.widget.Spinner.onLayout(Spinner.java:634)
        at android.view.View.layout(View.java:21912)
        at android.view.ViewGroup.layout(ViewGroup.java:6260)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
        at android.view.View.layout(View.java:21912)
        at android.view.ViewGroup.layout(ViewGroup.java:6260)
        at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1915)
        at android.view.View.layout(View.java:21912)
        at android.view.ViewGroup.layout(ViewGroup.java:6260)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
        at android.view.View.layout(View.java:21912)
        at android.view.ViewGroup.layout(ViewGroup.java:6260)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
        at android.view.View.layout(View.java:21912)
        at android.view.ViewGroup.layout(ViewGroup.java:6260)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
        at android.view.View.layout(View.java:21912)
        at android.view.ViewGroup.layout(ViewGroup.java:6260)
        at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
        at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
        at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
        at android.view.View.layout(View.java:21912)
        at android.view.ViewGroup.layout(ViewGroup.java:6260)
        at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
        at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
        at com.android.internal.policy.DecorView.onLayout(DecorView.java:779)
        at android.view.View.layout(View.java:21912)
        at android.view.ViewGroup.layout(ViewGroup.java:6260)
        at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3080)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2590)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1721)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7598)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:966)
        at android.view.Choreographer.doCallbacks(Choreographer.java:790)
        at android.view.Choreographer.doFrame(Choreographer.java:725)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:951)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7356)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)

请有人帮助我。提前谢谢你。

Answer 1

试试这个 -> 交换第二个和第三个参数的位置，像这样：

dealerAdapter = new ArrayAdapter<>(Test.this,
                      dealersName, android.R.layout.simple_spinner_dropdown_item);
        edDealerID.setAdapter(dealerAdapter);

如果上面没有问题，无论如何在上面的代码后面添加这一行：

dealeradapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

这可能会有所帮助：Android: setSelection having no effect on Spinner

希望对你有帮助。