Android Spinner在运行应用程序时无法点击或工作

Question

我对编程相对陌生，最近开始使用android。我整天都在为一个旋转器的问题伤透脑筋。我读了几个类似的问题，找到了几个解决方案和例子，但都不适合我：（

package com.deitel.welcome;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.view.View;
import android.widget.AdapterView.OnItemSelectedListener;

public class Preferences extends Activity {
/** Called when the activity is first created. */
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_preferences);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.preferences, 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();
    if (id == R.id.action_profile) {
        Intent intent = new Intent(Preferences.this, Profile.class);
        startActivity(intent);
    }
    else if (id == R.id.action_home) {
        Intent intent = new Intent(Preferences.this, HomeScreen.class);
        startActivity(intent);
    }
    else if (id == R.id.action_calendar) {
        Intent intent = new Intent(Preferences.this, CalendarActivity.class);
        startActivity(intent);
    }
    else if (id == R.id.action_statistics) {
        Intent intent = new Intent(Preferences.this, Statistics.class);
        startActivity(intent);
    }
    return super.onOptionsItemSelected(item);
}
public class MainActivity extends Activity {

    private String[] states;
    private Spinner spinner;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        states = getResources().getStringArray(R.array.countries_list);
        spinner = (Spinner) findViewById(R.id.country_spinner);
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_spinner_item, states);
        dataAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        spinner.setAdapter(dataAdapter);
        spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view,
                    int position, long id) {
            }
            @Override
            public void onNothingSelected(AdapterView<?> arg0) {
            }
        });
    }
}

}

这是我的customOnItemSelected java文件：

package com.deitel.welcome;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.Toast;
public class CustomOnItemSelectedListener implements OnItemSelectedListener {
    public void onItemSelected(AdapterView<?> parent, View view, int pos,
        long id) {
        Toast.makeText(parent.getContext(), 
                "On Item Select : n" +      parent.getItemAtPosition(pos).toString(),
                Toast.LENGTH_LONG).show();
    }
    @Override
    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub
   }
}

这是我的资源文件：

<?xml version="1.0" encoding="utf-8"?>
<resources>
  <string name="spinner_prompt">Choose a country</string>
    <string-array name="country_arrays">
        <item>Malaysia</item>
        <item>United States</item>
        <item>Indonesia</item>
        <item>France</item>
        <item>Italy</item>
        <item>Singapore</item>
        <item>New Zealand</item>
        <item>India</item>
    </string-array>

</resources>

这当然是我的XML文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical"
    android:padding="10dip" >
    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dip"
        android:text="@string/country_label"
        android:textAppearance="?android:attr/textAppearanceLarge" />
    <Spinner
        android:id="@+id/country_spinner"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:prompt="@string/country_label" />
</LinearLayout>

有人能认出我做错了什么吗？

问候！Rosa

Answer 1

您的代码片段：

 spinner.setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view,
                    int position, long id) {
            }
            @Override
            public void onNothingSelected(AdapterView<?> arg0) {
            }
        });

添加没有任何逻辑的监听器，因为您没有；不要提供任何内部覆盖方法。您应该添加这样的自定义侦听器：spinner.setOnItemSelectedListener(new CustomOnItemSelectedListener())

Answer 2

您在所选的on项目中没有执行任何操作。试着在主活动的选定项上添加一条toast消息，既然可以使用默认侦听器，为什么需要创建一个自定义侦听器？

在你的主要活动中这样尝试：

spinner.setOnItemSelectedListener（新的OnItemSelectedListener（）｛

        @Override
        public void onItemSelected(AdapterView<?> parent, View view,
                int position, long id) {
Toast.makeText(parent.getContext(),"spinner clicked",
                Toast.LENGTH_LONG).show();
}
        }
        @Override
        public void onNothingSelected(AdapterView<?> arg0) {
        }
    });

只需尝试在默认侦听器中添加toast，或者设置您制作的自定义侦听器。你没有把它设置为你的听众，因此什么都没有发生。

Answer 3

简单Spinner示例和Onclick listner

 String[] tracks_time = { "3min", "5min", "10min" };
Spinner spinner_time = (Spinner)promptsView.findViewById(R.id.sp_time);
                ArrayAdapter<String> sptime = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_single_choice, tracks_time);
                spinner_time.setAdapter(sptime);
  spinner_time.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener()
            {
                @Override
                public void onItemSelected(AdapterView<?> parent, View arg1, int position ,long arg3)
                {
                  int index = parent.getSelectedItemPosition();
                  // get stuff as per index
                }
                public void onNothingSelected(AdapterView<?> arg0)
                {
                }
            });

Answer 4

谢谢大家！你是对的。。。我发现我实际上在我的活动中创建了另一个类，而在最初的活动中什么也没做。谢谢你的帮助！

我把所有的东西都复制到第一节课上，并添加了一些东西。以下是最终对我有效的代码：

public class Preferences extends Activity { 
protected CharSequence[] _options = { "Monday", "Tuesday", "Wednesday",
        "Thursday", "Friday", "Saturday", "Sunday" };
protected boolean[] _selections = new boolean[_options.length];
protected Button _optionsButton;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_preferences);
    _optionsButton = (Button) findViewById(R.id.button1);
    _optionsButton.setOnClickListener(new ButtonClickHandler());
}
public class ButtonClickHandler implements View.OnClickListener {
    public void onClick(View view) {
        showDialog(0);
    }
}
@Override
protected Dialog onCreateDialog (int id) {
            return new AlertDialog.Builder(this)
            .setTitle("Preferred Exercise Days")
            .setMultiChoiceItems(_options, _selections,
                    new DialogSelectionClickHandler())
            .setPositiveButton("OK", new DialogButtonClickHandler())
            .create();
}
}
public class DialogSelectionClickHandler implements
        DialogInterface.OnMultiChoiceClickListener {
    public void onClick(DialogInterface dialog, int clicked,
            boolean selected) {
        Log.i("ME", _options[clicked] + " selected: " + selected);
    }
}
public class DialogButtonClickHandler implements
        DialogInterface.OnClickListener {
    public void onClick(DialogInterface dialog, int clicked) {
        switch (clicked) {
        case DialogInterface.BUTTON_POSITIVE:
            String selected = "";
            int i = 0;
            for (boolean b : _selections) {
                if (b) {
                    selected += _options[i] + " ;";
                }
                i++;
            }
            printSelectedDays();
            Toast.makeText(Preferences.this, "Selected: " + selected,
                    Toast.LENGTH_SHORT).show();
            break;
        }
    }
}

protected void printSelectedDays() {
    for (int i = 0; i < _options.length; i++) {
        Log.i("ME", _options[i] + " selected: " + _selections[i]);
    }
}

解决方案有点不同，但这实际上是我最初想要实现的，所以我希望有人能使用它。