Question

我从主要活动中调用了一个活动。在活动中，我建立了数据库连接，并根据db数据填充微调器。当用户选择其中一个微调器项并按下按钮时，活动结束并将值返回到主活动（结果上的活动）。但是活动中的按钮不起作用，因此活动永远不会向主活动返回值。这是代码：

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.Spinner;
import android.widget.Toast;

public class mySpinnerClass extends Activity implements
        OnItemSelectedListener {

    private VeriTabani veritabani;
    private SQLiteDatabase db;

    Spinner spinner;

    Button btnAdd;

    String dataBaseName;
    int selectedValue;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.spinner);

        dataBaseName = "";
        selectedValue = -1;

        Intent i = getIntent();
        dataBaseName = i.getStringExtra("dataBaseName");

        veritabani = new VeriTabani(this);
        db = veritabani.getWritableDatabase();

        // Spinner element
        spinner = (Spinner) findViewById(R.id.mySpinner);

        // add button
        btnAdd = (Button) findViewById(R.id.addButton);

        // Spinner click listener
        spinner.setOnItemSelectedListener(this);

        // Loading spinner data from database
        loadSpinnerData();


        btnAdd.setOnClickListener(new View.OnClickListener() {

            public void onClick(View arg0) {

                    if (dataBaseName == "phoneOrientation") {
                        Intent intent = getIntent();
                        intent.putExtra("phoneOrientation", selectedValue);
                        setResult(RESULT_OK, intent);
                        finish();

                    }
                    else if(dataBaseName== "phonePosition") {
                        Intent intent = getIntent();
                        intent.putExtra("phonePosition", selectedValue);
                        setResult(RESULT_OK, intent);
                        finish();
                    }
                    else if(dataBaseName =="Label"){
                        Intent intent=getIntent();
                        intent.putExtra("label",selectedValue);
                        setResult(RESULT_OK, intent);
                        finish();
                    }


            }
        });
    }

    private void loadSpinnerData() {

        // Spinner Drop down elements
        List<String> lables = getAllLabels();

        // Creating adapter for spinner
        ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(this,
                android.R.layout.simple_spinner_item, lables);

        // Drop down layout style - list view with radio button
        dataAdapter
                .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        // attaching data adapter to spinner
        spinner.setAdapter(dataAdapter);
    }

    public List<String> getAllLabels() {
        List<String> labels = new ArrayList<String>();

        // Select All Query
        String selectQuery = "SELECT  * FROM " + dataBaseName;

        Cursor cursor = db.rawQuery(selectQuery, null);

        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {
                labels.add(cursor.getString(cursor.getColumnIndex("isim")));
            } while (cursor.moveToNext());
        }

        // closing connection

        // returning lables
        return labels;
    }

    public int returnID(String item) {
        int toBereturnedID;
        Cursor myCursor = db.rawQuery("SELECT _id from " +dataBaseName+ " WHERE isim="+"'"+item+"'", null);
        myCursor.moveToFirst();
        toBereturnedID = myCursor.getInt(0);
        return toBereturnedID;
    }

    public void onItemSelected(AdapterView<?> parent, View arg1, int position, long arg3) {
        // TODO Auto-generated method stub
        String label = parent.getItemAtPosition(position).toString();
        selectedValue = returnID(label);
    }

    public void onNothingSelected(AdapterView<?> arg0) {
        // TODO Auto-generated method stub

    }

}

Answer 1

尝试创建一个新的Intent而不是getIntent（）。

Intent intent=new Intent();
intent.putExtra("label",selectedValue);
setResult(RESULT_OK, intent);
finish();

希望它有所帮助。

Answer 2

您在loadSpinnerData();活动中调用onCreate()方法，因此dataBaseName始终为空，因此您希望在点击时获得微调器的值，您需要调用它在onClick()按钮方法上，它会为您提供正确的dataBaseName并使用dataBaseName.equals("phoneOrientation")代替dataBaseName == "phoneOrientation"

onClickListener在第二个活动中不起作用

2 个答案: