Question

我的活动有一个列表视图，其中填充了我的parse.com数据库中的数据，列表确实填充没有问题。它显示名称列表。我想将列表中所选项目的名称存储在变量中并传递给另一个活动。列表会被填充，但选择错误会导致应用程序崩溃。继承人我的活动`

import java.util.List;

import android.app.ProgressDialog;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import com.parse.ParseObject;
import com.parse.ParseQuery;
import com.parse.ParseQueryAdapter;
import com.parse.ParseQueryAdapter.OnQueryLoadListener;

public class ResterauntList extends ActionBarActivity {
    String mValue;
    ArrayAdapter<String> adapter;
    ProgressDialog mProgressDialog;

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

        Bundle bdl = getIntent().getExtras();
        mValue = bdl.getString("Value");
        setContentView(R.layout.activity_resteraunt_list);

        populateList(mValue);
    }

    private void populateList(final String Value) {
        ParseQueryAdapter.QueryFactory<ParseObject> factory = new ParseQueryAdapter.QueryFactory<ParseObject>() {

            @Override
            @SuppressWarnings({ "unchecked", "rawtypes" })
            public ParseQuery create() {
                ParseQuery query = new ParseQuery("Restraunt");
                query.whereEqualTo("Location", Value);
                return query;
            }
        };
        ParseQueryAdapter<ParseObject> adapter = new ParseQueryAdapter<ParseObject>(
                this, factory);
        adapter.setTextKey("Name");
        adapter.addOnQueryLoadListener(new OnQueryLoadListener<ParseObject>() {

            public void onLoading() {
                mProgressDialog = new ProgressDialog(ResterauntList.this);
                mProgressDialog.setTitle(Value + " Restraunts Search");
                mProgressDialog.setMessage("Loading...");
                mProgressDialog.setIndeterminate(false);
                mProgressDialog.show();
            }

            public void onLoaded(List<ParseObject> objects, Exception e) {
                mProgressDialog.dismiss();
            }
        });

        final ListView listView = (ListView) findViewById(R.id.restListView);
        listView.setAdapter(adapter);
        listView.setOnItemClickListener(new OnItemClickListener() {
            public void onItemClick(AdapterView<?> parent, View view,
                    int position, long id) {
                String name = (String) listView.getItemAtPosition(position);
                Intent i = new Intent(getApplicationContext(),
                        SingleRestraunt.class);
                i.putExtra("restName", name);
                startActivity(i);

            }
        });
    }

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

此活动的我的xml如下所示

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.gastronomaapp.ResterauntList" >

    <ListView
        android:id="@+id/restListView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:clickable="true" >
    </ListView>

</RelativeLayout>

我似乎不断收到此错误

08-31 03:00:42.490: E/AndroidRuntime(2003): Process: com.example.gastronomaapp, PID: 2003
08-31 03:00:42.490: E/AndroidRuntime(2003): java.lang.ClassCastException: android.widget.LinearLayout cannot be cast to android.widget.TextView

检查了许多解决方案并尝试了几乎我能在网上找到的所有内容。绝对没有任何线索错误。非常感谢任何帮助编辑 - 堆栈跟踪，告诉我错误是在这一行。有点有直觉

String name = (String) listView.getItemAtPosition(position);
                Intent i = new Intent(getApplicationContext(),
                        SingleRestraunt.class);

Answer 1

错误发生在以下行

String name = (String) listView.getItemAtPosition(position);

您正在使用

ParseQueryAdapter<ParseObject> adapter

的内容

ArrayAdapter<String> adapter

因此您无法将其强制转换为字符串。尝试使用以下代码

ParseObject object= (ParseObject) listView.getItemAtPosition(position);

然后检查 ParseObject 的属性在putExtra中需要什么

单击listview选项时出错

1 个答案: