为什么我在SimpleAdapter上遇到Android运行时异常?
我试图使用实例类中的为什么我在SimpleAdapter上遇到Android运行时异常?,android,listview,exception,runtime-error,simpleadapter,Android,Listview,Exception,Runtime Error,Simpleadapter,我试图使用实例类中的simpledapter以及ListView,但每次我尝试运行程序时,都会出现运行时错误的即时崩溃。我不确定这里到底出了什么问题,但如果我将simpledapter注释掉,我就不会再收到错误,因此我不能完全确定它是否写得正确或发生了什么。整个代码如下 import java.util.ArrayList; import java.util.HashMap; import android.os.Bundle; import android.support.v7.app.Act
simpledapter
以及ListView
,但每次我尝试运行程序时,都会出现运行时错误的即时崩溃。我不确定这里到底出了什么问题,但如果我将simpledapter
注释掉,我就不会再收到错误,因此我不能完全确定它是否写得正确或发生了什么。整个代码如下
import java.util.ArrayList;
import java.util.HashMap;
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.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.SimpleAdapter;
import android.widget.Spinner;
public class Add_Item extends ActionBarActivity {
//variables
EditText TaskNameET;
Spinner SpinType;
Button SaveTodo;
String SpinnerOptions[] = {"OptionOne", "OptionTwo", "OptionThree"};
//call mainactivity class
MainActivity Main;
//array list and hashmap for the listview data storage
ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
HashMap<String, String> map = new HashMap<String, String>();
//SimpleAdapter Causing RunTime exception
SimpleAdapter ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add__item);
//define vars
TaskNameET = (EditText) findViewById(R.id.TaskNameET);
SpinType = (Spinner) findViewById(R.id.spinner1);
SaveTodo = (Button) findViewById(R.id.button1);
//adapter for spinner
ArrayAdapter<String> ard=new ArrayAdapter<String>(this,android.R.layout.simple_dropdown_item_1line, SpinnerOptions);
SpinType.setAdapter(ard);
//Arraylist for listview
// ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});
//onclick todobutton
SaveTodo.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
map.put("columnone", Add_Item.this.TaskNameET.getText().toString());
map.put("columntwo", Add_Item.this.TaskNameET.getText().toString());
map.put("columnthree", Add_Item.this.TaskNameET.getText().toString());
mylist.add(map);
Main.MainList.setAdapter(ListAdapt);
}
});
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.add__item, 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);
}
}
import java.util.ArrayList;
导入java.util.HashMap;
导入android.os.Bundle;
导入android.support.v7.app.ActionBarActivity;
导入android.view.Menu;
导入android.view.MenuItem;
导入android.view.view;
导入android.widget.ArrayAdapter;
导入android.widget.Button;
导入android.widget.EditText;
导入android.widget.simpledapter;
导入android.widget.Spinner;
公共类添加项扩展了ActionBarActivity{
//变数
编辑文本任务名;
旋转器旋转类型;
按钮SaveTodo;
字符串喷丝头选项[]={“OptionOne”、“OptionTwo”、“optionTree”};
//调用mainactivity类
主要活动主要;
//listview数据存储的数组列表和hashmap
ArrayList mylist=新的ArrayList();
HashMap=newHashMap();
//SimpleAdapter导致运行时异常
SimpleAdapter ListAdapt=new SimpleAdapter(this,mylist,R.layout.row,新字符串[]{“columnone”,“columntwo”,“columnthree”},新int[]{R.id.columnone,R.id.columntwo,R.id.columnthree});
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity\u add\u项);
//定义变量
TaskNameET=(EditText)findViewById(R.id.TaskNameET);
SpinType=(微调器)findViewById(R.id.spinner1);
SaveTodo=(按钮)findViewById(R.id.button1);
//纺纱机转接器
ArrayAdapter ard=新的ArrayAdapter(这是android.R.layout.simple\u下拉列表\u item\u 1line,喷丝头选项);
SpinType.setAdapter(ard);
//listview的Arraylist
//ListAdapt=new SimpleAdapter(this,mylist,R.layout.row,新字符串[]{“columnone”,“columntwo”,“columntwo”},新int[]{R.id.columnone,R.id.columntwo,R.id.columntwo});
//点击按钮
SaveTodo.setOnClickListener(新视图.OnClickListener(){
@凌驾
公共void onClick(视图v){
map.put(“columnone”,Add_Item.this.taskname.getText().toString());
map.put(“columntwo”,Add_Item.this.tasknamet.getText().toString());
map.put(“columntree”,Add_Item.this.taskname.getText().toString());
添加(地图);
Main.MainList.setAdapter(ListAdapt);
}
});
}
@凌驾
公共布尔onCreateOptions菜单(菜单){
//为菜单充气;这会将项目添加到操作栏(如果存在)。
getMenuInflater().充气(R.menu.add\u项,菜单);
返回true;
}
@凌驾
公共布尔值onOptionsItemSelected(菜单项项){
//处理操作栏项目单击此处。操作栏将
//自动处理Home/Up按钮上的点击,只要
//在AndroidManifest.xml中指定父活动时。
int id=item.getItemId();
if(id==R.id.action\u设置){
返回true;
}
返回super.onOptionsItemSelected(项目);
}
}
这不能在onCreate()之前
那就去吧
simpledapter listapt代码>在onCreate()外部,然后在onCreate()中
这不能在onCreate()之前
那就去吧
simpledapter listapt代码>在onCreate()外部,然后在onCreate()中
在创建活动之前,一句话,在调用onCreate之前,不能实例化您的SimpleAdapter
在onCreate中移动实例化:
SimpleAdapter ListAdapt = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add__item);
ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});
// [...]
在创建活动之前,一句话,在调用onCreate之前,不能实例化您的SimpleAdapter
在onCreate中移动实例化:
SimpleAdapter ListAdapt = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add__item);
ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});
// [...]
从堆栈跟踪中可以看出,系统组件在OnCreate()
之前不可用。因此,将简单的适配器声明移动到OnCreate()
从堆栈跟踪中可以看出,系统组件在OnCreate()
之前不可用。因此,将简单的适配器声明移动到OnCreate()
请将堆栈跟踪图像发布到logcat请将堆栈跟踪图像发布到logcat
SimpleAdapter ListAdapt = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add__item);
ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});
// [...]
//Declare it here
SimpleAdapter ListAdapt;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add__item);
ListAdapt = new SimpleAdapter(this, mylist, R.layout.row, new String[] {"columnone", "columntwo", "columnthree"}, new int[] {R.id.columnone, R.id.columntwo, R.id.columnthree});
//Rest of OnCreate
}