如何從GridView中獲取對象itemClick

Question

我有一個活動，名爲countryActivity和一個名爲Country的模型類。我想在模型類中設置值並將每個對象存儲在數組列表中，並在gridview中顯示對象值。當項目將被點擊，然後我想檢索對象。以下是我的代碼。我出了什麼問題或做什麼？幫助我出去嗎？

activity_country.xml

<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=".CountryActivity" > 


<TextView 
    android:id="@+id/nTextView" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentTop="true" 
    android:layout_marginLeft="21dp" 
    android:layout_marginTop="26dp" 
    android:text="Name" /> 

<TextView 
    android:id="@+id/aTextView" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignLeft="@+id/nTextView" 
    android:layout_below="@+id/nTextView" 
    android:layout_marginTop="24dp" 
    android:text="About" /> 

<EditText 
    android:id="@+id/CountryNameEditText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignBaseline="@+id/nTextView" 
    android:layout_alignBottom="@+id/nTextView" 
    android:layout_marginLeft="48dp" 
    android:layout_toRightOf="@+id/nTextView" 
    android:ems="10" > 

    <requestFocus /> 
</EditText> 

<EditText 
    android:id="@+id/CountryAboutEditText" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignLeft="@+id/CountryNameEditText" 
    android:layout_alignTop="@+id/aTextView" 
    android:ems="10" /> 

<Button 
    android:id="@+id/saveCountryButton" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignLeft="@+id/CountryAboutEditText" 
    android:layout_below="@+id/CountryAboutEditText" 
    android:layout_marginLeft="16dp" 
    android:layout_marginTop="22dp" 
    android:text="Save" 
    android:onClick="saveCountry" 
    /> 

<GridView 
    android:id="@+id/countryGridView" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_below="@+id/saveCountryButton" 
    android:layout_centerHorizontal="true" 
    android:numColumns="2"> 
</GridView> 
</RelativeLayout> 

CountryActivity.java

public class CountryActivity extends Activity 
{ 
ArrayList<Country> countries = new ArrayList<Country>(); 
Country aCountry; 

EditText CountryNameTxtBox; 
EditText CountryAboutTxtBox; 
GridView countrygGridView; 

@Override 
protected void onCreate(Bundle savedInstanceState) 
    { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_country); 
    // Show the Up button in the action bar. 

    CountryNameTxtBox = (EditText)findViewById(R.id.CountryNameEditText); 
    CountryAboutTxtBox = (EditText)findViewById(R.id.CountryAboutEditText); 
    countrygGridView = (GridView)findViewById(R.id.countryGridView); 

} 
if((txtName!="" || txtName!=null) && (txtAbout!="" || txtAbout != null)) 
    { 
     aCountry = new Country(txtName, txtAbout); 
     countries.add(aCountry); 
    } 

    showGrid(); 

} 


public void showGrid() 
{ 
    ArrayList<Country> list2 = new ArrayList<Country>(); 

    for(Country arrCountry : countries) 
    { 
      list2.add(aCountry); 

    } 


     ArrayAdapter<Country> adapter2 = new ArrayAdapter<Country>(this,android.R.layout.simple_list_item_1, list2); 
     countrygGridView.setAdapter(adapter2); 


countrygGridView.setOnItemClickListener(new OnItemClickListener() 
    { 
@Override 
public void onItemClick(AdapterView<?> parent, View v,int position, long id) 
    { 
    aCountry = (Country) v.getTag(); 
     for(Country mCountry: countries) 
     { 
     if(countries.contains(aCountry)) 
     { 
     Toast.makeText(CountryActivity.this, "match", 2000).show(); 
     } 
      } 
     } 
    }); 
    } 
} 

Country.java（模型類）

public class Country 
{ 

private String name; 
private String about; 
    ArrayList<City> cities; 

public Country() 
{ 
    cities = new ArrayList<City>(); 
} 

    public Country(String name, String about) 
{ 
    this.name= name; 
    this.about = about; 
} 


public int getNoOfCities() 
{ 
    return cities.size(); 
} 


public long getNoOfCitizens() 
{ 
     Long aPop= 0L; 
    for(City aCity: cities) 
    { 
      aPop += aCity.getPopulation(); 
    } 
    return aPop; 
} 



public String getName(){ 
    return name; 

} 
public String getAbout(){ 
    return about; 

} 
} 

Answer 1

在onItemClick方法中，只需執行list2.get(position)並且您擁有您的國家。

Answer 2

修復您的代碼

 countrygGridView.setOnItemClickListener(new OnItemClickListener() 
     { 
    @Override 
    public void onItemClick(AdapterView<?> parent, View v,int position, long id) 
     { 
       Country cnt = (Country)countrygGridView.getAdapter().getItem(position); 
     }); 
     } 

Answer 3

在onItemClick爲GridView，您將獲得該項目的位置你點擊

Country country = countries.get(position); 

Refer this

Answer 4

（在onItemClick方法，只是把：

Country aCountry = countries.get(position); 

當您在網格視圖中檢索項目時，您確實會得到一個匹配項，因爲您在適配器中設置的列表以相同順序使用，所以無需手動檢查列表。

您應該使用「equals」而不是「==」比較字符串，使用& &而不是||，因爲我想您希望所有條件同時發生並在檢查字符串的實際值之前檢查null ，所以更換：

if((txtName!="" || txtName!=null) && (txtAbout!="" || txtAbout != null)) 

有了：

if(txtName!=null && !txtName.equals("") && txtAbout != null && !txtAbout.equals("")) 

Answer 5

如果你想顯示使用名和約 ArrayAdapter，你必須重寫Country類中的toString方法。

String toString() { 
    return this.name + " " + this.about; 
}