Android無法在列表視圖中突出顯示一個項目

我試圖在listview中突出顯示一個項目，因此當用戶點擊listview中的某個項目時 - 啓動了一個新的活動，並且突出顯示了該項目中的特定項目。Android無法在列表視圖中突出顯示一個項目

我知道這可以用碎片完成，但我更喜歡活動，因爲它使我的工作更輕鬆。

因此，這裏的自定義適配器

public class CustomAdapter extends BaseAdapter{ 

    Context mycontext; 
    ArrayList<String> contactsList; 
    LayoutInflater minflater; 

    public CustomAdapter(Context context, ArrayList<String> list) 
    { 
     this.mycontext=context; 
     contactsList=list; 
     minflater =LayoutInflater.from(context); 

    } 
    @Override 
    public int getCount() 
    { 
     return contactsList.size(); 
    } 


    @Override 
    public Object getItem(int position) 
    { 
     return contactsList.get(position); 
    } 


    @Override 
    public long getItemId(int position) { 
     // TODO Auto-generated method stub 
     return position; 
    } 


    @Override 
    public View getView(int position,View convertView,ViewGroup parent) 
    { 
     View v=convertView; 

     if (convertView !=null) 
     { 
      LayoutInflater inflater=(LayoutInflater) mycontext.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      v =inflater.inflate(R.layout.item_layout,null); 

      TextView tv=(TextView)v.findViewById(R.id.itemName); 

      if (position ==1) 
      { 
       convertView.setBackgroundColor(Color.BLUE); 

      } 
     } 
     return convertView; 
    } 
}

這裏是我的item_layout.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" > 

    <TextView 
     android:id="@+id/itemName" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:layout_alignParentLeft="true" /> 


</RelativeLayout>

這是一個正被拋出的異常 - 我想

1559-1559/com.example.listviewandroid E/AndroidRuntime﹕ FATAL EXCEPTION: main 
    Process: com.example.listviewandroid, PID: 1559 
    java.lang.NullPointerException 
      at android.widget.AbsListView.obtainView(AbsListView.java:2265) 
      at android.widget.ListView.measureHeightOfChildren(ListView.java:1263) 
      at android.widget.ListView.onMeasure(ListView.java:1175) 
      at android.view.View.measure(View.java:16458) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
      at android.view.View.measure(View.java:16458) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) 
      at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1052) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:590) 
      at android.view.View.measure(View.java:16458) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
      at android.view.View.measure(View.java:16458) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327) 
      at android.view.View.measure(View.java:16458) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
      at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2289) 
      at android.view.View.measure(View.java:16458) 
      at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1914) 
      at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1111) 
      at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1293) 
      at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:998) 
      at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5582) 
      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749) 
      at android.view.Choreographer.doCallbacks(Choreographer.java:562) 
      at android.view.Choreographer.doFrame(Choreographer.java:532) 
      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735) 
      at android.os.Handler.handleCallback(Handler.java:733) 
      at android.os.Handler.dispatchMessage(Handler.java:95) 
      at android.os.Looper.loop(Looper.java:137) 
      at android.app.ActivityThread.main(ActivityThread.java:4998) 
      at java.lang.reflect.Method.invokeNative(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:515) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593) 
      at dalvik.system.NativeStart.main(Native Method)

充氣item_lauout並突出顯示藍色textview如果listview位置索引是1.我在這裏做錯了什麼。

編輯2：

1810-1810/? E/AndroidRuntime﹕ FATAL EXCEPTION: main 
    Process: com.example.listviewandroid, PID: 1810 
    java.lang.NullPointerException 
      at android.widget.AbsListView.obtainView(AbsListView.java:2265) 
      at android.widget.ListView.measureHeightOfChildren(ListView.java:1263) 
      at android.widget.ListView.onMeasure(ListView.java:1175) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) 
      at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) 
      at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1052) 
      at android.widget.LinearLayout.onMeasure(LinearLayout.java:590) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) 
      at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
      at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291) 
      at android.view.View.measure(View.java:16497) 
      at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1916) 
      at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1113) 
      at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1295) 
      at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000) 
      at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5670) 
      at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761) 
      at android.view.Choreographer.doCallbacks(Choreographer.java:574) 
      at android.view.Choreographer.doFrame(Choreographer.java:544) 
      at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747) 
      at android.os.Handler.handleCallback(Handler.java:733) 
      at android.os.Handler.dispatchMessage(Handler.java:95) 
      at android.os.Looper.loop(Looper.java:136) 
      at android.app.ActivityThread.main(ActivityThread.java:5017) 
      at java.lang.reflect.Method.invokeNative(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:515) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) 
      at dalvik.system.NativeStart.main(Native Method)

編輯3：主要活動代碼

package com.example.listviewandroid; 

import android.content.Intent; 
import android.graphics.Color; 
import android.os.Bundle; 
import android.app.Activity; 
import android.view.Menu; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.ArrayAdapter; 
import android.widget.EditText; 
import android.widget.ListView; 
import android.widget.Spinner; 
import android.widget.TextView; 
import android.widget.Toast; 

import android.text.format.Time; 
import java.util.Date; 

public class MainActivity extends Activity { 
    ListView listView ; 
    static final String STE = ""; 
    static final String STM = ""; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 
     if (savedInstanceState !=null) 
     { 
      restoreState(savedInstanceState); 
     } 
     listView = (ListView) findViewById(R.id.listView); 

     TextView textviewmenu= (TextView) findViewById(R.id.textViewMenu); 
     textviewmenu.setBackgroundColor(Color.rgb(89,89,89)); 
     textviewmenu.setTextColor(Color.WHITE); 

     String[] values = getResources().getStringArray(R.array.menuList); 

     ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, 
       android.R.layout.simple_list_item_1, android.R.id.text1, values); 


     // Assign adapter to ListView 
     listView.setAdapter(adapter); 

     listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { 

      @Override 
      public void onItemClick(AdapterView<?> parent, View view, 
            int position, long id) { 

       // ListView Clicked item index 
       int itemPosition  = position; 

       // ListView Clicked item value 
       String itemValue = (String) listView.getItemAtPosition(position); 


       // Show Alert 

       switch(position) 
       { 

        case 1: Intent newActivity = new Intent(MainActivity.this,Activity2.class); 
         startActivity(newActivity); 
         break; 

        case 2: Intent newActivity1 = new Intent(MainActivity.this,Activity3.class); 
         startActivity(newActivity1); 
         break; 
        case 3: Intent newActivity2 = new Intent(MainActivity.this,Activity4.class); 
         startActivity(newActivity2); 
         break; 
        case 4: Intent newActivity3 = new Intent(MainActivity.this,Activity5.class); 
         startActivity(newActivity3); 
         break; 
        case 5: Intent newActivity4 = new Intent(MainActivity.this,Activity6.class); 
         startActivity(newActivity4); 
         break; 

       } 
       Toast.makeText(getApplicationContext(), 
         "Position :"+itemPosition+" ListItem : " +itemValue , Toast.LENGTH_LONG) 
         .show(); 

      } 

     }); 
     Time now = new Time(); 
     now.setToNow(); 
     if (savedInstanceState ==null) 
     { 
     TextView textview2= (TextView)findViewById(R.id.MAtextView2); 
     textview2.setText(now.hour+" : "+now.minute); 
     } 


    } 


    @Override 
    protected void onSaveInstanceState(Bundle outState) { 
     super.onSaveInstanceState(outState); 


     TextView startimetext= (TextView) findViewById(R.id.MAtextView2); 
     outState.putString(STE,startimetext.getText().toString()); 



     TextView endtimetext= (TextView) findViewById(R.id.MAtextView3); 
     outState.putString(STM,startimetext.getText().toString()); 


    } 


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

    public void SetEndTime(View view) { 
     Time now = new Time(); 
     now.setToNow(); 
     TextView textview3= (TextView)findViewById(R.id.MAtextView3); 
     textview3.setText(now.hour+" : "+now.minute); 

    } 

    public void NextActivity(View view) { 
     Intent myIntent = new Intent(MainActivity.this,Activity2.class); 
     MainActivity.this.startActivity(myIntent); 
     this.overridePendingTransition(android.R.anim.slide_in_left,android.R.anim.slide_out_right); 

    } 

    private void restoreState(Bundle savedInstanceState) { 
     TextView startimetext= (TextView) findViewById(R.id.MAtextView2); 

     TextView endtimetext= (TextView) findViewById(R.id.MAtextView3); 


     startimetext.setText(savedInstanceState.getString(STE)); 
     endtimetext.setText(savedInstanceState.getString(STM)); 



    } 
}

來源

2014-02-26 raghu_3

我做了我的答案的變化。它似乎現在工作.. :) ..如果它爲你，請接受我的答案.. :) – mike20132013

我經歷了你的代碼。看起來您每次在新活動開始時都設置相同的列表視圖。首先，它會對你的應用程序承擔太多的負擔，太多的內存損失。我知道你不願意使用片段，但使用片段實際上會使工作更容易。 – mike20132013

@ mike20132013我知道，在移動到碎片之前的下一個兩天，我將使用quickfix。 –

在你getView（）：

@Override 
    public View getView(int position, View convertView, ViewGroup parent) { 

    if (convertView == null) { 

       LayoutInflater inflater = (LayoutInflater) context 
         .getSystemService(Activity.LAYOUT_INFLATER_SERVICE); 
       convertView = inflater.inflate(R.layout.item_layout, null); 
      } 
       TextView tv=(TextView)convertView .findViewById(R.id.itemName); 

       try { 

      if(position ==1){ 

       convertView.setBackgroundColor(Color.GREEN); 
      } 


     } catch (Exception e1) { 
      // TODO Auto-generated catch block 
      e1.printStackTrace(); 
     } 


return convertView; 

}

爲了保持選擇的項目：

第一：在適配器中定義這些東西：

private int selectedIndex; 
    private int selectedColor = Color.parseColor("#1b1b1b"); 


In your adapter class; add this method: 

public void setSelectedIndex(int position) 
    { 
     selectedIndex = position; 
     notifyDataSetChanged(); 
    }

在你的getView（）中添加這些行。

if(selectedIndex!= -1 && position == selectedIndex) 
     { 
      txtTitle.setBackgroundColor(Color.BLACK); 
     } 
     else 
     { 
      txtTitle.setBackgroundColor(selectedColor); 
     }

現在應該工作.. :)

來源

2014-02-26 20:19:59 mike20132013

不起作用。日誌在我的帖子的編輯2中。 –

您還可以在您嘗試使用此適配器的地方提供您的主要活動代碼嗎？因爲適配器對我來說看起來很好。 – mike20132013

，只是添加了主要活動代碼 –

變化if (convertView !=null)到if (convertView ==null)您需要充氣佈局時，你不必爲了重用。

你需要在你的列表視圖中添加一個點擊監聽器來突出顯示一個特定的行/列表項。以下是您可以如何添加點擊偵聽器的方法。更新您的查看以突出顯示它。

lv.setOnItemClickListener(new OnItemClickListener() {

@Override 
    public void onItemClick(AdapterView<?> parent, View view, int position, 
      long id) { 
     Intent intent = new Intent(MainActivity.this, SendMessage.class); 
     String message = "abc"; 
     intent.putExtra(EXTRA_MESSAGE, message); 
     startActivity(intent); 
    } 
});

你設置你的膨脹鑑於變量v和返回convertView。請指定V至convertView或回報v

來源

2014-02-26 18:43:47 Gaurav

不工作，仍然崩潰，同樣的錯誤。 –

我想你水溼使用的ListView匿名類中。你必須使用AdapterView arg0

listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { 

     @Override 
     public void onItemClick(AdapterView<?> arg0, View view, 
       int position, long id) { 
      AnyObject obj=(AnyObject)arg0.getItemAtPosition(position); 

          ........ 
          ......... 
          ......... 

     } 
    });

來源

2014-04-29 15:22:18

Android無法在列表視圖中突出顯示一個項目

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