Android List Veiw

-1

我想要開發Android應用程序，我想以一種很好的方式顯示用戶聯繫人，我使用ListView。但有例外。Android List Veiw

這裏是代碼：

package com.example.list; 

import java.util.ArrayList; 
import java.util.List; 
import android.os.Bundle; 
import android.app.Activity; 
import android.util.SparseBooleanArray; 
import android.view.LayoutInflater; 
import android.view.Menu; 
import android.view.View.OnClickListener; 
import android.view.ViewGroup; 
import android.widget.AdapterView.OnItemClickListener; 
import android.widget.Button; 
import android.content.ContentResolver; 
import android.content.Context; 
import android.database.Cursor; 
import android.provider.ContactsContract; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.ArrayAdapter; 
import android.widget.BaseAdapter; 
import android.widget.CheckBox; 
import android.widget.CompoundButton; 
import android.widget.ListView; 
import android.widget.TextView; 
import android.widget.Toast; 

public class Display extends Activity implements OnItemClickListener{ 

List<String> name1 = new ArrayList<String>(); 
List<String> phno1 = new ArrayList<String>(); 
MyAdapter ma ; 
Button select; 
@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.display); 

    getAllContacts(this.getContentResolver()); 
    ListView lv= (ListView)findViewById(android.R.id.list); 
     ma = new MyAdapter(); 
     lv.setAdapter(ma); 
     lv.setOnItemClickListener(this); 
     lv.setItemsCanFocus(false); 
     lv.setTextFilterEnabled(true); 
     // adding 
     select = (Button) findViewById(R.id.button1); 
    select.setOnClickListener(new OnClickListener() 
    { 

     @Override 
     public void onClick(View v) { 
       StringBuilder checkedcontacts= new StringBuilder(); 
      System.out.println(".............."+ma.mCheckStates.size()); 
      for(int i = 0; i < name1.size(); i++) 

       { 
       if(ma.mCheckStates.get(i)==true) 
       { 
        checkedcontacts.append(name1.get(i).toString()); 
        checkedcontacts.append("\n"); 

       } 
       else 
       { 
        System.out.println("Not Checked......"+name1.get(i).toString()); 
       } 


      } 

      Toast.makeText(Display.this, checkedcontacts,1000).show(); 
     }  
    }); 
} 
@Override 
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) { 
    // TODO Auto-generated method stub 
    ma.toggle(arg2); 
} 

public void getAllContacts(ContentResolver cr) { 

    Cursor phones = cr.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,null,null, null); 
    while (phones.moveToNext()) 
    { 
     String name=phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME)); 
     String phoneNumber = phones.getString(phones.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER)); 
     System.out.println(".................."+phoneNumber); 
     name1.add(name); 
     phno1.add(phoneNumber); 
    } 

    phones.close(); 
} 
class MyAdapter extends BaseAdapter implements CompoundButton.OnCheckedChangeListener 
{ private SparseBooleanArray mCheckStates; 
    LayoutInflater mInflater; 
    TextView tv1,tv; 
    CheckBox cb; 
    MyAdapter() 
    { 
     mCheckStates = new SparseBooleanArray(name1.size()); 
     mInflater = (LayoutInflater)Display.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
    } 
    @Override 
    public int getCount() { 
     // TODO Auto-generated method stub 
     return name1.size(); 
    } 

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

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

     return 0; 
    } 

    @Override 
    public View getView(final int position, View convertView, ViewGroup parent) { 
     // TODO Auto-generated method stub 
     View vi=convertView; 
     if(convertView==null) 
     // vi = mInflater.inflate(R.layout.row, null); 
      vi = mInflater.inflate(R.layout.gg, null); 
     TextView tv= (TextView) vi.findViewById(R.id.textView1); 
     tv1= (TextView) vi.findViewById(R.id.textView2); 
     // cb = (CheckBox) vi.findViewById(R.id.checkBox1); 
     tv.setText("Name :"+ name1.get(position)); 
     tv1.setText("Phone No :"+ phno1.get(position)); 
     cb.setTag(position); 
     cb.setChecked(mCheckStates.get(position, false)); 
     cb.setOnCheckedChangeListener(this); 

     return vi; 
    } 
    public boolean isChecked(int position) { 
      return mCheckStates.get(position, false); 
     } 

     public void setChecked(int position, boolean isChecked) { 
      mCheckStates.put(position, isChecked); 
      System.out.println("hello..........."); 
      notifyDataSetChanged(); 
     } 
     public void toggle(int position) { 
      setChecked(position, !isChecked(position)); 
     } 
    @Override 
    public void onCheckedChanged(CompoundButton buttonView, 
      boolean isChecked) { 
     // TODO Auto-generated method stub 

     mCheckStates.put((Integer) buttonView.getTag(), isChecked);   
    } 
} 
}

這裏是顯示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=".Display" > 
<ListView 
    android:id="@+android:id/list" 
    android:layout_width="match_parent" 
    android:layout_height="wrap_content" 
    android:layout_above="@+id/button1" /> 
<Button 
    android:id="@+id/button1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_alignParentBottom="true" 
    android:layout_centerHorizontal="true" 
    android:text="@string/Select" /> 
<TextView 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="@string/hello_world" />

和行的xml：

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:orientation="vertical" > 
<TextView 
    android:id="@+android:id/textView1" 
    android:layout_width="270dp" 
    android:layout_height="wrap_content" 
    android:text="TextView" /> 

<TextView 
    android:id="@+id/textView2" 
    android:layout_width="243dp" 
    android:layout_height="wrap_content" 
    android:text="TextView" /> 

<CheckBox 
    android:id="@+id/checkBox1" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="@string/CheckBox" />

這裏是logcat的：

04-07 12:35:37.249: E/AndroidRuntime(18080): FATAL EXCEPTION: main 
04-07 12:35:37.249: E/AndroidRuntime(18080): java.lang.NullPointerException 
04-07 12:35:37.249: E/AndroidRuntime(18080): at com.example.list.Display$MyAdapter.getView(Display.java:137) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.widget.AbsListView.obtainView(AbsListView.java:2624) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.widget.ListView.measureHeightOfChildren(ListView.java:1254) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.widget.ListView.onMeasure(ListView.java:1166) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.View.measure(View.java:16829) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.widget.RelativeLayout.measureChild(RelativeLayout.java:698) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:494) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.View.measure(View.java:16829) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.View.measure(View.java:16829) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:302) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.View.measure(View.java:16829) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5245) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2581) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.View.measure(View.java:16829) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2186) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1349) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1532) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1246) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6339) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:791) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.Choreographer.doCallbacks(Choreographer.java:591) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.Choreographer.doFrame(Choreographer.java:561) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:777) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.os.Handler.handleCallback(Handler.java:730) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.os.Handler.dispatchMessage(Handler.java:92) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.os.Looper.loop(Looper.java:137) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at android.app.ActivityThread.main(ActivityThread.java:5450) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at java.lang.reflect.Method.invokeNative(Native Method) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at java.lang.reflect.Method.invoke(Method.java:525) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1187) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003) 
04-07 12:35:37.249: E/AndroidRuntime(18080): at dalvik.system.NativeStart.main(Native Method)

我也不是什麼問題存在。

來源

2014-04-07 user3498588

'cb'爲空。您已將註釋初始化的行註釋掉，但您仍嘗試在其上調用'setTag（position）'......第137行:) –

檢查列表視圖適配器您getView()方法，你都談到的複選框CB起始線

// cb = (CheckBox) vi.findViewById(R.id.checkBox1);

而且row.xml佈局應該是膨脹而不是gg.xml

所以getView()應該有如下：

@Override 
public View getView(final int position, View convertView, ViewGroup parent) { 
    // TODO Auto-generated method stub 
    View vi=convertView; 
    if(convertView==null) 
     vi = mInflater.inflate(R.layout.row, null); 

    TextView tv= (TextView) vi.findViewById(R.id.textView1); 
    tv1= (TextView) vi.findViewById(R.id.textView2); 
    cb = (CheckBox) vi.findViewById(R.id.checkBox1); 
    tv.setText("Name :"+ name1.get(position)); 
    tv1.setText("Phone No :"+ phno1.get(position)); 
    cb.setTag(position); 
    cb.setChecked(mCheckStates.get(position, false)); 
    cb.setOnCheckedChangeListener(this); 

    return vi; 
}

希望它會幫助你..

來源

2014-04-07 10:15:22

謝謝。我是如此的空地它真的有效。 – user3498588

您的歡迎.. ;-) –

試試這個

@Override 

public View getView(final int position, View convertView, ViewGroup parent) { // TODO Auto-generated method stub 

View vi=convertView; 
    if(convertView==null){ 
     vi = mInflater.inflate(R.layout.row, null); 
    }  
    TextView tv= (TextView) vi.findViewById(R.id.textView1); 
    tv1= (TextView) vi.findViewById(R.id.textView2); 
    cb = (CheckBox) vi.findViewById(R.id.checkBox1); 
    tv.setText("Name :"+ name1.get(position)); 
    tv1.setText("Phone No :"+ phno1.get(position)); 
    cb.setTag(position); 
    cb.setOnCheckedChangeListener(this); 
    cb.setChecked(mCheckStates.get(position, false)); 

    return vi;

}

來源

2014-04-07 10:09:19

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