列表視圖集適配器沒有在Android Studio中工作

-2

我，馬新的Android編程，我經歷了在使用上有問題listView.setAdapter();列表視圖集適配器沒有在Android Studio中工作

存在不能正常工作，並給予java.lang.NullPointerException 有代碼我的項目名稱是notbad

EditText textheare; 
CheckBox checkBox; 
ImageView imageView; 
public static final int PICK_IMAGE=1; 
Uri selectimage; 
Button finn; 
ListView listView; 
coustem_laout Cous; 

@Override 
protected void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.nodbatplus); 
    subject=(EditText)findViewById(R.id.subject); 
    textheare =(EditText)findViewById(R.id.textheare); 
    checkBox =(CheckBox)findViewById(R.id.checkBox); 
    imageView =(ImageView)findViewById(R.id.notimg); 
    finn=(Button)findViewById(R.id.Fin); 
    listView=(ListView)findViewById(R.id.nameList); 
    finn.setOnClickListener(this); 
    checkBox.setOnCheckedChangeListener(this); 
} 

@Override 
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) 
{ 
    if(checkBox.isChecked()){ 
     opengallary(); 
    } 
    else if (checkBox.isChecked()==false) 
     imageView.setImageBitmap(null); 


} 

public void opengallary(){ 
    Intent gallary=new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.INTERNAL_CONTENT_URI); 
    startActivityForResult(gallary,PICK_IMAGE); 
} 

@Override 
protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
    super.onActivityResult(requestCode, resultCode, data); 
    if (requestCode==PICK_IMAGE && resultCode==RESULT_OK) 
    selectimage=data.getData(); 
    imageView.setImageURI(selectimage); 



} 

@Override 
public void onClick(View v) { 
    String n=textheare.getText().toString(); 
    String s=subject.getText().toString(); 
    int i = imageView.getImageAlpha(); 

    SharedPreferences ss =getSharedPreferences(s,MODE_PRIVATE); 
    SharedPreferences.Editor editor=ss.edit(); 
    editor.putString("notbadtext",n); 

    editor.putInt("imagehere",i); 
    editor.commit(); 

    Cous=new coustem_laout(this,android.R.layout.simple_list_item_1,imageView,subject); 
    listView.setAdapter(Cous); 
    finish(); 
}

且有xml文件按照notbatplus：

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

 
    <RelativeLayout 
 
     android:layout_width="match_parent" 
 
     android:layout_height="250dp"> 
 

 
     <EditText 
 
      android:layout_width="match_parent" 
 
      android:layout_height="match_parent" 
 
      android:inputType="textPersonName" 
 
      android:text="Name" 
 
      android:ems="10" 
 
      android:id="@+id/textheare" 
 
      android:layout_alignParentBottom="true" 
 
      android:layout_alignParentStart="true" 
 
      android:layout_below="@+id/subject" /> 
 

 
     <EditText 
 
      android:layout_width="wrap_content" 
 
      android:layout_height="wrap_content" 
 
      android:inputType="textPersonName" 
 
      android:text="Name" 
 
      android:ems="10" 
 
      android:layout_marginTop="28dp" 
 
      android:id="@+id/subject" 
 
      android:layout_alignParentTop="true" 
 
      android:layout_alignParentStart="true" /> 
 
    </RelativeLayout> 
 

 
    <RelativeLayout 
 
     android:layout_width="match_parent" 
 
     android:layout_height="match_parent"> 
 

 
     <ImageView 
 
      android:layout_width="100dp" 
 
      android:layout_height="100dp" 
 
      android:layout_alignParentTop="true" 
 
      android:layout_alignParentStart="true" 
 
      android:layout_marginStart="26dp" 
 
      android:layout_marginTop="29dp" 
 
      android:id="@+id/notimg" /> 
 

 
     <CheckBox 
 
      android:text="CheckBox" 
 
      android:layout_width="wrap_content" 
 
      android:layout_height="wrap_content" 
 
      android:id="@+id/checkBox" 
 
      android:layout_alignBottom="@+id/imageView" 
 
      android:layout_alignParentEnd="true" 
 
      android:layout_marginEnd="65dp" 
 
      android:layout_marginBottom="28dp" /> 
 

 
     <Button 
 
      android:text="Finish" 
 
      android:layout_width="wrap_content" 
 
      android:layout_height="wrap_content" 
 
      android:layout_alignParentBottom="true" 
 
      android:layout_alignStart="@+id/checkBox" 
 
      android:layout_marginBottom="37dp" 
 
      android:id="@+id/Fin" /> 
 
    </RelativeLayout> 
 
</LinearLayout>

並有mainActivite：

Button bn; 
ListView listView; 
notbad no; 
String subnot; 
int immg; 
SharedPreferences sharedPreferences; 
coustem_laout Coustem_laout; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    bn=(Button)findViewById(R.id.addlist); 
    listView=(ListView)findViewById(R.id.nameList); 

    bn.setOnClickListener(this); 
} 


@Override 
public void onClick(View v) 
{ 
    listView.setVisibility(View.VISIBLE); 
    Intent i =new Intent(MainActivity.this,notbad.class); 

    startActivity(i); 
}

有XML文件，遵循mainActivite：

<?xml version="1.0" encoding="utf-8"?> 
 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 
    xmlns:tools="http://schemas.android.com/tools" 
 
    android:id="@+id/activity_main" 
 
    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.qan.broedc.MainActivity"> 
 

 
    <ListView 
 
     android:layout_width="match_parent" 
 
     android:layout_height="match_parent" 
 
     android:layout_centerVertical="true" 
 
     android:layout_alignParentEnd="true" 
 
     android:id="@+id/nameList" 
 
     android:fastScrollAlwaysVisible="true" 
 
     android:addStatesFromChildren="false" 
 
     android:visibility="gone" /> 
 

 
    <Button 
 
     android:text="add" 
 
     android:layout_width="wrap_content" 
 
     android:layout_height="wrap_content" 
 
     android:layout_alignParentTop="true" 
 
     android:layout_alignParentStart="true" 
 
     android:layout_marginStart="77dp" 
 
     android:layout_marginTop="42dp" 
 
     android:id="@+id/addlist" 
 
     android:onClick="moveto" /> 
 
</RelativeLayout>

類適配器：

public class coustem_laout extends ArrayAdapter { 

public final Context c; 
public int laout; 
public ImageView IMG; 
public EditText Texthear; 
public View view; 
ImageView Addressimage; 
TextView sub; 
LayoutInflater layoutInflater; 


public coustem_laout(Context context, int resource,ImageView img,EditText editText) { 
    super(context, resource); 
    this.c = context; 
    laout=resource; 
    IMG=img; 
    Texthear=editText; 

} 

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

    layoutInflater=(LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE); 

    view = layoutInflater.inflate(laout,parent,false); 
    sub=(TextView)view.findViewById(R.id.name_list); 
    Addressimage=(ImageView)view.findViewById(R.id.imagelist); 
    sub.setText(Texthear.getText().toString()); 
    Addressimage.setImageAlpha(IMG.getImageAlpha()); 
    return view; 

}

}

有錯誤：

11-30 04:10:42.909 1427-1427/com.example.qan.broedc E/AndroidRuntime: FATAL EXCEPTION: main 
                    java.lang.NullPointerException 
                     at com.example.qan.broedc.notbad.onClick(notbad.java:101) 
                     at android.view.View.performClick(View.java:4240) 
                     at android.view.View$PerformClick.run(View.java:17721) 
                     at android.os.Handler.handleCallback(Handler.java:730) 
                     at android.os.Handler.dispatchMessage(Handler.java:92) 
                     at android.os.Looper.loop(Looper.java:137) 
                     at android.app.ActivityThread.main(ActivityThread.java:5103) 
                     at java.lang.reflect.Method.invokeNative(Native Method) 
                     at java.lang.reflect.Method.invoke(Method.java:525) 
                     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737) 
                     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
                     at dalvik.system.NativeStart.main(Native Method)

來源

2016-11-30 وسام الجلاد

你的適配器類在哪裏？ –

你能告訴我們NullPointerException的堆棧跟蹤嗎？同時告訴我們發生了什麼事情。 –

notbad xml佈局中沒有列表視圖，因此列表視圖爲空。很明顯 – Manza

您需要在setAdapter方法來設置的適配器。創建一個新的適配器並將其傳遞給該函數。

來源

2016-11-30 10:33:33

列表視圖集適配器沒有在Android Studio中工作

回答

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