Question

我想在gridview项目中显示edittext和textview。我覆盖了baseadapter。当我运行它时，它是nullpointer。我检查了数据输出。没关系，活动收到了正确的数据。

MarkViewActivity.java

package com.find.voter;

import java.util.ArrayList;
import java.util.HashMap;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.GridView;
import android.widget.TextView;

public class MarkViewActivity extends Activity{
private GridView gridview;
private ArrayList<String>list;
private Button reset;
private Button confirm;
private int checkNum;
private TextView topTextShow;
private int num1;
private GridAdapter mAdapter;

private boolean haveCookie;
private double []cookie;
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.gridview2);

    gridview=(GridView)findViewById(R.layout.gridview2);
    reset=(Button)findViewById(R.id.reset2);
    confirm=(Button)findViewById(R.id.confirm2);
    topTextShow=(TextView)findViewById(R.id.checknumshow2);
    list=new ArrayList<String>();
    checkNum=0;

    getInput();

    mAdapter=new GridAdapter(list, this, num1,cookie);
//here !!!nullpointer
    gridview.setAdapter(mAdapter);

}

private void getInput(){
    Bundle receiveBundle=this.getIntent().getExtras();
    cookie=receiveBundle.getDoubleArray("marklistcookie");

    num1=receiveBundle.getInt("num1");
    System.out.println(num1+"num1");
    //get num1
    cookie=new double[num1];
    for(int i=0;i<num1;i++){
        list.add((i+1)+"");
    }

}



private void markCheck(){
    int t=num1-checkNum;
    if(t>0){
        new         AlertDialog.Builder(MarkViewActivity.this).setTitle("noteice").setMessage("ddddddd").setPositiveButton("ok", null).show();
    }else{
        Intent send=new Intent();
        Bundle bundle=new Bundle();
        bundle.putDoubleArray("markAnswer", cookie);
        send.putExtra("ans2", bundle);
        MarkViewActivity.this.setResult(2,send);
        MarkViewActivity.this.finish();
    }
}
private void markState(){
    int t=num1-checkNum;
    if(t>0)
        topTextShow.setText("test1");
    else 
        topTextShow.setText("test2");
}
private void dataChanged(){
    mAdapter.notifyDataSetChanged();
    markState();
}

GridAdapter.java

package com.find.voter;
import java.util.ArrayList;
import java.util.HashMap;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.EditText;
import android.widget.TextView;
public class GridAdapter extends BaseAdapter{
private ArrayList<String>list;
private static double isMarked[];
private Context context;
private LayoutInflater infalter=null;
private int num1;
public GridAdapter(ArrayList<String>list,Context context,int num1,double[]xx) {
    this.context=context;
    this.list=list;
    infalter=LayoutInflater.from(context);
    isMarked=xx;
    this.num1=num1;
}
@Override
public int getCount() {
    // TODO Auto-generated method stub
    return list.size();
}
@Override
public Object getItem(int position) {
    // TODO Auto-generated method stub
    return list.get(position);
}
@Override
public long getItemId(int position) {
    // TODO Auto-generated method stub
    return position;
}
public static double [] getIsMarked(){return isMarked;}
public static void setIsMarked(double [] m){
    GridAdapter.isMarked=m;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
    ViewHolder holder=null;
    if(convertView==null){
        holder=new ViewHolder();
        convertView=infalter.inflate(R.layout.itemgrid2, null);
        holder.tv=(TextView)convertView.findViewById(R.id.grid_tv);
        holder.et=(EditText)convertView.findViewById(R.id.grid_edittext);
        convertView.setTag(holder);
    }else{
        holder=(ViewHolder)convertView.getTag();

    }
    holder.tv.setText(list.get(position));
    holder.et.setText(getIsMarked()[position]+"");
    return convertView;
}

public static class ViewHolder {  
    TextView tv;  
    EditText et;
}

}

itemgrid2.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
    android:id="@+id/grid_tv"
    android:layout_height="wrap_content"
    android:layout_gravity="center_vertical"
    android:textSize="50sp"
    android:layout_weight="1" />
    <EditText
    android:id="@+id/grid_edittext"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:ems="10"
    android:inputType="numberDecimal" >

    <requestFocus />
        </EditText>
</LinearLayout>

gridview2.xml

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

<TextView
    android:id="@+id/checknumshow2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentTop="true"
    android:textSize="30sp"
    android:text="" />

<LinearLayout
    android:id="@+id/linear2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
 >
        <Button
    android:id="@+id/reset2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
     style="?android:attr/buttonBarButtonStyle" 
    android:textSize="30sp"
    android:text="@string/reset" />

        <Button
            android:id="@+id/confirm2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
             style="?android:attr/buttonBarButtonStyle" 
                    android:textSize="30sp"
            android:text="@string/confirm" />

</LinearLayout>
<GridView
    android:id="@+id/grid"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
     android:layout_below="@+id/linear2" 
     android:numColumns="auto_fit"  
    android:verticalSpacing="10dp"  
    android:horizontalSpacing="10dp"  
    android:columnWidth="90dp"  
    android:stretchMode="columnWidth"  
    android:gravity="center"  />

logcat

    08-19 10:16:18.412: E/AndroidRuntime(9923): FATAL EXCEPTION: main
08-19 10:16:18.412: E/AndroidRuntime(9923): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.find.voter/com.find.voter.MarkViewActivity}: java.lang.NullPointerException
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.os.Handler.dispatchMessage(Handler.java:99)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.os.Looper.loop(Looper.java:137)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.app.ActivityThread.main(ActivityThread.java:5041)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at java.lang.reflect.Method.invokeNative(Native Method)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at java.lang.reflect.Method.invoke(Method.java:511)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at dalvik.system.NativeStart.main(Native Method)
08-19 10:16:18.412: E/AndroidRuntime(9923): Caused by: java.lang.NullPointerException
08-19 10:16:18.412: E/AndroidRuntime(9923):     at com.find.voter.MarkViewActivity.onCreate(MarkViewActivity.java:44)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.app.Activity.performCreate(Activity.java:5104)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
08-19 10:16:18.412: E/AndroidRuntime(9923):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
08-19 10:16:18.412: E/AndroidRuntime(9923):     ... 11 more

Answer 1

这一行：

gridview=(GridView)findViewById(R.layout.gridview2);

不正确。您想参考R.id.grid

带有Edittext的Android Gridview

1 个答案: