android - 如何在android中使用imageView解决RunTime错误

Question

我仍然有问题任何身体帮助？请我没有时间。明天是我最后一个研究生项目演示。

(java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.assfar/com.example.assfar.hotel.Hotel_Details}: java.lang.NullPointerException

我在启动活动时遇到了运行时错误

package com.example.assfar.hotel;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.assfar.R;
import com.example.assfar.database.DBHelper;
import com.example.assfar.offers.Customer_Info;


public class Hotel_Details extends Activity{

    private DBHelper dataBase;
    private ImageView imgv;
    private TextView textView;
    private TextView textView2;
    private TextView textView3;
    private Cursor cursor;
    private String price;
    private String hotelDesc;
    private int idValue;
    private byte [] imgByte;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.hotel_details);

        textView = (TextView)findViewById(R.id.hotel_name);
        textView2 = (TextView)findViewById(R.id.hotel_desc);
        textView3 = (TextView)findViewById(R.id.hotel_price);

        imgv = (ImageView)findViewById(R.id.hotel_image);
        imgv.setImageDrawable(null);


       Intent i= getIntent();
        // getting attached intent data
        String item = i.getStringExtra("selected Item");
        int id = i.getIntExtra("hotel_id", 1);


        // displaying selected product name
          textView.setText(item);

       imgByte= null;

       dataBase=  DBHelper.instance();
        SQLiteDatabase db= dataBase.getWritableDatabase();

        cursor= db.rawQuery("select * from hotel_reservation", null);

        if(cursor!=null) {
             if(cursor.moveToFirst());
             {
                 do
                {

                 price = cursor.getString(cursor.getColumnIndex("price"));
                 idValue= cursor.getInt(cursor.getColumnIndex("ReservationID"));
                 hotelDesc= cursor.getString(cursor.getColumnIndex("hotel_Description"));                                                
                 imgByte= cursor.getBlob(cursor.getColumnIndex("hotel_photo"));
                 Bitmap bmp = BitmapFactory.decodeByteArray(imgByte,0,imgByte.length);

                     if(idValue==id){

                       textView2.setText("\n"+hotelDesc);
                      imgv.setImageBitmap(bmp);
                       }

                 } while(cursor.moveToNext());
             }
        }


        Button butt_reserve= (Button)findViewById(R.id.reserve);
        butt_reserve.setOnClickListener(new OnClickListener(){

            @Override
            public void onClick(View v) {
                Intent i=new Intent(Hotel_Details.this,Customer_Info.class);
                startActivity(i);                       
        }

        });

       }
}

日志猫

 05-19 16:53:32.411: E/AndroidRuntime(3661): FATAL EXCEPTION: main
    05-19 16:53:32.411: E/AndroidRuntime(3661): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.assfar/com.example.assfar.hotel.Hotel_Details}: java.lang.NullPointerException
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.os.Handler.dispatchMessage(Handler.java:99)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.os.Looper.loop(Looper.java:137)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.app.ActivityThread.main(ActivityThread.java:5041)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at java.lang.reflect.Method.invokeNative(Native Method)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at java.lang.reflect.Method.invoke(Method.java:511)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at dalvik.system.NativeStart.main(Native Method)
    05-19 16:53:32.411: E/AndroidRuntime(3661): Caused by: java.lang.NullPointerException
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at com.example.assfar.hotel.Hotel_Details.onCreate(Hotel_Details.java:74)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.app.Activity.performCreate(Activity.java:5104)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
    05-19 16:53:32.411: E/AndroidRuntime(3661):     ... 11 more

Answer 1

检查以确保您已在清单中注册您的活动。这是此类错误的最常见原因。