使用android和php将图像上载到服务器（mysql数据库）

在我的代码中，我有两个图像和两个edittext字段要使用php文件发送到数据库。在我的代码中，我能够插入两个图像以及edittext文件，没有任何问题。 现在，我的问题是，当用户输入两个edittext字段并仅选择一个要插入的图像时，它会抛出

NullPointerException

。使用此代码，我必须强制选择两个图像。我如何使这一个图像成为可选的？我的意思是用户可以根据自己的要求选择一个/两个图像。但如果我仅选择一个图像，它正在抛出空指针异常。请帮助我。。！！

MainActivity.java

package com.example.test;

import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.AsyncTask;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Base64;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.HashMap;

public class MainActivity extends Activity implements View.OnClickListener {

    private Button buttonUpload;
    private Button buttonChoose;
    private Button buttonChoose1;

    private EditText edithouse;
    private EditText editbuild;
    private ImageView imageView;
    private ImageView imageView1;

    public static final String KEY_IMAGE = "image";
    public static final String KEY_IMAGE1 = "image1";
    public static final String KEY_TEXT = "house";
    public static final String KEY_TEXT1 = "build";
    public static final String UPLOAD_URL = "http://oursite/PhotoUploadWithText/upload.php";

    private int PICK_IMAGE_REQUEST = 1;
    private int PICK_IMAGE_REQUEST1 = 2;

    private Bitmap bitmap;
    private Bitmap bitmap1;

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

        buttonUpload = (Button) findViewById(R.id.save);
        buttonChoose = (Button) findViewById(R.id.choose);
        buttonChoose1 = (Button) findViewById(R.id.choose1);

        edithouse = (EditText) findViewById(R.id.houseno);
        editbuild = (EditText) findViewById(R.id.buildno);
        imageView = (ImageView) findViewById(R.id.imageViews);
        imageView1 = (ImageView) findViewById(R.id.imageViews1);

        buttonChoose.setOnClickListener(this);
        buttonChoose1.setOnClickListener(this);
        buttonUpload.setOnClickListener(this);
    }

    private void showFileChooser() {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE_REQUEST);
    }
          private void showFileChooser1() {
            Intent intent = new Intent();
            intent.setType("image/*");
            intent.setAction(Intent.ACTION_GET_CONTENT);
            startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE_REQUEST1);
        }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) {
            Uri filePath = data.getData();
            try {
                bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), filePath);
                //bitmap1 = MediaStore.Images.Media.getBitmap(getContentResolver(), filePath);
                imageView.setImageBitmap(bitmap);
               // imageView1.setImageBitmap(bitmap1);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        if (requestCode == PICK_IMAGE_REQUEST1 && resultCode == RESULT_OK && data != null && data.getData() != null) {
            Uri filePath = data.getData();
            try {
                //bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), filePath);
                bitmap1 = MediaStore.Images.Media.getBitmap(getContentResolver(), filePath);
                //imageView.setImageBitmap(bitmap);
                imageView1.setImageBitmap(bitmap1);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    public String getStringImage(Bitmap bmp){
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bmp.compress(Bitmap.CompressFormat.JPEG, 100, baos);
        byte[] imageBytes = baos.toByteArray();
        String encodedImage = Base64.encodeToString(imageBytes, Base64.DEFAULT);
        return encodedImage;
    }

    public String getStringImage1(Bitmap bmp){
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bmp.compress(Bitmap.CompressFormat.JPEG, 100, baos);
        byte[] imageBytes = baos.toByteArray();
        String encodedImage = Base64.encodeToString(imageBytes, Base64.DEFAULT);
        return encodedImage;
    }


    public void uploadImage(){
        final String house = edithouse.getText().toString().trim();
        final String build = editbuild.getText().toString().trim();
        final String image = getStringImage(bitmap);
        final String image1 = getStringImage1(bitmap1);
        class UploadImage extends AsyncTask<Void,Void,String>{
            ProgressDialog loading;
            @Override
            protected void onPreExecute() {
                super.onPreExecute();
                loading = ProgressDialog.show(MainActivity.this,"Please wait...","uploading",false,false);
            }

            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                loading.dismiss();
                Toast.makeText(MainActivity.this,s,Toast.LENGTH_LONG).show();
            }

            @Override
            protected String doInBackground(Void... params) {
                RequestHandler rh = new RequestHandler();
                HashMap<String,String> param = new HashMap<String,String>();
                param.put(KEY_TEXT,house);
                param.put(KEY_TEXT1,build);
                param.put(KEY_IMAGE,image);
                param.put(KEY_IMAGE1,image1);
                String result = rh.sendPostRequest(UPLOAD_URL, param);
                return result;
            }
        }
        UploadImage u = new UploadImage();
        u.execute();
    }


    @Override
    public void onClick(View v) {
        if(v == buttonChoose){
            showFileChooser();
        }
        if(v == buttonUpload){
            uploadImage();
        }
        if(v == buttonChoose1){
            showFileChooser1();
        }
    }
}

---

调用

public void uploadImage（）

检查

也检查

if(image != null)
    param.put(KEY_IMAGE,image);
if(image1 != null)
    param.put(KEY_IMAGE1,image1);

String result = rh.sendPostRequest(UPLOAD_URL, param);

然后在php中检查

按键图像

及

按键图像1

---

exists然后执行任何您想执行的操作，否则php将为未定义的索引抛出一个错误。

您正在选择一个图像，并在uploadimage方法中上载两个图像

只需使用下面的代码，它将为您工作

String image1 = "";
     if(bitmap1!=null)
     image1 = getStringImage1(bitmap1);

---

在

doInBackground（Void…params）

方法中..如果我使用

param.put（KEY\u IMAGE，IMAGE）。它要求将image和image1的修饰符更改为final..但是在
uploadImage（）
方法中，如果我声明为final.inside if语句，它会抛出错误..使image和image1全局变量包我可以帮助，高兴地编码：）在
doInBackground（Void…params）
方法中..如果我使用
param.put（KEY\u image1，image1）。它要求将image1的修饰符更改为final。。但是在
uploadImage（）
方法中，如果我声明为final.inside if语句，它会为image1抛出错误
String image = null;
String image1 = null;
    if(bitmap != null)
        image = getStringImage(bitmap);
    if(bitmap1 != null)
        image1 = getStringImage1(bitmap1);

if(image != null)
    param.put(KEY_IMAGE,image);
if(image1 != null)
    param.put(KEY_IMAGE1,image1);

String result = rh.sendPostRequest(UPLOAD_URL, param);

String image1 = "";
     if(bitmap1!=null)
     image1 = getStringImage1(bitmap1);