Android比较2张图片并告诉水果类别是水果(苹果/香蕉)还是不是水果

Question

Android 比较 2 个图像以使用位图代码并告诉水果类别是水果(苹果/香蕉)还是不是水果。

我有问题与 Bitmap 和 BitmapFactory 比较有运行时错误，我有问题的解决方案。

1. activity_main.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"
    tools:context=".MainActivity" >

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_centerHorizontal="true" />

    <Button
        android:id="@+id/buttonIntent"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:text="Gallery" />

    <Button
        android:text="OK to Search"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/buttonIntent"
        android:layout_alignParentRight="true"
        android:layout_alignParentEnd="true"
        android:id="@+id/button" />

</RelativeLayout>

1. activity_main2.xml

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

    <TextView
        android:text="Have fruit as Apple"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true"
        android:id="@+id/textView"
        android:textSize="20sp"
        android:textColor="@android:color/black" />

</RelativeLayout>

1. MainActivity.java

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import java.io.FileNotFoundException;
import java.io.IOException;

public class MainActivity extends Activity {
    public static final int REQUEST_GALLERY = 1;

    // Code to compare picture.
    Bitmap bitmap; // Picture with select file in gallery.
    Bitmap b = BitmapFactory.decodeResource(getResources(), R.drawable.a1); // Picture to compare.
    // Code to compare picture.

    ImageView imageView1;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        imageView1 = (ImageView)findViewById(R.id.imageView);

        Button buttonIntent = (Button)findViewById(R.id.buttonIntent);
        buttonIntent.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
                intent.setType("image/*");
                startActivityForResult(Intent.createChooser(intent
                        , "Select Picture"), REQUEST_GALLERY);
            }
        });

        Button buttonIntent2 = (Button)findViewById(R.id.button);
        buttonIntent2.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                if(bitmap == b) { // Have to error.
                    Intent newActivity = new Intent(MainActivity.this, ActivityForm2.class);
                    startActivity(newActivity);
                }
            }
        });

    }

    public void onActivityResult(int requestCode, int resultCode
            , Intent data) {
        if (requestCode == REQUEST_GALLERY && resultCode == RESULT_OK) {
            Uri uri = data.getData();
            try {
                bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), uri);
                imageView1.setImageBitmap(bitmap);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

1. ActivityForm2.java

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

/**
 * Created by sumate on 10/30/2016 AD.
 */
public class ActivityForm2 extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
    }

}

1. 图片示例

5.1 Image to Bitmap位图；

5.2 图片转Bitmap b = BitmapFactory.decodeResource(getResources(), R.drawable.a1);

1. 运行时错误

11-13 21:08:42.244 26248-26248/com.spv.babaimile.fruitsearchwithpic E/AndroidRuntime: FATAL EXCEPTION: main
                                                                                     Process: com.spv.babaimile.fruitsearchwithpic, PID: 26248
                                                                                     java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.spv.babaimile.fruitsearchwithpic/com.spv.babaimile.fruitsearchwithpic.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
                                                                                         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2548)
                                                                                         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
                                                                                         at android.app.ActivityThread.-wrap12(ActivityThread.java)
                                                                                         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
                                                                                         at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                                         at android.os.Looper.loop(Looper.java:154)
                                                                                         at android.app.ActivityThread.main(ActivityThread.java:6077)
                                                                                         at java.lang.reflect.Method.invoke(Native Method)
                                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
                                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
                                                                                      Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference
                                                                                         at android.content.ContextWrapper.getResources(ContextWrapper.java:86)
                                                                                         at android.view.ContextThemeWrapper.getResourcesInternal(ContextThemeWrapper.java:127)
                                                                                         at android.view.ContextThemeWrapper.getResources(ContextThemeWrapper.java:121)
                                                                                         at com.spv.babaimile.fruitsearchwithpic.MainActivity.<init>(MainActivity.java:22)
                                                                                         at java.lang.Class.newInstance(Native Method)
                                                                                         at android.app.Instrumentation.newActivity(Instrumentation.java:1078)
                                                                                         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2538)
                                                                                         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707) 
                                                                                         at android.app.ActivityThread.-wrap12(ActivityThread.java) 
                                                                                         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460) 
                                                                                         at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                                         at android.os.Looper.loop(Looper.java:154) 
                                                                                         at android.app.ActivityThread.main(ActivityThread.java:6077) 
                                                                                         at java.lang.reflect.Method.invoke(Native Method) 
                                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865) 
                                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755) 

Answer 1

我已经回答将水果与针对 Android 的 OpenCV 颜色 Blob 检测进行比较。

来源:https://github.com/doanga2007/FruitSearch

教程:https://docs.google.com/presentation/d/1s0KvqZm0kmPYRdjQNgKFPan0RjNWBCjkem23UkXh2GE/edit#slide=id.g2e200109_1_0