使用相机拍摄并裁剪图像捕捉

Question

我正在学习裁剪图像。我遵循这个tutorial。

我完全按照教程，在Android Studio中运行我的代码，当我点击按钮时，它的力量关闭了。请帮我， 这是我从网站上关注的代码。

import android.content.ActivityNotFoundException;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

    final int PIC_CROP = 2;
    final int CAMERA_CAPTURE = 1;
    private Uri picUri;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //retrieve a reference to the UI button
        Button captureBtn = (Button) findViewById(R.id.capture_btn);
        //handle button clicks
        captureBtn.setOnClickListener(this);


    }

    public void onClick(View v) {
        if (v.getId() == R.id.capture_btn) {
            try {
                //use standard intent to capture an image
                Intent captureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                //we will handle the returned data in onActivityResult
                startActivityForResult(captureIntent, CAMERA_CAPTURE);
            } catch (ActivityNotFoundException anfe) {
                //display an error message
                String errorMessage = "Whoops - your device doesn't support capturing images!";
                Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT);
                toast.show();
            }

        }
    }


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

        if (resultCode == RESULT_OK) {
            if (requestCode == CAMERA_CAPTURE) {
                picUri = data.getData();
                performCrop();
            } else if (requestCode == PIC_CROP) {


                //get the returned data
                Bundle extras = data.getExtras();
                //get the cropped bitmap
                Bitmap thePic = extras.getParcelable("data");
                //retrieve a reference to the ImageView
                ImageView picView = (ImageView) findViewById(R.id.picture);
                //display the returned cropped image
                picView.setImageBitmap(thePic);
            }


        }
    }

    private void performCrop() {
        try {

            Intent cropIntent = new Intent("com.android.camera.action.CROP");
            cropIntent.setDataAndType(picUri, "image/*");
            cropIntent.putExtra("crop", "true");
            cropIntent.putExtra("aspectX", 1);
            cropIntent.putExtra("aspectY", 1);
            cropIntent.putExtra("outputX", 256);
            cropIntent.putExtra("outputD", 256);
            cropIntent.putExtra("return-data", true);
            startActivityForResult(cropIntent, PIC_CROP);

        } catch (ActivityNotFoundException anfe) {
            String errorMessage = "Whoops";
            Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT);
            toast.show();
        }
    }
}

这是logcat

05-09 18:26:49.013 2323-2323/com.don.cropping E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.don.cropping, PID: 2323
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=0, data=null} to activity {com.don.cropping/com.don.cropping.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'android.net.Uri android.content.Intent.getData()' on a null object reference
at android.app.ActivityThread.deliverResults(ActivityThread.java:3539)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:3582)
at android.app.ActivityThread.access$1300(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1327)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.net.Uri android.content.Intent.getData()' on a null object reference
at com.don.cropping.MainActivity.onActivityResult(MainActivity.java:56)
at android.app.Activity.dispatchActivityResult(Activity.java:6139)
at android.app.ActivityThread.deliverResults(ActivityThread.java:3535)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:3582) 
at android.app.ActivityThread.access$1300(ActivityThread.java:144) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1327) 
at android.os.Handler.dispatchMessage(Handler.java:102) 
at android.os.Looper.loop(Looper.java:135) 
at android.app.ActivityThread.main(ActivityThread.java:5221) 
at java.lang.reflect.Method.invoke(Native Method) 
at java.lang.reflect.Method.invoke(Method.java:372) 
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)

activity.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.don.cropping.MainActivity">

    <TextView
        android:id="@+id/tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/app_name" />

    <Button
        android:id="@+id/capture_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/capture" />

    <ImageView
        android:id="@+id/picture"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/capture_btn"
        android:layout_margin="5dp"
        android:background="@drawable/pic_border"
        android:contentDescription="@string/picture" />

</LinearLayout>