这是我的CameraActivity.java文件。当我打开相机并拍照时它说'＃34;不幸的是应用程序已经停止工作＆＃34;。捕获图像，当尝试在图像视图上加载图像时它已停止工作。请帮助我解决问题。
package com.example.perade2016;
import java.io.File;
import java.io.FileOutputStream;
import java.util.Date;
import android.Manifest;
import android.app.Activity;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v4.app.ActivityCompat;
import android.util.Log;
import android.widget.ImageView;
public class CameraActivity extends Activity {
private static final String LOG_TAG = "error";
ImageView imageView;
static final int CAM_REQUEST = 1;
Date curentTime;
// Storage Permissions
private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
verifyStoragePermissions(this);
imageView = (ImageView)findViewById(R.id.imageView1);
Intent camera_intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
File file = getFile();
camera_intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
startActivityForResult(camera_intent,CAM_REQUEST);
}
private File getFile()
{
curentTime = new Date();
String root = Environment.getExternalStorageDirectory().toString();
File folder = new File(root + "/Blue_&_Gold_Perade");
if (!folder.mkdirs()) {
Log.e(LOG_TAG, "Directory not created");
}
File image_file = new File(folder,"selfie_cam"+curentTime+".jpg");
return image_file;
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
setAndSaveImageWithOverlay(getBitmapOfSnappedImage());
}
public Bitmap getBitmapOfSnappedImage(){
String root = Environment.getExternalStorageDirectory().toString();
String path = root + "/Blue_&_Gold_Perade"+ "/selfie_cam"+curentTime+".jpg";
File image = new File(path);
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
Bitmap bitmap = BitmapFactory.decodeFile(image.getAbsolutePath(),bmOptions);
return bitmap;
}
public void setAndSaveImageWithOverlay(Bitmap snappedImage){
Bitmap b = Bitmap.createBitmap(snappedImage.getWidth(), snappedImage.getHeight(), Bitmap.Config.ARGB_8888);
//the overlay png file from drawable folder
if (snappedImage.getWidth() > snappedImage.getHeight()) {
Bitmap overlay = BitmapFactory.decodeResource(getResources(), R.drawable.overlay3);
overlay = Bitmap.createScaledBitmap(overlay,snappedImage.getWidth(),snappedImage.getHeight (),false);
//create canvas with a clean bitmap
Canvas canvas = new Canvas(b);
//draw the snappedImage on the canvas
canvas.drawBitmap(snappedImage, 0, 0, new Paint());
//draw the overlay on the canvas
canvas.drawBitmap(overlay, 0, 0, new Paint());
imageView.setImageBitmap(b);
SaveImage(b);}
else {
Bitmap overlay = BitmapFactory.decodeResource(getResources(), R.drawable.overlay2);
overlay = Bitmap.createScaledBitmap(overlay,snappedImage.getWidth(),snappedImage.getHeight (),false);
//create canvas with a clean bitmap
Canvas canvas = new Canvas(b);
//draw the snappedImage on the canvas
canvas.drawBitmap(snappedImage, 0, 0, new Paint());
//draw the overlay on the canvas
canvas.drawBitmap(overlay, 0, 0, new Paint());
imageView.setImageBitmap(b);
SaveImage(b);}
}
private void SaveImage(Bitmap finalBitmap) {
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/Blue_&_Gold_Perade");
myDir.mkdirs();
String fname = "selfie_cam"+curentTime+".jpg";
File file = new File (myDir, fname);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
finalBitmap.compress(Bitmap.CompressFormat.JPEG, 90, out);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Checks if the app has permission to write to device storage
*
* If the app does not has permission then the user will be prompted to grant permissions
*
* @param activity
*/
public static void verifyStoragePermissions(Activity activity) {
// Check if we have write permission
int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (permission != PackageManager.PERMISSION_GRANTED) {
// We don't have permission so prompt the user
ActivityCompat.requestPermissions(
activity,
PERMISSIONS_STORAGE,
REQUEST_EXTERNAL_STORAGE
);
}
}
}
这是logcat中的错误代码。
01-31 22:05:17.939: E/AndroidRuntime(3514): FATAL EXCEPTION: main
01-31 22:05:17.939: E/AndroidRuntime(3514): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=1, result=0, data=null} to activity {com.example.perade2016/com.example.perade2016.CameraActivity}: java.lang.NullPointerException
01-31 22:05:17.939: E/AndroidRuntime(3514): at android.app.ActivityThread.deliverResults(ActivityThread.java:3000)
01-31 22:05:17.939: E/AndroidRuntime(3514): at android.app.ActivityThread.handleSendResult(ActivityThread.java:3043)
01-31 22:05:17.939: E/AndroidRuntime(3514): at android.app.ActivityThread.access$1100(ActivityThread.java:127)
01-31 22:05:17.939: E/AndroidRuntime(3514): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1188)
01-31 22:05:17.939: E/AndroidRuntime(3514): at android.os.Handler.dispatchMessage(Handler.java:99)
01-31 22:05:17.939: E/AndroidRuntime(3514): at android.os.Looper.loop(Looper.java:137)
01-31 22:05:17.939: E/AndroidRuntime(3514): at android.app.ActivityThread.main(ActivityThread.java:4441)
01-31 22:05:17.939: E/AndroidRuntime(3514): at java.lang.reflect.Method.invokeNative(Native Method)
01-31 22:05:17.939: E/AndroidRuntime(3514): at java.lang.reflect.Method.invoke(Method.java:511)
01-31 22:05:17.939: E/AndroidRuntime(3514): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-31 22:05:17.939: E/AndroidRuntime(3514): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-31 22:05:17.939: E/AndroidRuntime(3514): at dalvik.system.NativeStart.main(Native Method)
01-31 22:05:17.939: E/AndroidRuntime(3514): Caused by: java.lang.NullPointerException
01-31 22:05:17.939: E/AndroidRuntime(3514): at com.example.perade2016.CameraActivity.setAndSaveImageWithOverlay(CameraActivity. java:83)
01-31 22:05:17.939: E/AndroidRuntime(3514): at com.example.perade2016.CameraActivity.onActivityResult(CameraActivity.java:67)
01-31 22:05:17.939: E/AndroidRuntime(3514): at android.app.Activity.dispatchActivityResult(Activity.java:4649)
01-31 22:05:17.939: E/AndroidRuntime(3514): at android.app.ActivityThread.deliverResults(ActivityThread.java:2996)
01-31 22:05:17.939: E/AndroidRuntime(3514): ... 11 more
答案 0 :(得分：0)
这里有一些问题。
首先，假设您的过程将在相机应用程序位于前台时出现。这不能保证。您的流程可能会被终止。在这种情况下，curentTime将在您的新活动实例中为null。您需要在保存的实例状态Bundle中保存所需图像的路径，并从新活动实例中的同一Bundle恢复它。
其次，您在两个不同的位置生成该路径，引入了拼写错误或其他错误的可能性。创建路径一次并在两个地方使用相同的值。
第三，你没有处理那条路上没有图片的情况。这可能是因为用户选择不拍照。也可能是用户选择的相机应用程序在其ACTION_IMAGE_CAPTURE支持中有一个错误，它忽略了您的EXTRA_OUTPUT值。你需要优雅地处理这两种情况。
第四，我不建议在文件路径中使用&，因为这是一个保留字符。
第五，您试图拍摄照片而不等待用户授予您运行时权限。将您的拍照逻辑移到onRequestPermissionsResult()，只有在那里持有权限才能拍照。
此代码可能存在其他问题，但其中任何一个都可以解释您的症状。