android - 将图片添加到图库时出现 NullPointerException

Question

错误:

FATAL EXCEPTION: main
java.lang.NullPointerException at java.io.File.fixSlashes(File.java:185)
at java.io.File.(File.java:134) at ua.romanpotapskiy.antihawk.prokaton.DeliverActivity.galleryAddPic(DeliverActivity.java:308) at ua.romanpotapskiy.antihawk.prokaton.DeliverActivity.onClick(DeliverActivity.java:246) at android.view.View.performClick(View.java:3511)
at android.view.View$PerformClick.run(View.java:14105)
at android.os.Handler.handleCallback(Handler.java:605)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4424)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
at dalvik.system.NativeStart.main(Native Method)

代码:

private void dispatchTakePictureIntent() {
        Intent takePictureIntent = new Intent("android.media.action.IMAGE_CAPTURE");
        if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
            File photoFile = null;
            try {
                photoFile = createImageFile();
            } catch (IOException ex) {
                Toast.makeText(this, "Error!", Toast.LENGTH_SHORT).show();
            }
            if (photoFile != null) {
                takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
                startActivityForResult(takePictureIntent, 0);
            }
        }
    }

private File createImageFile() throws IOException {
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        imageFileName = "JPEG_" + timeStamp + "_";
        File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES + "/Prokaton/Big");
        File image = File.createTempFile(imageFileName, ".jpg", storageDir);

        mCurrentPhotoPath = image.getAbsolutePath();
        imageName = image.getName();
        ...
        return image;
    }

private void galleryAddPic() {
    Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
    File f = new File(mCurrentPhotoPath);
    Uri contentUri = Uri.fromFile(f);
    mediaScanIntent.setData(contentUri);
    this.sendBroadcast(mediaScanIntent);
}

此行错误:文件 f = 新文件(mCurrentPhotoPath);

Android 4.0.3 上的错误。在另一个版本中工作正常。

Answer 1

根据您发布的代码，我的猜测是您在调用 dispatchTakePictureIntent() 之前遇到了错误，因为正是此方法调用了 createImageFile()将 mCurrentPhotoPath 变量设置为非空值的方法。

一个简单的修复方法是使用非空检查更新 galleryAddPic() 方法，如下所示:

    private void galleryAddPic() {
        Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
        if (mCurrentPhotoPath == null) {
            return;
        }
        File f = new File(mCurrentPhotoPath);
        Uri contentUri = Uri.fromFile(f);
        mediaScanIntent.setData(contentUri);
        this.sendBroadcast(mediaScanIntent);
    }