Android 应用程序文件无法附加并作为电子邮件发送

Question

“无法附加文件” 我正在尝试从我的应用程序中附加图像并通过电子邮件将其作为附件发送。但是，一旦我从图库中选择图像，应用程序就会崩溃。它曾经在我第一次执行该应用程序时工作，但现在由于某种原因它似乎不起作用。但后来我通过将代码行更新为：

        attachmentFile = cursor.getString(columnIndex);
        Log.d("Attachment Path: "," " + attachmentFile);

从我的 Logcat 中，我找不到导致此问题的语句。

最初，我指的是这个问题并尝试了这个给出的答案。
“java.lang.NullPointerException: println needs a message”。

“我的 DespatchActivity”

package com.example.despatch4.resiscafftest;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.net.Uri;
import android.widget.Button;
import android.provider.MediaStore;
import android.database.Cursor;
import android.util.Log;
import android.widget.EditText;

import android.widget.CheckBox;
import android.widget.Toast;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class DespatchActivity extends AppCompatActivity {
private Activity activity;

Button Attachment;
String attachmentFile;
Uri URI = null;
int columnIndex;
private static final int PICK_FROM_GALLERY = 101;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_despatch);
    this.setTitle("Residential Scaffold - Despatch");


    final EditText your_name = (EditText) findViewById(R.id.your_name);
    final EditText company_name = (EditText) findViewById(R.id.company_name);
    final EditText your_phone = (EditText) findViewById(R.id.your_ph);
    final EditText your_jobno = (EditText) findViewById(R.id.your_jobno);
    final EditText your_e_d =   (EditText) findViewById(R.id.your_e_d);
    final EditText job_details = (EditText) findViewById(R.id.job_details);
    final EditText your_date = (EditText) findViewById(R.id.your_date);

    Button email = (Button) findViewById(R.id.post_desp_message);
    Attachment = (Button) findViewById(R.id.bt_attach);

    email.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            String name = your_name.getText().toString();
            String companyname = company_name.getText().toString();
            String phone = your_phone.getText().toString();
            String jobno = your_jobno.getText().toString();
            String ed = your_e_d.getText().toString();
            String jobdetails = job_details.getText().toString();
            String date = your_date.getText().toString();

            Intent sendEmail = new Intent(Intent.ACTION_SEND);



            sendEmail.setType("plain/text");
            sendEmail.putExtra(android.content.Intent.EXTRA_EMAIL, new String[]{"Zamil@residentialscaffold.com.au"});

            sendEmail.putExtra(android.content.Intent.EXTRA_TEXT, "Name: " + name + '\n' + '\n'  + "Company Name: " + companyname + '\n' + '\n'
                    + '\n' + "Contact Number: " + phone + '\n' + '\n'  + "Job Number: " + jobno + '\n' + '\n'  +  "Erect/Dismantle: " + ed + '\n' + '\n'  + "Job Details: "
                    + jobdetails + '\n' + '\n'  + "Date Required: " + date);
                if (URI != null) {
                sendEmail.putExtra(Intent.EXTRA_STREAM, selectedImage);
            }
            startActivity(Intent.createChooser(sendEmail, "Send mail..."));

        }
    });


    //attach images
    Attachment.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            openFolder();
        }
    });

}

protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
Uri selectedImage = null;    
if (requestCode == PICK_FROM_GALLERY && resultCode == RESULT_OK) {
        selectedImage = data.getData();
        String[] filePathColumn = { MediaStore.Images.Media.DATA };
        Cursor cursor = getContentResolver().query(selectedImage,filePathColumn, null, null, null);
        cursor.moveToFirst();
        columnIndex = cursor.getColumnIndex(filePathColumn[0]);
        attachmentFile = cursor.getString(columnIndex);
        //Log.e("Attachment Path:", " " , attachmentFile);
        Log.d("Attachment Path: ","null" attachmentFile);
        URI = Uri.parse("file://" + attachmentFile);
        cursor.close();
    }
}

@Override
public void onResume() {
    super.onResume();
}

@Override
protected void onStart() {
    super.onStart();

}

@Override
protected void onStop() {
    super.onStop();

}

private boolean isValidEmail(String email) {
    String EMAIL_PATTERN = "^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"
            + "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$";

    Pattern pattern = Pattern.compile(EMAIL_PATTERN);
    Matcher matcher = pattern.matcher(email);
    return matcher.matches();
}

public void openFolder()
{
    Intent intent = new Intent();
    intent.setType("image/*");
    intent.setAction(Intent.ACTION_GET_CONTENT);
    intent.putExtra("return-data", true);
    startActivityForResult(Intent.createChooser(intent, "Complete action using"), PICK_FROM_GALLERY);
}

}

当我尝试附加文件时，我的 Logcat 中就会发生这种情况：

 01-23 10:23:48.123 4334-4334/com.example.despatch4.resiscafftest 
 D/Attachment Path:: nullnull

电子邮件客户端已成功启动，并显示“无法附加文件”消息。

提前致谢。

Answer 1

sendEmail.putExtra(Intent.EXTRA_STREAM, URI);

将该行更改为

sendEmail.putExtra(Intent.EXTRA_STREAM, data.getData());

data.getData() 是你在onActivityResult() 中得到的那个。`

不要乱找路径。

改为直接使用 uri。

代码也少得多;-)。